U.S. patent application number 15/907085 was filed with the patent office on 2019-02-07 for methods of 3d printing articles with particles.
This patent application is currently assigned to VoxeI8,Inc.. The applicant listed for this patent is VoxeI8,Inc.. Invention is credited to Travis Alexander Busbee, Avin Dhoble, Clara H. Rhee, Noah Tremblay, Sean Christopher Troiano.
Application Number | 20190039309 15/907085 |
Document ID | / |
Family ID | 63254053 |
Filed Date | 2019-02-07 |
View All Diagrams
United States Patent
Application |
20190039309 |
Kind Code |
A1 |
Busbee; Travis Alexander ;
et al. |
February 7, 2019 |
METHODS OF 3D PRINTING ARTICLES WITH PARTICLES
Abstract
The present invention generally relates to methods of printing
articles using three-dimensional printing and other printing
techniques, and to articles formed from such techniques, including
the printing of articles containing particles. Certain embodiments
are generally directed to composites comprising particles (e.g.,
reinforcing particles), for example, rubber particles. The
particles may be used, for example, to increase slip or abrasion
resistance. The composites may also contain polyurethanes or other
compounds, e.g., to facilitate fabrication, e.g., using
three-dimensional printing and other printing techniques. Other
embodiments are directed to methods of making or using such
articles. For example, in some embodiments, a composite may be
prepared by mixing particles (e.g., reinforcing particles) with at
least a first fluid and a second fluid within a nozzle, such as a
microfluidic printing nozzle, which may be used to direct the
resulting product onto a substrate.
Inventors: |
Busbee; Travis Alexander;
(Somerville, MA) ; Dhoble; Avin; (Waltham, MA)
; Tremblay; Noah; (Pepperell, MA) ; Rhee; Clara
H.; (Somerville, MA) ; Troiano; Sean Christopher;
(Somerville, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VoxeI8,Inc. |
Somerville |
MA |
US |
|
|
Assignee: |
VoxeI8,Inc.
Somerville
MA
|
Family ID: |
63254053 |
Appl. No.: |
15/907085 |
Filed: |
February 27, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62555930 |
Sep 8, 2017 |
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62555874 |
Sep 8, 2017 |
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62555941 |
Sep 8, 2017 |
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62555886 |
Sep 8, 2017 |
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62503261 |
May 8, 2017 |
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62464363 |
Feb 27, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 64/336 20170801;
A43B 13/04 20130101; B29D 35/126 20130101; B41J 2/175 20130101;
B05B 15/55 20180201; B29L 2031/50 20130101; A43B 1/14 20130101;
A43B 23/0215 20130101; B29K 2105/04 20130101; B05B 7/068 20130101;
B05B 7/0408 20130101; B05B 12/1418 20130101; B33Y 10/00 20141201;
B29C 64/112 20170801; A43B 23/0245 20130101; B33Y 70/00 20141201;
B29K 2075/00 20130101; A43B 13/14 20130101; B01F 7/00908 20130101;
B05B 13/0405 20130101; B29D 35/122 20130101; B33Y 80/00 20141201;
B29C 64/165 20170801; B05B 15/25 20180201; A43D 8/00 20130101; B33Y
30/00 20141201; B01F 7/00541 20130101; B01F 7/00216 20130101 |
International
Class: |
B29C 64/336 20060101
B29C064/336; B33Y 10/00 20060101 B33Y010/00; B29C 64/165 20060101
B29C064/165; B33Y 70/00 20060101 B33Y070/00; A43B 13/04 20060101
A43B013/04 |
Claims
1. A method of printing of an article for use in footwear,
comprising: receiving object information associated with the
article; identifying a target material to be printed using the
object information; identifying two or more input materials to
create the target material, at least one of the two or more input
materials comprising particles; identifying a set of printer
settings for printing the target material; generating print
instructions using the set of printer parameters; and printing the
article using the print instructions.
2. The method of claim 1, wherein the target material comprises a
composite.
3. The method of claim 1, wherein the set of printer settings
comprises at least one setting selected from the group consisting
of: a ratio of the two or more input materials to a mixing chamber,
a spin speed of an impeller in the mixing chamber, a sequence of
materials into a mixing chamber, a position of one or more valves
to control material inputs into the mixing chamber, total
cumulative flowrate of all inputs to a mixing chamber, vertical
position of a print head relative to the substrate, speed of
movement of the print head, amount of reverse pumping following a
movement command, temperature of the print head, temperature of a
substrate onto which the article is printed, and the calibration
setting for a material inlet pump.
4. The method of claim 1, wherein the article comprises a gradient
structure.
5. The method of claim 1, wherein printing the article comprises
mixing at least two fluids with particles.
6. The method of claim 1, wherein printing the article comprises
mixing at least three fluids with particles.
7. The method of claim 1, wherein identifying the target material
to be printed using the object information comprises identifying a
gradient structure using the object information.
8. A method of printing of an article, comprising: flowing a first
fluid through a first inlet into a nozzle; flowing a second fluid
through a second inlet into the nozzle; flowing particles into the
nozzle; mixing the first fluid, the second fluid, and the particles
to form a first mixture within the nozzle; and printing the first
mixture onto a substrate from the nozzle.
9. The method of claim 8, comprising printing the first mixture
onto the substrate in at least a first portion.
10. The method of claim 8, wherein the particles comprise a blowing
agent.
11. The method of claim 8, wherein the mixture of the first fluid
and the second fluid cures to form a matrix on the substrate
containing the particles.
12. The method of claim 8, wherein the minimum activation
temperature of the blowing agent is greater than the maximum
temperature in the curing profile of the matrix by at least 10
degrees Celsius.
13. The method of claim 8, wherein the average activation
temperature of the blowing agent is less than the curing
temperature of the matrix by at least 10 degrees Celsius.
14. The method of claim 8, further comprising: flowing the first
fluid through the first inlet into the nozzle; flowing the second
fluid through the second inlet into the nozzle; mixing the first
fluid and the second fluid to form a second mixture within the
nozzle; and printing the second mixture onto a substrate from the
nozzle in at least a second portion.
15-88. (canceled)
89. A method of printing an article, comprising: flowing at least
two inputs into a mixing nozzle to form a first mixture comprising
a blowing agent; flowing at least two inputs into a mixing nozzle
to form a second mixture; depositing a first region comprising the
first mixture to form a first elastomer; depositing a second region
adjacent to the first region, comprising the second mixture to form
a second elastomer; and heating at least the first region of the
article to a temperature greater than or equal to the activation
temperature of the blowing agent; wherein heating at least the
first region of the article causes differential expansion between
the first region and the second region of the article and physical
deformation of the article.
90. The method of claim 89, wherein the second mixture comprises a
blowing agent.
91. The method of claim 89, wherein one of the at least two inputs
to form the first mixture comprises an isocyanate and another of
the at least two inputs to form the first mixture comprises a
polyol system containing the blowing agent.
92. The method of claim 91, further comprising flowing at least a
third input comprising a polyol system into the mixing nozzle to
form the first mixture.
93. The method of claim 89, wherein one of the at least two inputs
to form the second mixture comprises an isocyanate and another of
the at least two inputs to form the second mixture comprises a
polyol system.
94. The method of claim 93, further comprising flowing at least a
third input comprising a polyol system containing a blowing agent
into the mixing nozzle to form the second mixture.
95-102. (canceled)
Description
FIELD
[0001] The present invention generally relates to methods of
printing articles using three-dimensional printing and other
printing techniques, and to articles formed from such techniques,
including the printing of articles containing particles.
BACKGROUND
[0002] The manufacture of composites may involve the expensive and
environmentally hazardous synthesis and incorporation of new
materials. In addition, the properties of composites may be
difficult to control. Improved methods of manufacture of composites
are thus needed.
SUMMARY
[0003] The present invention generally relates to methods of
printing articles using three-dimensional printing and other
printing techniques, and to articles formed from such techniques,
including the printing of articles containing particles. The
subject matter of the present invention involves, in some cases,
interrelated products, alternative solutions to a particular
problem, and/or a plurality of different uses of one or more
systems and/or articles.
[0004] In one aspect, the present invention is generally directed
to a method. In some cases, the method includes a method for
printing an article, e.g., 3D-printing an article, e.g., for use in
footwear. In one set of embodiments, the method includes receiving
object information associated with the article; identifying a
target material to be printed using the object information;
identifying two or more input materials to create the target
material, at least one of the two or more input materials
comprising particles (e.g., reinforcing particles); identifying a
set of printer settings for printing the target material;
generating print instructions using the set of printer parameters;
and printing the article using the print instructions.
[0005] The method, in another set of embodiments, includes flowing
a first fluid through a first inlet into a nozzle; flowing a second
fluid through a second inlet into the nozzle; flowing particles
(e.g., reinforcing particles) into the nozzle; mixing the first
fluid, the second fluid, and the particles (e.g., reinforcing
particles) to form a mixture within the nozzle; and printing the
mixture onto a substrate from the nozzle.
[0006] In one set of embodiments, the method includes flowing a
fluid into a microfluidic printing nozzle, flowing particles (e.g.,
reinforcing particles) into the nozzle, mixing the fluid and the
particles (e.g., reinforcing particles) within the microfluidic
printing nozzle using an impeller to form a mixture, and printing
the mixture onto a substrate.
[0007] In another set of embodiments, the method includes flowing a
first fluid through a first inlet and a second fluid through a
second inlet into a microfluidic printing nozzle, where the first
fluid comprises a foam precursor and the second fluid comprises a
cell-forming agent, homogenously mixing the first fluid and the
second fluid to form a mixture, and printing the mixture onto a
substrate.
[0008] The method, in another set of embodiments, includes flowing
a fluid into a microfluidic printing nozzle, mixing the fluid with
a gas within the microfluidic printing nozzle using an impeller to
form a froth comprising bubbles of the gas dispersed within the
fluid, and printing the froth onto a substrate.
[0009] In another set of embodiments, the method comprises acts of
mixing a first fluid and a second fluid in a mixing chamber to form
a foam precursor, flowing the foam precursor and a cell-forming
agent into a microfluidic printing nozzle, rotating an impeller
within the microfluidic printing nozzle to form a mixture of the
foam precursor and the cell-forming agent, and printing the mixture
onto a substrate.
[0010] The method, in still another set of embodiments comprises
flowing at least two inputs into a mixing nozzle to form a first
mixture comprising a blowing agent. The method may further comprise
flowing at least two inputs into a mixing nozzle to form a second
mixture. A first region comprising the first mixture may be
deposited to form a first elastomer. A second region comprising the
second mixture may be deposited to form a second elastomer. At
least the first region of the article may be heated to a
temperature greater than or equal to the activation temperature of
the blowing agent. In some embodiments, heating at least the first
region of the article causes differential expansion between the
first region and the second region of the article and physical
deformation of the article.
[0011] In another aspect, the present invention is generally
directed to an article. In some embodiments, the article is an
article for use in footwear. In some embodiments, the article
includes a 3D-printed composite comprising a plurality of particles
(e.g., reinforcing particles) having a largest numerical average
dimension of greater than or equal to 10 microns and less than or
equal to 400 microns.
[0012] In another set of embodiments, the article is a 3D-printed
article for use in footwear. In some embodiments, the article
includes a 3D-printed article having a gradient in a property
between a first portion and a second portion, wherein the
3D-printed article is a single integrated material, and wherein the
property is selected from the group consisting of average largest
dimension of particles (e.g., reinforcing particles), weight
percent of particles (e.g., reinforcing particles), volume percent
of particles (e.g., reinforcing particles), compression strength,
slip resistance, abrasion resistance, density, stiffness, heat
deflection temperature, pore concentration, pore size, and
coefficient of thermal expansion.
[0013] In some embodiments, the article comprises a polymeric
structure. The article may comprise particles (e.g., reinforcing
particles) distributed in the polymeric structure to form a
gradient of the weight percent of particles (e.g., reinforcing
particles) in the polymeric structure. In some embodiments, a
textile is adhered to the polymeric structure.
[0014] In some embodiments, the article comprises a polymeric
structure and an unexpanded chemical blowing agent in at least a
portion of the polymeric structure. In some embodiments, a textile
is adhered to at least a portion of the polymeric structure.
[0015] In another aspect, the present invention is generally
directed to a device. In some embodiments, the device is a device
for printing, e.g., 3D-printing. According to one set of
embodiments, the device comprises a first microfluidic printing
nozzle comprising a first mixing chamber and a first impeller
disposed therein, a second microfluidic printing nozzle comprising
a second mixing chamber and a second impeller disposed therein, the
second nozzle further comprising an input in fluid communication
with an outlet of the first nozzle, and a controller configured and
arranged to independently control rotation of the first impeller
and the second impeller.
[0016] In another set of embodiments, the device comprises a
microfluidic printing nozzle comprising a mixing chamber and an
impeller disposed therein, a heat source or a cooling source in
thermal communication with the nozzle, and a controller constructed
and arranged to control rotation of the impeller.
[0017] The device, in yet another set of embodiments, includes a
microfluidic printing nozzle comprising a mixing chamber and an
impeller disposed therein, and a controller constructed and
arranged to laterally move the impeller within the microfluidic
printing nozzle.
[0018] The nozzle may be controlled, for example, using a computer
or other controller, in order to control the deposition of the
product onto the substrate. In some cases, gases or other materials
may be incorporated into the product within the nozzle, e.g., to
form a foam.
[0019] Other advantages and novel features of the present invention
will become apparent from the following detailed description of
various non-limiting embodiments of the invention when considered
in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Non-limiting embodiments of the present invention will be
described by way of example with reference to the accompanying
figures, which are schematic and are not intended to be drawn to
scale. In the figures, each identical or nearly identical component
illustrated is typically represented by a single numeral. For
purposes of clarity, not every component is labeled in every
figure, nor is every component of each embodiment of the invention
shown where illustration is not necessary to allow those of
ordinary skill in the art to understand the invention. In the
figures:
[0021] FIG. 1 illustrates a system comprising a nozzle for printing
materials, in accordance with one embodiment of the invention;
[0022] FIG. 2 illustrates a system comprising a nozzle and a mixing
chamber, in another embodiment of the invention;
[0023] FIG. 3 illustrates a system comprising multiple mixing
chambers, in yet another embodiment of the invention;
[0024] FIG. 4 illustrates a variety of inputs that can be mixed, in
accordance with certain embodiments of the invention;
[0025] FIG. 5 illustrates a system comprising a single input, in
accordance with another embodiment of the invention;
[0026] FIG. 6 illustrates an input comprising a purge system, in
still another embodiment of the invention;
[0027] FIG. 7 illustrates a water-blown polyurethane foam in the
form of a shoe sole, in one embodiment of the invention;
[0028] FIG. 8 illustrates a light microscopy image of a
cross-section of a 3D-printed filament, in accordance with another
embodiment of the invention;
[0029] FIG. 9 illustrates an article with a gradient in properties,
in yet another embodiment of the invention;
[0030] FIG. 10 illustrates a 3D-printed stimuli-responsive
tri-layer polyurethane system in accordance with another embodiment
of the invention;
[0031] FIG. 11 illustrates an example nozzle architecture, in still
another embodiment of the invention;
[0032] FIG. 12 illustrates an example material mixing unit
architecture, in another embodiment of the invention;
[0033] FIGS. 13A-13B illustrate examples of architectures for
various subsystems in certain embodiments of the invention;
[0034] FIGS. 14A-14C illustrate 3D-printed articles according to
certain embodiments of the invention;
[0035] FIG. 15 illustrates an article of footwear according to
certain embodiments of the invention;
[0036] FIG. 16 illustrates a mixing nozzle and associated hardware
printing a composite material in accordance with another embodiment
of the invention;
[0037] FIG. 17 illustrates a non-limiting schematic diagram of a
printed article comprising a blowing agent in the surface layer,
according to certain embodiments of the invention;
[0038] FIG. 18 illustrates a non-limiting schematic diagram of a
printed article comprising a blowing agent dispersed throughout the
printed article with local blowing agent activation, according to
other embodiments of the invention;
[0039] FIG. 19 illustrates a non-limiting schematic diagram of a
printed article comprising a blowing agent dispersed throughout the
printed article with global blowing agent activation and volumetric
expansion of the printed article, in certain embodiments of the
invention;
[0040] FIG. 20 is a schematic depiction of a print head and a
substrate, according to certain embodiments of the invention;
[0041] FIGS. 21-23 are schematic depictions of a multi-axis
deposition system, according to certain embodiments of the
invention; and
[0042] FIG. 24 is a non-limiting flow diagram of a method for
generating print instructions from object information, in
accordance with some embodiments of the invention.
DETAILED DESCRIPTION
[0043] The present invention generally relates to the printing of
materials using three-dimensional printing and other printing
techniques, and to articles formed from such techniques. In some
embodiments, the articles may be articles for use in footwear.
Certain embodiments are generally directed to composites comprising
particles (e.g., reinforcing particles), for example, rubber
particles. The particles may be used, for example, to increase slip
or abrasion resistance. The composites may also contain
polyurethanes or other compounds, e.g., to facilitate fabrication,
e.g., using three-dimensional printing and other printing
techniques. Other embodiments are directed to methods of making or
using such articles. For example, in some embodiments, a composite
may be prepared by mixing particles (e.g., reinforcing particles)
with at least a first fluid and a second fluid within a nozzle,
such as a microfluidic printing nozzle, which may be used to direct
the resulting product onto a substrate.
[0044] In some embodiments, an article that is printed (e.g.,
3D-printed) may comprise a composite. In some embodiments, a
composite may comprise a matrix and a plurality of particles (e.g.,
reinforcing particles). The matrix may include materials such as
polyurethane or other suitable polymers, which may be used to
facilitate manufacturing of articles. Examples of polyurethanes and
other suitable polymers include those described in greater detail
below. In some embodiments, the composite may comprise a foam,
although this is not a requirement in every embodiment. The
particles (e.g., reinforcing particles), in some cases, may provide
for increased slip resistance, e.g., due to increased friction. In
some cases, the particles may provide increased toughness or
resistance to abrasion, for example, of a surface. In certain
cases, the particles may be used for texture, for example, to
produce a coarser or more bumpy surface texture to an article, to
produce a certain appearance or "sheen" to the surface of an
article, or the like. In some embodiments, the particles (e.g.,
reinforcing particles) may comprise rubber. The rubber may arise
from any suitable source, and may include virgin and/or recycled
rubber. The rubber may be natural rubber and/or synthetically
produced rubber. Examples of rubber include, but are not limited
to, ground tire rubber, recycled tire rubber, or the like. The
rubber forming the particles may comprise a variety of polymers,
including but not limited to, natural rubber (e.g., latex rubber),
styrene butadiene (SBR), polyacrylics, polyvinyl acetate (PVA),
polyvinyl chloride (PVC), polychloroprene (neoprene),
polyurethanes, butyl rubbers, or the like. Combinations of these
and/or other rubbers may also be used in some cases. It should be
noted that in some cases, the exact composition of polymers in
rubber particles is unknown. As examples, the rubber may arise from
a variety of natural sources (and thus comprise a variety of
different polymers), the rubber may have been recycled from
different sources (e.g., tires, pencil erasers, balloons, footwear,
or the like), etc. For example, in one set of embodiments, recycled
rubber from sources such as discarded tires may be formed into
particles using techniques such as mechanical grinding, cryogenic
grinding, milling, cutting, shredding, screening, etc.
[0045] In addition, in other embodiments, other materials may be
used for reinforcing particles, e.g., in addition to and/or instead
of rubber particles. Non-limiting examples include silica, fumed
silica, silicon carbide, titanium dioxide, fibers, carbon, carbon
fiber, gypsum, glass fiber, calcium carbonates, nanorods,
microrods, carbon fibers, thermoplastics, or the like. In some
embodiments, the particles may comprise silicone particles, wax
particles, or polytetrafluoroethylene particles, or combinations
thereof. In some embodiments, the particles (e.g., reinforcing
particles) may comprise a thermoplastic polyurethane that has a
blowing agent inside that has yet to be expanded, or an expanded
thermoplastic polyurethane. In some embodiments, the particles
(e.g., reinforcing particles) comprise a blowing agent that
decomposes to gas above an activation temperature. In some
embodiments, the particles comprise azodicarbonamide particles,
sodium bicarbonate particles, hydrazine particles,
toluenesulfonylhydrazine particles, or
oxybisbenzenesulfonylhydrazine particles, or combinations thereof.
In some embodiments, reinforcing particles may comprise hollow or
solid spheres. Such spheres may comprise, as non-limiting examples,
glass or polyurethane. For example, the spheres may be hollow
elastomer spheres (e.g., hollow polyurethane spheres), and the
density of a composite including these spheres may be reduced
relative to the density of a substantially similar composite not
including these spheres.
[0046] Particles (e.g., reinforcing particles) may, in some
embodiments, have a largest numerical average dimension of at least
10 microns, at least 20 microns, at least 30 microns, at least 40
microns, at least 50 microns, at least 60 microns, at least 70
microns, at least 80 microns, at least 90 microns, at least 100
microns, at least 150 microns, at least 200 microns, at least 250
microns, at least 300 microns, at least 350 microns, at least 400
microns, at least 500 microns, at least 700 microns, or at least
900 microns. In some embodiments, the particles (e.g., reinforcing
particles) may have a largest numerical average dimension of at
most 1000 microns, at most 900 microns, at most 700 microns, at
most 500 microns, at most 400 microns, at most 350 microns, at most
300 microns, at most 250 microns, at most 200 microns, at most 150
microns, at most 100 microns, at most 90 microns, at most 80
microns, at most 70 microns, at most 60 microns, at most 50
microns, at most 40 microns, at most 30 microns, or at most 20
microns. Combinations of the above-referenced ranges are also
possible (e.g., at least 10 microns and at most 1000 microns, or at
least 50 microns and at most 400 microns, or at least 50 microns
and at most 250 microns). The particles may be spherical and/or
non-spherical. In some cases, the particles may be present in a
range of sizes and/or shapes (e.g., as in the case of crumb rubber
or ground tire rubber).
[0047] In some embodiments, the surfaces of the particles (e.g.,
reinforcing particles) may be functionalized. Functionalization is
given its ordinary meaning in the art and may refer to the process
of changing the surface chemistry of a material (particles, e.g.,
reinforcing particles, e.g., comprising rubber). In some
embodiments, functionalization involves covalently and/or
non-covalently attaching molecules to the material. In some
embodiments, functionalization of the particles (e.g., reinforcing
particles) is carried out prior to mixing the particles (e.g.,
reinforcing particles) with other material(s) (e.g., a first fluid,
a first fluid and a second fluid, etc.). This functionalization of
particles (e.g., reinforcing particles) may be carried out in order
to improve, as non-limiting examples, certain aspects of the
process of mixing the particles (e.g., reinforcing particles) with
other materials (e.g., fluids), or properties of a
three-dimensionally printed composite that results from depositing
(e.g., 3D-printing) the resulting mixture onto a substrate and
allowing it to solidify.
[0048] For example, by functionalizing the particles (e.g.,
reinforcing particles) prior to introducing the particles into a
mixing nozzle, into which one or more other materials (e.g.,
fluids) are also introduced, the process of mixing the particles
(e.g., reinforcing particles) with the one or more materials (e.g.,
fluids) may be improved by reducing the viscosity of the
composition in the mixing nozzle. In this example, the composition
in the mixing nozzle comprises the particles (e.g., reinforcing
particles) and one or more materials (e.g., fluids). As another
non-limiting example, functionalizing the particles (e.g.,
reinforcing particles) prior to introducing the particles into a
mixing nozzle, into which one or more other materials (e.g.,
fluids) are also introduced, may improve the mechanical properties
(e.g., decrease the maximum local stiffness, increase the overall
toughness) of a three-dimensionally printed composite that results
from depositing (e.g., 3D-printing) the resulting mixture onto a
substrate and allowing it to solidify. These mechanical property
improvements may be compared to a substantially similar composite
comprising non-functionalized particles (e.g., reinforcing
particles).
[0049] In some embodiments, functionalization of the particles
(e.g., reinforcing particles) may improve the properties of the
composition in the mixing nozzle and/or of the deposited (e.g.,
3D-printed) solidified composite by means of, as a non-limiting
example, improving the dispersion (e.g., minimizing aggregation) of
the particles (e.g., reinforcing particles) in the matrix (e.g.,
comprising polyurethane) of the composite. This may be useful, for
example, in embodiments in which the particles (e.g., reinforcing
particles) are introduced into a mixing nozzle at a high loading
relative to the total volume of the composition (e.g., greater than
or equal to 50 volume percent of the composition in the mixing
nozzle). As a non-limiting example, the surfaces of the particles
(e.g., reinforcing particles) may be functionalized with a silane.
Non-limiting examples of silanes include
(3-aminopropyl)triethoxysilane, 3-glycidyloxy
propyltriethoxysilane, 3-glycidyloxy propyltrimethoxysilane,
polyether-functional trimethoxysilane, and vinylsilane. Other
non-limiting examples of chemical groups with which to
functionalize the surfaces of the particles (e.g., reinforcing
particles) include alkyl groups, hydroxyl groups, isocyanate
groups, amine groups, amide groups, aromatic groups, glycidyl
groups, epoxide groups, vinyl groups, acrylate groups, and
methacrylate groups. The surfaces of the particles (e.g.,
reinforcing particles) may be functionalized, as another
non-limiting example, to facilitate bonding (e.g., covalently
bonding) of the particles to the matrix material, e.g., chemically.
This may result, for example, in higher strength and/or abrasion
resistance than in a substantially similar composite wherein the
particles (e.g., reinforcing particles) are not bound. In some
cases, at least 50%, at least 75%, or at least 90% of the surfaces
of the particles may be functionalized, e.g., with silanes and/or
other functional moieties as discussed herein.
[0050] In some embodiments, the incorporation of particles (e.g.,
reinforcing particles) into a composite may result in a change
(e.g., an improvement) in the performance of the composite with
respect to one or more properties (e.g., abrasion resistance, slip
resistance, or the like). As a non-limiting example, a composite
having particles (e.g., reinforcing particles) may have greater
abrasion resistance and/or greater slip resistance than a
substantially similar composite lacking such particles. As another
non-limiting example, a composite may have a lower overall density
than a substantially similar composite lacking particles (e.g.,
reinforcing particles).
[0051] In some embodiments, the incorporation of a certain type of
particles (e.g., reinforcing particles) into the matrix of the
composite may result in a change (e.g., an improvement) in the
performance of the composite with respect to one or more properties
(e.g., physical properties, environmental sustainability, cost, or
the like). In some cases, the use of a filler (e.g., ground tire
rubber) may be beneficial in the object of environmental
sustainability. As a non-limiting example, less waste may be
produced in producing a composite comprising recycled materials,
such as ground tire rubber particles.
[0052] In addition, certain aspects of the invention are generally
directed to methods for printing an article, for example, an
article comprising a composite (e.g., a composite comprising
particles, e.g., reinforcing particles).
[0053] In some embodiments, printing an article (e.g., comprising a
composite) may include flowing particles (e.g., reinforcing
particles, e.g., comprising recycled tire rubber) into a nozzle
(see, e.g., FIG. 16). The nozzle may be a microfluidic printing
nozzle. In some cases, the particles (e.g., reinforcing particles)
flowing into the nozzle are contained within a fluid entering the
nozzle. If more than one fluid enters the nozzle, the reinforcing
particles may be in any one or more of the fluids. The particles
(e.g., reinforcing particles) may also enter into a nozzle in some
cases through an inlet separate from fluids entering the nozzle,
e.g., the particles may enter the nozzle in a dry state in some
cases. The particles may be moved through the inlet into the nozzle
by, for example, a pumping subsystem (e.g., an auger system).
According to some embodiments, printing an article may include
mixing the particles (e.g., reinforcing particles) in the nozzle
with a fluid or a plurality of fluids within the nozzle, to form a
mixture. In some embodiments, the mixture comprises a froth.
Examples of nozzles that can be used include those discussed in
more detail below. See also U.S. Pat. Apl. Ser. No. 62/464,363,
entitled "Techniques and Systems for Three-Dimensional Printing of
Foam and Other Materials," filed Feb. 27, 2017, incorporated herein
by reference in its entirety.
[0054] In some embodiments, the particles (e.g., reinforcing
particles) may be present in an article, e.g., after formation,
such that the article has a weight percent of particles (e.g.,
reinforcing particles) of at least 5 wt %, at least 10 wt %, at
least 15 wt %, at least 20 wt %, at least 25 wt %, at least 30 wt
%, at least 35 wt %, at least 40 wt %, at least 45 wt %, at least
50 wt %, at least 55 wt %, at least 60 wt %, at least 65 wt %, at
least 70 wt %, at least 75 wt %, at least 80 wt %, or at least 85
wt % with respect to the total weight of the article. In some
embodiments, the article has a weight percent of particles (e.g.,
reinforcing particles) of at most 90 wt %, at most 85 wt %, at most
80 wt %, at most 75 wt %, at most 70 wt %, at most 65 wt %, at most
60 wt %, at most 55 wt %, at most 50 wt %, at most 45 wt %, at most
40 wt %, at most 35 wt %, at most 30 wt %, at most 25 wt %, at most
20 wt %, at most 15 wt %, or at most 10 wt % with respect to the
total weight of the article. Combinations of the above-referenced
ranges are also possible (e.g., at least 5 wt % and at most 90 wt
%).
[0055] In some embodiments, the particles (e.g., reinforcing
particles) may be present in an article, e.g., after formation,
such that the article has a volume percent of particles (e.g.,
reinforcing particles) of at least 5 vol %, at least 10 vol %, at
least 15 vol %, at least 20 vol %, at least 25 vol %, at least 30
vol %, at least 35 vol %, at least 40 vol %, at least 45 vol %, at
least 50 vol %, at least 55 vol %, at least 60 vol %, at least 65
vol %, or at least 70 vol % with respect to the total volume of the
article. In some embodiments, the article has a volume percent of
particles (e.g., reinforcing particles) of at most 74 vol %, at
most 70 vol %, at most 65 vol %, at most 60 vol %, at most 55 vol
%, at most 50 vol %, at most 45 vol %, at most 40 vol %, at most 35
vol %, at most 30 vol %, at most 25 vol %, at most 20 vol %, at
most 15 vol %, or at most 10 vol % with respect to with respect to
the total volume of the article. Combinations of the
above-referenced ranges are also possible (e.g., at least 5 vol %
and at most 74 vol %).
[0056] In some embodiments, as discussed in more detail below,
printing a mixture onto a substrate may comprise depositing the
mixture onto a substrate in a layer. In some embodiments, printing
the mixture onto a substrate may comprise depositing the mixture
onto a substrate in a plurality of layers. Printing in a plurality
of layers may involve depositing the mixture onto a substrate in a
first layer (e.g., along a line) and then depositing the mixture
onto a substrate in a second layer (e.g., along the same line, in a
perpendicular line to that of the first layer, etc.). Printing
(e.g., 3D-printing) a plurality of layers may involve depositing a
material in a pre-determined shape with a high degree of precision
and control, using for example a robotic positioning system coupled
with a controller. Those of ordinary skill in the art will be aware
of systems and methods for 3D-printing, which typically involves
the formation of 3-dimensional shapes, e.g., as opposed to
2-dimensional coatings that take the shape of the surface that they
are applied to.
[0057] A variety of 3D-printing techniques are known to those of
ordinary skill in the art, and include, but are not limited to,
additive manufacturing techniques such as direct ink writing (DIW),
stereolithography (SL), fused deposition modeling (FDM), laser
sintering, laminated object manufacturing (LOM), doctor blading,
material spraying, and material jetting. In some embodiments, for
example, 3D-printing comprises depositing a first material in a
first layer via additive manufacturing, removing at least some
material in the first layer via subtractive manufacturing, and
after removing the at least some material in the first layer,
depositing a second material in the first layer via additive
manufacturing. In some embodiments, additive manufacturing
comprises at least one member selected from the group consisting
of: direct ink writing (DIW), stereolithography (SL), fused
deposition modeling (FDM), laser sintering, laminated object
manufacturing (LOM), doctor blading, material spraying, and
material jetting. In some embodiments, subtractive manufacturing
comprises at least one member selected from the group consisting
of: milling, drilling, cutting, etching, grinding, sanding,
planing, and turning.
[0058] In some embodiments, 3D-printing comprises receiving, by a
processing device, a 3D model of an object to be printed;
receiving, by the processing device, information including at least
one material property of a material to be 3D-printed; and
generating, by the processing device, a set of sensor-based printer
control parameters to print the object based, at least in part, on
the sensor input. In some implementations, the processing device is
further adapted to execute instructions for initiating 3D-printing
of the object in the 3D-printer; receiving, during 3D-printing, the
input from the sensor associated with the 3D-printing; and
adjusting at least one printing property based on the sensor input.
In some variations, the sensor is a force probe, a weight sensor,
an optical camera, an imaging device, an in-line imaging device, a
profilometer, a laser measurement device, a 3D scanner, or an
automatic digital multimeter.
[0059] In another non-limiting implementation, 3D-printing includes
obtaining model data representing a 3D model of an object. This
implementation also includes processing the model data to generate
a set of commands to direct a 3D-printer to extrude a material to
form a physical model associated with the object. The set of
commands is executable to cause an extruder (e.g., comprising a
mixing nozzle) of the 3D printer to deposit a first portion of the
material corresponding to a first portion of the physical model, to
clean, to purge, or to clean and purge the extruder after
depositing the first portion of the material, and to deposit a
second portion of the material after cleaning the extruder. The
second portion of the material corresponds to a second portion of
the physical model.
[0060] In certain embodiments, a printed article (e.g., a
3D-printed article comprising a composite) may have a smallest
dimension of greater than 10 mm, greater than 12 mm, greater than
14 mm, greater than 16 mm, greater than 18 mm, or greater than 20
mm.
[0061] In certain embodiments, a printed article (e.g., a
3D-printed article comprising a composite) may have an average
largest dimension of particles (e.g., reinforcing particles) of at
least 10 microns, at least 20 microns, at least 30 microns, at
least 40 microns, at least 50 microns, at least 60 microns, at
least 70 microns, at least 80 microns, at least 90 microns, at
least 100 microns, at least 150 microns, at least 200 microns, at
least 250 microns, at least 300 microns, at least 350 microns, at
least 400 microns, at least 500 microns, at least 700 microns, or
at least 900 microns. In some embodiments, the printed article may
have an average largest dimension of particles (e.g., reinforcing
particles) of at most 1000 microns, at most 900 microns, at most
700 microns, at most 500 microns, at most 400 microns, at most 350
microns, at most 300 microns, at most 250 microns, at most 200
microns, at most 150 microns, at most 100 microns, at most 90
microns, at most 80 microns, at most 70 microns, at most 60
microns, at most 50 microns, at most 40 microns, at most 30
microns, or at most 20 microns. Combinations of the
above-referenced ranges are also possible (e.g., at least 10
microns and at most 1000 microns, or at least 50 microns and at
most 400 microns, or at least 50 microns and at most 250
microns).
[0062] In certain embodiments, a printed article (e.g., a
3D-printed article comprising a composite) may have a compression
strength of at least 0.1 MPa, at least 0.5 MPa, at least 1 MPa, at
least 5 MPa, at least 10 MPa, at least 20 MPa, at least 40 MPa, at
least 80 MPa, at least 100 MPa, at least 200 MPa, at least 300 MPa,
or at least 400 MPa. In some embodiments, a printed article may
have a compression strength of at most 500 MPa, at most 400 MPa, at
most 300 MPa, at most 200 MPa, at most 100 MPa, at most 80 MPa, at
most 40 MPa, at most 20 MPa, at most 10 MPa, at most 5 MPa, at most
1 MPa, or at most 0.5 MPa. Combinations of the above-referenced
ranges are also possible (e.g., at least 0.1 MPa and at most 500
MPa).
[0063] In some embodiments, an article comprising a composite that
is printed (e.g., 3D-printed) may comprise two or more portions,
wherein one or more properties (e.g., average largest dimension of
particles (e.g., reinforcing particles), average concentration of
particles (e.g., reinforcing particles) e.g. weight percent of
particles (e.g., reinforcing particles), surface roughness,
compression strength, slip resistance, abrasion resistance,
density, stiffness, heat deflection temperature, pore
concentration, pore size, and coefficient of thermal expansion) of
a first portion may differ from one or more properties of a second
portion. In some embodiments, the difference in properties between
the first portion and the second portion may comprise a gradient of
the one or more properties (e.g., the property or properties may
vary relatively smoothly from a first value in the first portion to
a second value in the second portion). In other embodiments, there
may be a sharp change in one or more of the properties at a
boundary of one or more of the first portion and the second
portion. In some embodiments, the article may be adhered to a
textile. In some embodiments, the article may comprise a polymer.
In some embodiments, the article may be a component of a shoe
upper. The article may in some cases be printed directly onto a
textile to make up a component of a shoe upper or article of
apparel. Examples of methods of producing such particles, e.g.,
having differences between a first portion and a second portion,
are discussed in more detail below.
[0064] In some embodiments, a method of printing an article may
comprise flowing at least two inputs into a mixing nozzle to form a
first mixture comprising a blowing agent. In some embodiments, one
of the at least two inputs to form the first mixture comprises an
isocyanate and another of the at least two inputs to form the first
mixture comprises a polyol system containing the blowing agent. In
some embodiments, the method further comprising flowing at least a
third input comprising a polyol system into the mixing nozzle to
form the first mixture. In some embodiments, the method may
comprise depositing a first region comprising the first mixture to
form a first elastomer.
[0065] In some embodiments, the method may comprise flowing at
least two inputs into a mixing nozzle to form a second mixture. In
some embodiments, one of the at least two inputs to form the second
mixture comprises an isocyanate and another of the at least two
inputs to form the second mixture comprises a polyol system. In
some embodiments, the second mixture comprises a blowing agent. In
some embodiments, the method further comprises flowing at least a
third input comprising a polyol system containing a blowing agent
into the mixing nozzle to form the second mixture. In some
embodiments, the method may comprise depositing a second region
adjacent to the first region, comprising the second mixture to form
a second elastomer.
[0066] In some embodiments, the method may comprise heating at
least the first region of the article (e.g., at least the first
region and the second region of the article) to a temperature
greater than or equal to the activation temperature of the blowing
agent. In some embodiments, heating at least the first region of
the article causes differential expansion between the first region
and the second region of the article and physical deformation of
the article.
[0067] In some embodiments, as a non-limiting example, input Part A
may comprise isocyanate, input Part B' may comprise a polyol
system, and input Part B'' may comprise a polyol system with a
blowing agent. When Part A and Part B' are mixed, an elastomer
results. When Part A and Part B'' are mixed, an elastomer that will
expand when activated results. When Part A is mixed with Part B'
and Part B'', an elastomer that will expand to a lesser extent than
pure Part A with pure Part B'' (e.g., when in the same ratio as
Part A to Part B' and Part B'' combined) results. If a fourth input
were added, then stiffness as well as expansion on activation could
be controlled.
[0068] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least two portions, at least
one of which comprises a composite (e.g., a printed article that
comprises at least a first portion comprising an elastomer and a
second portion comprising a elastomer containing a blowing agent)
may have a ratio of a property (e.g., average largest dimension of
particles (e.g., reinforcing particles), average concentration of
particles (e.g., reinforcing particles), surface roughness,
compression strength, slip resistance, abrasion resistance,
density, stiffness, heat deflection temperature, pore
concentration, pore size, and/or coefficient of thermal expansion)
of the second portion of the printed article to the same property
of the first portion of the printed article of greater than or
equal to 1.05, greater than or equal to 1.1, greater than or equal
to 1.2, greater than or equal to 1.3, greater than or equal to 1.5,
greater than or equal to 2, or greater than or equal to 5. In some
embodiments, a ratio of the property of the second portion of the
printed article to the same property of the first portion of the
printed article may be less than or equal to 10, less than or equal
to 5, less than or equal to 2, less than or equal to 1.5, less than
or equal to 1.3, less than or equal to 1.2, or less than or equal
to 1.1. Combinations of the above-referenced ranges are also
possible (e.g., greater than or equal to 1.05 and less than or
equal to 10).
[0069] In some embodiments, the gradient in a property (e.g.,
volume percent of particles, e.g., reinforcing particles) in the
article may be present from the surface of the article to greater
than or equal to 10 microns, greater than or equal to 20 microns,
greater than or equal to 30 microns greater than or equal to 50
microns, greater than or equal to 100 microns, greater than or
equal to 500 microns, greater than or equal to 1000 microns, or
greater than or equal to 10000 microns below the surface of the
article. In some embodiments, the gradient in the property may be
present throughout the thickness of the article.
[0070] If two portions having different properties are present, the
portions may differ for a variety of reasons, for example,
different particle compositions, different particle shapes,
different particle sizes, different densities of particles, or the
like. Combinations of any of these are also possible. As a
non-limiting example, if two average particle sizes are present,
then each of the average particle sizes may independently be those
described herein. In certain embodiments, as another example, a
printed article (e.g., a 3D-printed article) that comprises at
least two portions comprising particles (e.g., reinforcing
particles) may have a ratio of the average largest dimension of
particles (e.g., reinforcing particles) in a first portion of the
printed article to the average largest dimension of particles
(e.g., reinforcing particles) in a second portion of the printed
article of greater than or equal to 1.05, greater than or equal to
1.1, greater than or equal to 1.2, greater than or equal to 1.3,
greater than or equal to 1.5, greater than or equal to 2, or
greater than or equal to 5. In some embodiments, a ratio of the
average largest dimension of particles (e.g., reinforcing
particles) in the second portion of the printed article to the
average largest dimension of particles (e.g., reinforcing
particles) in the first portion of the printed article may be less
than or equal to 10, less than or equal to 5, less than or equal to
2, less than or equal to 1.5, less than or equal to 1.3, less than
or equal to 1.2, or less than or equal to 1.1. Combinations of the
above-referenced ranges are also possible (e.g., greater than or
equal to 1.05 and less than or equal to 10).
[0071] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least one portion comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite) may have a weight percent of
particles (e.g., reinforcing particles) in the first portion of the
printed article of at least 5 wt %, at least 10 wt %, at least 15
wt %, at least 20 wt %, at least 25 wt %, at least 30 wt %, at
least 35 wt %, at least 40 wt %, at least 45 wt %, at least 50 wt
%, at least 55 wt %, at least 60 wt %, at least 65 wt %, at least
70 wt %, at least 75 wt %, at least 80 wt %, or at least 85 wt %
with respect to the total weight of the article. In some
embodiments, the first portion of the printed article has a weight
percent of particles (e.g., reinforcing particles) of at most 90 wt
%, at most 85 wt %, at most 80 wt %, at most 75 wt %, at most 70 wt
%, at most 65 wt %, at most 60 wt %, at most 55 wt %, at most 50 wt
%, at most 45 wt %, at most 40 wt %, at most 35 wt %, at most 30 wt
%, at most 25 wt %, at most 20 wt %, at most 15 wt %, or at most 10
wt % with respect to the total weight of the article. Combinations
of the above-referenced ranges are also possible (e.g., at least 5
wt % and at most 90 wt %).
[0072] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least two portions comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite and a second portion
comprising a composite) may have a weight percent of particles
(e.g., reinforcing particles) in the first portion of the printed
article of at least 5 wt %, at least 10 wt %, at least 15 wt %, at
least 20 wt %, at least 25 wt %, at least 30 wt %, at least 35 wt
%, at least 40 wt %, at least 45 wt %, at least 50 wt %, at least
55 wt %, at least 60 wt %, at least 65 wt %, at least 70 wt %, at
least 75 wt %, at least 80 wt %, or at least 85 wt % with respect
to the total weight of the article. In some embodiments, the second
portion of the printed article has a weight percent of particles
(e.g., reinforcing particles) of at most 90 wt %, at most 85 wt %,
at most 80 wt %, at most 75 wt %, at most 70 wt %, at most 65 wt %,
at most 60 wt %, at most 55 wt %, at most 50 wt %, at most 45 wt %,
at most 40 wt %, at most 35 wt %, at most 30 wt %, at most 25 wt %,
at most 20 wt %, at most 15 wt %, or at most 10 wt % with respect
to the total weight of the article. Combinations of the
above-referenced ranges are also possible (e.g., at least 5 wt %
and at most 90 wt %).
[0073] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least two portions comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite and a second portion
comprising a composite) may have a ratio of the weight percent of
particles (e.g., reinforcing particles) in the second portion of
the printed article to the weight percent of particles (e.g.,
reinforcing particles) in the first portion of the printed article
of greater than or equal to 1.05, greater than or equal to 1.1,
greater than or equal to 1.2, greater than or equal to 1.3, greater
than or equal to 1.5, greater than or equal to 2, or greater than
or equal to 5. In some embodiments, a ratio of the weight percent
of particles (e.g., reinforcing particles) in the second portion of
the printed article to the weight percent of particles (e.g.,
reinforcing particles) in the first portion of the printed article
may be less than or equal to 10, less than or equal to 5, less than
or equal to 2, less than or equal to 1.5, less than or equal to
1.3, less than or equal to 1.2, or less than or equal to 1.1.
Combinations of the above-referenced ranges are also possible
(e.g., greater than or equal to 1.05 and less than or equal to
10).
[0074] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least one portion comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite) may have a compression
strength in the first portion of the printed article of at least
0.1 MPa, at least 0.5 MPa, at least 1 MPa, at least 5 MPa, at least
10 MPa, at least 20 MPa, at least 40 MPa, at least 80 MPa, at least
100 MPa, at least 200 MPa, at least 300 MPa, or at least 400 MPa.
In some embodiments, the first portion of the printed article may
have a compression strength of at most 500 MPa, at most 400 MPa, at
most 300 MPa, at most 200 MPa, at most 100 MPa, at most 80 MPa, at
most 40 MPa, at most 20 MPa, at most 10 MPa, at most 5 MPa, at most
1 MPa, or at most 0.5 MPa. Combinations of the above-referenced
ranges are also possible (e.g., at least 0.1 MPa and at most 500
MPa).
[0075] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least two portions comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite and a second portion
comprising a composite) may have a compression strength in the
second portion of the printed article of at least 0.1 MPa, at least
0.5 MPa, at least 1 MPa, at least 5 MPa, at least 10 MPa, at least
20 MPa, at least 40 MPa, at least 80 MPa, at least 100 MPa, at
least 200 MPa, at least 300 MPa, or at least 400 MPa. In some
embodiments, the second portion of the printed article may have a
compression strength of at most 500 MPa, at most 400 MPa, at most
300 MPa, at most 200 MPa, at most 100 MPa, at most 80 MPa, at most
40 MPa, at most 20 MPa, at most 10 MPa, at most 5 MPa, at most 1
MPa, or at most 0.5 MPa. Combinations of the above-referenced
ranges are also possible (e.g., at least 0.1 MPa and at most 500
MPa).
[0076] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least two portions comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite and a second portion
comprising a composite) may have a ratio of compression strength in
the second portion of the printed article to compression strength
in the first portion of the printed article of greater than or
equal to 1.05, greater than or equal to 1.1, greater than or equal
to 1.2, greater than or equal to 1.3, greater than or equal to 1.5,
greater than or equal to 2, or greater than or equal to 5. In some
embodiments, a ratio of compression strength in the second portion
of the printed article to compression strength in the first portion
of the printed article may be less than or equal to 10, less than
or equal to 5, less than or equal to 2, less than or equal to 1.5,
less than or equal to 1.3, less than or equal to 1.2, or less than
or equal to 1.1. Combinations of the above-referenced ranges are
also possible (e.g., greater than or equal to 1.05 and less than or
equal to 10).
[0077] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least two portions comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite and a second portion
comprising a composite) may have a ratio of slip resistance in the
second portion of the printed article to slip resistance in the
first portion of the printed article of greater than or equal to
1.05, greater than or equal to 1.1, greater than or equal to 1.2,
greater than or equal to 1.3, greater than or equal to 1.5, greater
than or equal to 2, or greater than or equal to 5. In some
embodiments, a ratio of slip resistance in the second portion of
the printed article to slip resistance in the first portion of the
printed article may be less than or equal to 10, less than or equal
to 5, less than or equal to 2, less than or equal to 1.5, less than
or equal to 1.3, less than or equal to 1.2, or less than or equal
to 1.1. Combinations of the above-referenced ranges are also
possible (e.g., greater than or equal to 1.05 and less than or
equal to 10).
[0078] In certain embodiments, a printed article (e.g., a
3D-printed article) that comprises at least two portions comprising
a composite (e.g., a printed article that comprises at least a
first portion comprising a composite and a second portion
comprising a composite) may have a ratio of abrasion resistance in
the second portion of the printed article to abrasion resistance in
the first portion of the printed article of greater than or equal
to 1.05, greater than or equal to 1.1, greater than or equal to
1.2, greater than or equal to 1.3, greater than or equal to 1.5,
greater than or equal to 2, or greater than or equal to 5. In some
embodiments, a ratio of abrasion resistance in the second portion
of the printed article to abrasion resistance in the first portion
of the printed article may be less than or equal to 10, less than
or equal to 5, less than or equal to 2, less than or equal to 1.5,
less than or equal to 1.3, less than or equal to 1.2, or less than
or equal to 1.1. Combinations of the above-referenced ranges are
also possible (e.g., greater than or equal to 1.05 and less than or
equal to 10).
[0079] In some embodiments, the particles (e.g., reinforcing
particles) may be incorporated in order to modify the finish of the
printed article. The term finish is given its ordinary meaning in
the art and may refer to the appearance experienced by the viewer.
As non-limiting examples, the finish may be characterized as shiny
or matte.
[0080] In some embodiments, the particles (e.g., reinforcing
particles) may comprise a blowing agent, e.g., solid particles that
decompose, above a certain activation temperature, into a gas. In
some embodiments, the activation temperature of the blowing agent
may be greater than the curing temperature (e.g., the maximum
temperature in the curing profile) of the matrix of the printed
article by e.g. at least 2 degrees Celsius, at least 5 degrees
Celsius, at least 10 degrees Celsius, at least 20 degrees Celsius,
at least 30 degrees Celsius, or at least 50 degrees Celsius. In
some embodiments, the activation temperature of the blowing agent
may be less than the curing temperature of the matrix of the
printed article by e.g. at least 2 degrees Celsius, at least 5
degrees Celsius, at least 10 degrees Celsius, at least 20 degrees
Celsius, at least 30 degrees Celsius, or at least 50 degrees
Celsius, or equal to curing temperature of the matrix of the
printed article. The term activation temperature is given its
ordinary meaning in the art and may refer to the temperature at or
above which a blowing agent comprising solid particles decomposes
into a gas. The term curing temperature is given its ordinary
meaning in the art and may refer to the temperature at or above
which the matrix of the printed article (e.g., comprising
polyurethane) solidifies by e.g. crosslinking.
[0081] In some embodiments, the blowing agent may be incorporated
into the printed article by introducing a fluid comprising a
blowing agent concentrate as one of the inputs of a mixing nozzle
(e.g., a microfluidic printing nozzle) system with a plurality of
inputs. In some embodiments, the blowing agent concentrate may be
made to flow into the mixing nozzle at a constant rate, such that
the volume fraction of solid particles comprising blowing agent in
the matrix of the printed article is constant throughout the
printed object. In some embodiments, the blowing agent concentrate
may be made to flow into the mixing nozzle at a varying rate, such
that the volume fraction of solid particles comprising blowing
agent in the matrix of the printed article varies throughout the
printed object.
[0082] In some embodiments, the blowing agent concentrate is made
to flow into the mixing nozzle at a varying rate as dictated by a
computer. In some embodiments, the blowing agent concentrate is
digitally made to flow into the mixing nozzle at a varying rate,
such that a greater volume fraction of blowing agent is
incorporated into at least a first portion of the printed article
where shrinkage of the matrix during curing is predicted and/or
known to cause warping of the printed article, and a smaller volume
fraction of blowing agent is incorporated into at least a second
portion of the printed article where shrinkage of the matrix during
curing is predicted and/or known not to cause warping of the
printed article.
[0083] In some embodiments, in the case where shrinkage of the
matrix during curing is known to cause warping of at least a first
portion of a printed article, measurement of the extent of warping
of at least a first portion of a first printed article, in which
the first printed article is printed and cured without the
activation of a blowing agent, maybe conducted to determine the
locations of warping. These determined locations of warping can be
used to design the incorporation of varying volume fractions of
blowing agent in at least a first portion and a second portion of a
second printed article, in which a greater volume fraction of
blowing agent is incorporated in at least the first portion of the
second printed article to reduce warping (e.g., resulting from
shrinkage during curing of the matrix) by means of volumetrically
expanding at least the first portion of the second printed article
by heating at least the first portion of the second printed article
above the activation temperature of the blowing agent. The
measurement of the extent of warping of the first printed article
at locations throughout the first printed article may in some
embodiments, as a non-limiting example, be accomplished by the
inclusion of markings in the first printed article and then
video-tracking of the change in position of these markings with
curing.
[0084] In some embodiments, the matrix may shrink during curing by
at least about 0.5% by volume, at least about 1% by volume, at
least about 2% by volume, at least about 3% by volume, at least
about 4% by volume, at least about 5% by volume, at least about 10%
by volume, at least about 15% by volume, at least about 20% by
volume, at least about 30% by volume, or at least about 40% by
volume. In some embodiments, the matrix may shrink during curing by
at most about 50% by volume, at most about 40% by volume, at most
about 30% by volume, at most about 20% by volume, at most about 15%
by volume, at most about 10% by volume, at most about 5% by volume,
most about 4% by volume, at most about 3% by volume, or at most
about 2% by volume.
[0085] In some embodiments, heating at least a first portion of a
printed article, comprising the blowing agent, at or above the
activation temperature of the blowing agent causes a volumetric
expansion of the printed article. In some embodiments, the at least
a first portion of the printed article may volumetrically expand
(e.g., upon heating at or above the blowing agent activation
temperature) by at least about 1% by volume, at least about 2% by
volume, at least about 3% by volume, at least about 4% by volume,
at least about 5% by volume, at least about 10% by volume, at least
about 15% by volume, at least about 20% by volume, at least about
30% by volume, or at least about 40% by volume. In some
embodiments, the at least a first portion of the printed article
may volumetrically expand (e.g., upon heating at or above the
blowing agent activation temperature) by at most about 50% by
volume, at most about 40% by volume, at most about 30% by volume,
at most about 20% by volume, at most about 15% by volume, at most
about 10% by volume, at most about 5% by volume, most about 4% by
volume, at most about 3% by volume, or at most about 2% by
volume.
[0086] In some embodiments, the blowing agent incorporated into at
least a first portion of a printed article may be present in a
volume fraction such that the volumetric expansion provided by the
blowing agent is within about 50%, within about 40%, within about
30%, within about 20%, within about 10%, within about 5%, within
about 2%, within about 1%, or within about 0.5% of the volumetric
shrinkage provided by the curing of the matrix.
[0087] In a non-limiting set of embodiments, the printed article
(FIG. 19, initial printed article 1900) may initially comprise
unexpanded blowing agent (FIG. 19, 1910) prior to heating the
printed article, in which unexpanded blowing agent is homogeneously
distributed throughout the matrix (FIG. 19, 1920) of the printed
article. In this non-limiting set of embodiments, heat is applied
throughout the printed article such that the resulting printed
article (FIG. 19, 1901) comprises expanded blowing agent (FIG. 19,
1930), resulting in a volumetrically expanded printed article.
[0088] A non-limiting set of methods of making article 1900 (FIG.
19) may comprise depositing (e.g., by extrusion through a nozzle)
at least a first layer comprising both matrix and blowing agent in
a volume percentage as described herein. A non-limiting set of
methods of making article 1901 (FIG. 19) may comprise at least one
method of the non-limiting set of methods of making article 1900
followed by applying heat to the entirety of the printed article at
or above the activation temperature of the blowing agent and the
curing temperature of the matrix for a duration such that the
matrix solidifies and the blowing agent expands to form article
1901.
[0089] In some embodiments, the volume fraction of solid blowing
agent in the printed article may be at least about 0.01 volume
percent, at least about 0.1 volume percent, at least about 1 volume
percent, at least about 5 volume percent, at least about 10 volume
percent, at least about 20 volume percent, at least about 30 volume
percent, or at least about 40 volume percent. In some embodiments,
the volume fraction of solid blowing agent in the printed article
may be at most about 50 volume percent, at most about 40 volume
percent, at most about 30 volume percent, at most about 20 volume
percent, at most about 10 volume present, at most about 5 volume
percent, at most about 1 volume percent, or at most about 0.1
volume percent.
[0090] In some embodiments, solid particles of blowing agent may be
incorporated into the entire printed article such that the solid
particles are homogeneously dispersed in the matrix at a constant
volume fraction.
[0091] In some embodiments, the surface of the printed article may
be exposed to a temperature at or above both the curing temperature
of the matrix and the activation temperature of the blowing agent
for a brief period of time, such that only the blowing agent at the
surface of the printed article is activated. In some embodiments,
such treatment of the printed article results in a surface with a
matte finish. In some embodiments, the surface of the printed
article may be exposed to a temperature above both the curing
temperature of the matrix and the activation temperature of the
blowing agent by at least about 0 degrees Celsius, at least about 1
degree Celsius, at least about 2 degrees Celsius, at least about 5
degrees Celsius, at least about 10 degrees Celsius, at least about
15 degrees Celsius, at least about 20 degrees Celsius, at least
about 25 degrees Celsius, at least about 30 degrees Celsius, at
least about 40 degrees Celsius, or at least about 50 degrees
Celsius. In some embodiments, the surface of the printed article
may be exposed to a temperature above both the curing temperature
of the matrix and the activation temperature of the blowing agent
by at most about 60 degrees Celsius, at most about 50 degrees
Celsius, at most about 40 degrees Celsius, at most about 30 degrees
Celsius, and most about 25 degrees Celsius, at most about 20
degrees Celsius, at most about 15 degrees Celsius, at most about 10
degrees Celsius, at most about 5 degrees Celsius, at most about 2
degrees Celsius, or at most about 1 degree Celsius.
[0092] In some embodiments, the surface of the printed article may
be exposed to a temperature at or above both the curing temperature
of the matrix and the activation temperature of the blowing agent
for less than or equal to about 300 seconds, less than or equal to
about 240 seconds, less than or equal to about 180 seconds, less
than or equal to about 120 seconds, less than or equal to about 60
seconds, less than or equal to about 30 seconds, less than or equal
to about 20 seconds, less than or equal to about 10 seconds, less
than or equal to about 5 seconds, less than or equal to about 2
seconds, or less than or equal to about 1 second.
[0093] In some embodiments, a concentrated hot air nozzle maybe
used to locally expose the surface of at least a first portion of a
printed article to a temperature at or above both the curing
temperature of the matrix and the activation temperature of the
blowing agent. In some embodiments, the at least a first portion
that was locally exposed with a concentrated hot air nozzle has a
matte finish.
[0094] In some embodiments, the particles (e.g., reinforcing
particles) may comprise solid particles comprising a blowing agent
that may be incorporated into at least a first portion of the
printed article. In some embodiments, the solid particles
comprising a blowing agent may be incorporated into the printed
article in a gradient. In some embodiments, at least a second
portion of the printed article is free of solid particles
comprising a blowing agent. In a non-limiting set of embodiments,
the surface layer of the printed article (FIG. 17, initial printed
article 1700) may initially comprise unexpanded blowing agent (FIG.
17, 1710) prior to heating the printed article, and the remainder
of the printed article that is not the surface layer may be free of
unexpanded blowing agent and comprise the matrix (FIG. 17, 1720).
In this non-limiting set of embodiments, heat is applied to the
surface of the printed article or to the entire printed article
such that the resulting printed article (FIG. 17, 1701) has a
surface layer comprising expanded blowing agent (FIG. 17, 1730),
resulting in a textured surface that may have a matte finish.
[0095] A non-limiting set of methods of making article 1700 (FIG.
17) may comprise depositing (e.g., by extrusion through a nozzle)
at least a first layer comprising matrix and free of blowing agent,
followed by depositing at least a first surface layer comprising
both matrix and blowing agent in a volume percentage as described
herein. A non-limiting set of methods of making article 1701 (FIG.
17) may comprise at least one method of the non-limiting set of
methods of making article 1700 followed by applying heat to the
surface layer or the entirety of the printed article at or above
both the curing temperature of the matrix and the activation
temperature of the blowing agent for a duration such that the
matrix solidifies and the blowing agent expands to form article
1701.
[0096] In some embodiments, local activation of the blowing agent
may be accomplished by local application of heat to at least a
first portion of the printed article in which the blowing agent has
been incorporated (e.g., by flowing through a mixing nozzle). In
some embodiments, a printed article that has been cured may
comprise bubbles (e.g., that have been formed from the activation
of the blowing agent) and may additionally comprise solid particles
comprising a blowing agent that were intentionally left not
activated. In this case, in some embodiments, the entire printed
article was heated at or above the curing temperature of the
matrix, and at least a first portion of the printed article was
heated at or above the activation temperature of the blowing agent.
In some embodiments, at least a second portion of the printed
article was heated at or above the activation temperature of the
blowing agent, in which case, e.g., the solid particles comprising
a blowing agent remaining as solid particles had an activation
temperature above the curing temperature of the matrix.
[0097] In a non-limiting set of embodiments, the printed article
(FIG. 18, initial printed article 1800) may initially comprise
unexpanded blowing agent (FIG. 18, 1810) prior to heating the
printed article, in which unexpanded blowing agent is homogeneously
distributed throughout the matrix (FIG. 18, 1820) of the printed
article. In this non-limiting set of embodiments, heat is applied
locally to at least a first portion of the surface of the printed
article such that the resulting printed article (FIG. 18, 1801) has
at least the first portion of the surface layer comprising expanded
blowing agent (FIG. 18, 1830), resulting in a partially textured
surface that may have a matte finish in the at least one portion of
the surface layer comprising expanded blowing agent.
[0098] A non-limiting set of methods of making article 1800 (FIG.
18) may comprise depositing (e.g., by extrusion through a nozzle)
at least a first layer comprising both matrix and blowing agent in
a volume percentage as described herein, followed by depositing at
least a first surface layer comprising both matrix and blowing
agent in a volume percentage as described herein. A non-limiting
set of methods of making article 1801 (FIG. 18) may comprise at
least one method of the non-limiting set of methods of making
article 1800 followed by applying heat to at least a first portion
of the surface layer at or above the activation temperature of the
blowing agent and applying heat to the entirety of the printed
article at or above the curing temperature of the matrix for a
duration such that the matrix solidifies and the blowing agent
expands in at least the first portion of the surface layer to form
article 1801. Unexpanded blowing agent in article 1801 (FIG. 18)
results from the blowing agent having an activation temperature
above that of the curing temperature of the matrix.
[0099] In some embodiments, a blowing agent concentrate may be one
of the inputs (e.g., a first fluid) to a mixing nozzle system with
a plurality of inputs. In some embodiments, the volume percent of
blowing agent incorporated into a given portion of the printed
article is digitally controlled. In some embodiments, the entire
printed article is heated at or above the activation temperature of
the blowing agent and at or above the curing temperature of the
matrix, and only at least a first portion of the printed article
comprising the blowing agent volumetrically expand and/or achieve a
different surface texture from the at least a second portion of the
printed article that is free of the blowing agent prior to
heating.
[0100] In some embodiments, a hybrid approach may be taken, in
which a plurality of blowing agents, each with a different
activation temperature and/or a different solid particle size, may
be incorporated into the printed article. In some embodiments, a
low-temperature activating blowing agent may be incorporated that
has an activation temperature at or below the curing temperature of
the matrix and therefore that is activated during curing of the
printed article. In some embodiments, a blowing agent with an
activation temperature above the curing temperature of the matrix
may be incorporated into the printed article and may be activated
by the local application of heat during or after curing the printed
article.
[0101] In some embodiments, an article that changes shape (e.g.,
from deposition to its solid cured and/or activated form) may be
printed by controlling the ratios of two or more inputs into a
mixing nozzle to deposit at least two regions each of which
comprises a respective matrix (e.g., an elastomer) adjacent to one
another where at least one of the regions contains a blowing agent
(e.g., chemical blowing agent) that can be activated at high
temperature. The first region may have the same or different
components from the second region. Following deposition of the at
least two regions, the blowing agent may be activated by heating at
least one portion of the article comprising the blowing agent to a
temperature greater than or equal to the activation temperature of
the blowing agent (and, when applicable, the curing temperature of
the matrix), resulting in a differential expansion between the at
least two regions that causes physical deformation of the article.
In some embodiments, the differential expansion is programmed to
cause the article to better conform to a shoe last.
[0102] In some embodiments, the blowing agent concentration is
varied between the at least two regions by controlling the ratio
between two or more input materials to a mixing nozzle, one or more
of which input materials comprises the blowing agent. In some
embodiments, the stiffness of the matrix (e.g., elastomer) in the
first region may differ from the stiffness of the matrix (e.g.,
elastomer) in the second region (e.g., by varying the concentration
of crosslinking agent between the first region and the second
region). In some embodiments, the differential expansion of the two
or more regions is controlled by the stiffness difference between
the two regions with respect to the matrix (e.g., elastomer) that
encapsulates the blowing agent. In some embodiments, the
differential expansion is controlled by both a difference in
stiffness of the matrix and a difference in blowing agent
concentration between the two or more regions. In some embodiments,
the differential expansion is controlled by a difference between
the first region and the second region of the density, blowing
agent concentration, pore concentration, pore size, stiffness, heat
deflection temperature, coefficient of thermal expansion, and/or
filler concentration.
[0103] In certain embodiments, the printed article may have a ratio
of the concentration of blowing agent in the first region prior to
heating, to the concentration of blowing agent in the second region
prior to heating, of greater than or equal to 1.05, greater than or
equal to 1.1, greater than or equal to 1.2, greater than or equal
to 1.3, greater than or equal to 1.5, greater than or equal to 2,
or greater than or equal to 5. In some embodiments, a ratio of the
concentration of blowing agent in the first region prior to
heating, to the concentration of blowing agent in the second region
prior to heating, may be less than or equal to 10, less than or
equal to 5, less than or equal to 2, less than or equal to 1.5,
less than or equal to 1.3, less than or equal to 1.2, or less than
or equal to 1.1. Combinations of the above-referenced ranges are
also possible (e.g., greater than or equal to 1.05 and less than or
equal to 10).
[0104] In certain embodiments, the printed article may have a ratio
of the concentration of crosslinking agent in the first region
prior to heating, to the concentration of crosslinking agent in the
second region prior to heating, of greater than or equal to 1.05,
greater than or equal to 1.1, greater than or equal to 1.2, greater
than or equal to 1.3, greater than or equal to 1.5, greater than or
equal to 2, or greater than or equal to 5. In some embodiments, a
ratio of the concentration of crosslinking agent in the first
region prior to heating, to the concentration of crosslinking agent
in the second region prior to heating, may be less than or equal to
10, less than or equal to 5, less than or equal to 2, less than or
equal to 1.5, less than or equal to 1.3, less than or equal to 1.2,
or less than or equal to 1.1. Combinations of the above-referenced
ranges are also possible (e.g., greater than or equal to 1.05 and
less than or equal to 10). In some embodiments, the activation
temperature of the blowing agent may be greater than or equal to
200 degrees Celsius, greater than or equal to 250 degrees Celsius,
greater than or equal to 300 degrees Celsius, greater than or equal
to 350 degrees Celsius greater than or equal to 400 degrees
Celsius, greater than or equal to 450 degrees Celsius, greater than
or equal to 500 degrees Celsius, greater than or equal to 550
degrees Celsius, greater than or equal to 600 degrees Celsius,
greater than or equal to 650 degrees Celsius, or greater than or
equal to 700 degrees Celsius. In some embodiments, the activation
temperature of the blowing agent may be less than or equal to 750
degrees Celsius, less than or equal to 700 degrees Celsius, less
than or equal to 650 degrees Celsius, less than or equal to 600
degrees Celsius, less than or equal to 550 degrees Celsius, less
than or equal to 500 degrees Celsius, less than or equal to 450
degrees Celsius, less than or equal to 400 degrees Celsius, less
than or equal to 350 degrees Celsius, less than or equal to 300
degrees Celsius, or less than or equal to 250 degrees Celsius.
Combinations of these activation temperatures are also possible
(e.g., greater than or equal to 200 degrees Celsius and less than
or equal to 750 degrees Celsius).
[0105] In some embodiments, the at least one portion of the article
may be heated to a temperature greater than or equal to the
activation temperature of the blowing agent (and, when applicable,
the curing temperature of the matrix) for greater than or equal to
1 minute, greater than or equal to 2 minutes, greater than or equal
to 5 minutes, greater than or equal to 30 minutes, or greater than
or equal to 60 minutes. In some embodiments, the at least one
portion of the article may be heated to a temperature greater than
or equal to the activation temperature of the blowing agent for
less than or equal to 120 minutes, less than or equal to 60
minutes, less than or equal to 30 minutes, less than or equal to 5
minutes, or less than or equal to 2 minutes. Combinations of these
heating durations are also possible (e.g., greater than or equal to
1 minute and less than or equal to 120 minutes).
[0106] In some embodiments, an article may comprise a polymeric
structure. In some embodiments, the polymeric structure may
comprise a polymer. In some embodiments, the polymeric structure
may comprise particles (e.g., reinforcing particles) (e.g.,
comprising a chemical blowing agent). In some embodiments, the
polymeric structure has a gradient in volume percent of particles
(e.g., reinforcing particles). At least one portion of the
polymeric structure in some embodiments may be adhered to a
textile. In some cases, the polymeric structure may contain in at
least one portion a chemical blowing agent that has not been
expanded. In some cases, the polymeric structure may contain in at
least one portion pores from chemical blowing agent that has been
expanded. In some embodiments, the surface roughness of the
polymeric structure may be increased by heating the polymeric
structure at a portion containing chemical blowing agent to a
temperature greater than or equal to the activation temperature of
the blowing agent.
[0107] In some embodiments, one or more materials deposited onto a
substrate (e.g., by a print head such as a nozzle) may comprise
reactive functional groups for a period of time after deposition.
The reactive functional groups may be configured to react with
other articles to which the deposited material is adjacent (e.g.,
articles of footwear, components of articles of footwear), such as
an article onto which the material was deposited, an article added
to the deposited material, an article positioned beside the
deposited material, an article disposed on the same article onto
which the material was deposited, and/or an article that is
positioned partially above or below the deposited material and
partially beside the deposited material. Reaction between the
reactive functional groups in the deposited material and one or
more articles to which it is adjacent may result in bond formation
between the deposited material and the articles(s), and/or may
increase the adhesive strength between the deposited material and
the article(s). Examples of such articles include textiles, molded
parts, layers, further deposited materials with the same or
different chemistry, and the like. In some embodiments, the
deposited material may bond with two or more articles to which it
is adjacent, and may adhere these articles together through bonds
formed by reaction of the reactive functional groups in the
deposited material with the articles. Each article adhered together
may comprise a deposited material (e.g., a 3D-printed article may
be built up by successively depositing layers of materials
comprising reactive functional groups on top of each other), some
of the articles adhered together may comprise a deposited material
(e.g., a deposited material may adhere another deposited material
to which it is adjacent to a textile on which they are both
disposed), or none of the articles adhered together may comprise a
deposited material. In some cases, the articles adhered together
may have different physical or chemical properties (e.g., different
values of toughness, different values of Young's modulus).
[0108] In some embodiments, reactive functional groups that are
configured to react with an article to which a deposited material
is adjacent (e.g., an article of footwear, a component of an
article of footwear) may also be configured to react with other
reactive functional groups in the deposited material. Reaction
between two complementary sets of functional groups within the
deposited material may comprise curing of the material. As the
deposited material cures, the number of reactive functional groups
within the deposited material may be reduced and the deposited
material may become less reactive with any articles to which it is
adjacent. In certain cases, tuning the curing time of the deposited
material by varying one or more parameters (e.g., temperature at
which the deposited material is held after deposition, composition
of the deposited material) may be advantageous because it may allow
for tuning of the reactivity of the deposited material as a
function of time. For example, the curing time may be tuned so that
the deposited material is adhesive upon deposition and upon further
addition of a second article to the deposited material, but is no
longer adhesive during further manufacturing steps and/or when an
article of which the deposited material is a part of is in use.
[0109] A variety of suitable reactive functional groups and
molecules comprising reactive functional groups may be included in
a deposited material. In some embodiments, a deposited material may
comprise reactive functional groups that are alcohol groups and
reactive functional groups that are isocyanate groups, and the
alcohol groups and isocyanate groups may react to form a
polyurethane. In some embodiments, a deposited material may
comprise reactive functional groups that are amine groups and
reactive functional groups that are isocyanate groups, and the
alcohol groups and isocyanate groups may react to form a polyureas.
Non-limiting examples of suitable molecules comprising alcohol
groups include difunctional hydroxyl compounds such as
1,4-butanediol, hydroquinone bis(2-hydroxylethyl) ether, neopentyl
glycol, diethanolamine, and methyldiethanolamine; trifunctional
hydroxyl compounds such as trimethylolpropane, 1,2,6-hexanetriol,
and triethanolamine; tetrafunctional hydroxyl compounds such as
pentaerythritol; and polyols such as polyether polyols, polyester
polyols, polytetrahydrofuran, polycaprolactone polyols,
polycarbonate polyols, and polytetramethylene ether glycol-based
polyols. Non-limiting examples of suitable molecules comprising
amine groups include difunctional amine compounds such as
diethyltoluenediamine and dimethylthiotoluenediamine. Non-limiting
examples of suitable molecules comprising isocyanate groups include
methylenebis(phenyl isocyanate), toluene diisocyanate,
hexamethylene diisocyanate, naphthalene diisocyanate, methylene
bis-cyclohexylisocyanate, and isophorone diisocyanate. Other types
of reactive functional groups, and other types of molecules
comprising reactive functional groups are also possible.
[0110] In some embodiments, a deposited material may be cured
(and/or configured to be cured) at room temperature. In some
embodiments, the deposited material may be cured (and/or configured
to be cured) at a temperature above room temperature. The deposited
material may be configured (and/or configured to be cured) to be
cured at a temperature of greater than or equal to 70.degree. C.,
greater than or equal to 80.degree. C., greater than or equal to
90.degree. C., or greater than or equal to 100.degree. C. The
deposited material may be cured (and/or configured to be cured) at
a temperature of less than or equal to 110.degree. C., less than or
equal to 100.degree. C., less than or equal to 90.degree. C., or
less than or equal to 80.degree. C. Combinations of the
above-referenced ranges are also possible (e.g., greater than or
equal to 70.degree. C. and less than or equal to 110.degree. C.).
Other ranges are also possible.
[0111] A deposited material may be cured (and/or configured to be
fully cured) over any suitable period of time. In some embodiments,
the deposited material is fully cured (and/or configured to be
cured) over a period of time of greater than or equal to two hours,
greater than or equal to four hours, greater than or equal to eight
hours, greater than or equal to 12 hours, greater than or equal to
20 hours, greater than or equal to 24 hours, greater than or equal
to 36 hours, greater than or equal to 48 hours, greater than or
equal to three days, greater than or equal to four days, greater
than or equal to five days, or greater than or equal to six days.
In some embodiments, the deposited material is fully cured (and/or
configured to be fully cured) over a period of time of less than or
equal to one week, less than or equal to six days, less than or
equal to five days, less than or equal to four days, less than or
equal to three days, less than or equal to 48 hours, less than or
equal to 36 hours, less than or equal to 24 hours, less than or
equal to 20 hours, less than or equal to 12 hours, less than or
equal to eight hours, or less than or equal to four hours.
Combinations of the above-referenced ranges are also possible
(e.g., greater than or equal to two hours and less than or equal to
20 hours, or greater than or equal to 24 hours and less than or
equal to one week). Other ranges are also possible. In general,
higher curing temperatures result in faster reactions between
reactive functional groups. This may cause the time over which the
deposited material is fully cured (and/or configured to be fully
cured) to decrease. For example, a material may be fully cured over
a period of time of greater than or equal to a few days and less
than or equal to one week when cured at room temperature but may be
fully cured over a period of time of greater than or equal to two
hours and less than or equal to 20 hours at a temperature of
greater than or equal to 70.degree. C. and less than or equal to
110.degree. C.
[0112] A deposited material may be deposited at any degree of
curing. In some embodiments, the deposited material is at least 25%
uncured upon deposition, at least 30% uncured upon deposition, at
least 40% uncured upon deposition, at least 50% uncured upon
deposition, at least 60% uncured upon deposition, at least 70%
uncured upon deposition, at least 80% uncured upon deposition, or
at least 90% uncured upon deposition. In some embodiments, the
deposited material is at most 95% uncured upon deposition, at most
90% uncured upon deposition, at most 80% uncured upon deposition,
at most 70% uncured upon deposition, at most 60% uncured upon
deposition, at most 50% uncured upon deposition, or at most 40%
uncured upon deposition. Combinations of the above-referenced
ranges are also possible (e.g., at least 30% uncured upon
deposition and at most 95% uncured upon deposition). Other ranges
are also possible.
[0113] In some embodiments, an article (e.g., an article of
footwear, a component of an article of footwear) is positioned
adjacent to a deposited material (e.g., deposited on the deposited
material, deposited adjacent the deposited material, laminated to
the deposited material, etc.) before it has fully cured. The
article may be positioned adjacent to the deposited material before
at least 25% of the deposited material has cured, before at least
30% of the deposited material has cured, before at least 40% of the
deposited material has cured, before at least 50% of the deposited
material has cured, or before at least 60% of the deposited
material has cured. The article may be positioned adjacent to the
deposited material before at most 70% of the deposited material has
cured, before at most 60% of the deposited material has cured,
before at most 50% of the deposited material has cured, before at
most 40% of the deposited material has cured, or before at most 30%
of the deposited material has cured. Combinations of the
above-referenced ranges are also possible (e.g., before at least
25% of the deposited material has cured and before at most 70% of
the deposited material has cured). Other ranges are also
possible.
[0114] In certain embodiments, an article (e.g., an article of
footwear, a component of an article of footwear, an article of
apparel such as a sports bra, a component of an article of apparel
such as a sports bra) as described herein may be produced on a
multi-axis deposition system, and/or a method as described herein
may include at least one step that is performed on a multi-axis
deposition system. In general, and as described further below,
multi-axis deposition systems include a print head and a substrate.
The print head may be any suitable print head configured to deposit
a material onto the substrate. The substrate may be any suitable
substrate onto which a material may be deposited; in some
embodiments, one or more articles (e.g., a component of an article
of footwear, an upper, a sock liner) may be disposed on the
substrate. In certain embodiments, one or both of the print head
and substrate may be translated along one or more axes and/or
rotated around one or more axes. Translation and/or rotation of the
print head and/or substrate may enable the position of the print
head with respect to the substrate to be changed prior to, during,
and/or after a printing process. In some cases, translation and/or
rotation of the print head and/or the substrate may allow the print
head to deposit material onto a wide variety of substrate surfaces
and/or allow the print head to deposit material onto the substrate
at a wide variety of angles. In some embodiments, the print head
may be configured to be rotated and/or translated such that it can
deposit material onto each surface of the substrate.
[0115] FIG. 20 shows one non-limiting embodiment of a multi-axis
deposition system 1000 comprising print head 1010 and substrate
1020. The print head, substrate, and multi-axis deposition system
will be described in further detail below.
[0116] A print head in a multi-axis deposition system may be any
suitable print head configured to deposit a material of interest
onto the substrate. In some embodiments a multi-axis deposition
system may comprise two or more print heads. Non-limiting examples
of suitable print heads include a direct write head, a mixing
nozzle, an ink jet head, a spray valve, an aerosol jet print head,
a laser cutting head, a hot air gun, a hot knife, an ultrasonic
knife, a sanding head, a polishing head, a UV curing device, an
engraver, an embosser, and the like. In some embodiments, it may be
advantageous for the multi-axis deposition system to comprise a
first print head that is comprises a mixing nozzle and a second
print head that does not comprise a mixing nozzle. As described
elsewhere herein, in some embodiments, the print head may be
configured to accept one or more material inputs (e.g., one
material input, two material inputs, etc.). When two or more
material inputs are present, the inputs may be substantially the
same or they may differ. In some embodiments, the print head may be
configured to mix two or more reactive material inputs to form a
reactive mixture that may be deposited onto a substrate while the
first and second material inputs are reacting and/or after the
first and second material inputs have reacted. For example, the
print head may be configured to mix a polyol and an isocyanate to
form a reactive polyurethane mixture. Other examples of suitable
reactive mixtures include reactive polyurea mixtures, reactive
mixtures comprising reactive polyurethane and reactive polyurea
blends, reactive mixtures comprising epoxy groups and amine groups,
and reactive silicone mixtures.
[0117] A substrate in a multi-axis deposition system may be any
suitable substrate capable of receiving the material deposited by
the print head. In some cases, the substrate may have a shape that
enables facile deposition of the material of interest in a
morphology of interest by the print head. As an example, the
substrate may have a shape that substantially corresponds to the
morphology of interest, such as a footwear last for footwear
applications (e.g., as shown in FIG. 20), a bra cup for sports bra
applications and/or for bra lining applications, an article
substantially corresponding to the shape of a knee for knee brace
applications, an article substantially corresponding to the shape
of an ankle for ankle brace applications, an article substantially
corresponding to the shape of a wrist for wrist brace applications,
an article substantially corresponding to the shape of a shoulder
for shoulder brace applications, and/or an article substantially
corresponding to the shape of an arm for arm band applications. As
another example, the substrate may be a mold or a portion of a
mold. As a third example, the substrate may comprise a portion that
is curved, and/or the substrate as a whole be curved. For instance,
the substrate may have a spherical shape, or a hemispherical shape.
As a fourth example, the substrate may comprise two or more
surfaces that are joined at facets. In some such cases, the
substrate may be a platonic solid or may comprise a portion that is
a platonic solid. In some embodiments, the substrate may be
substantially flat. Other types of substrates are also
possible.
[0118] In some embodiments, a multi-axis deposition system may
comprise a substrate that is removable. The substrate may be
configured to be positioned in the multi-axis deposition system
during material deposition and removed after material deposition.
In some embodiments, a multi-axis deposition system may comprise
multiple substrates that may be added to the multi-axis deposition
system prior to material deposition and/or removed from the
multi-axis deposition system after material deposition. Each
substrate may have a different shape (e.g., a different shoe size,
a different cup size, a mold for a different type of apparel), or
two or more substrates may have substantially the same shape.
[0119] As described above, one or more articles may be disposed on
the substrate prior to material deposition and/or during material
deposition using a multi-axis deposition system. The article(s)
disposed on the substrate may be configured to be positioned on the
substrate during material deposition and, optionally, removed from
the substrate after material deposition. In some embodiments, a
multi-axis deposition system may be configured to deposit material
onto a multiple articles successively, each of which may be added
to the multi-axis deposition system prior to material deposition
and/or removed from the multi-axis deposition system after material
deposition. For example, a textile (e.g., a non-flat textile, an
upper, a woven textile, a knit textile) may be disposed on the
substrate prior to material deposition, during material deposition,
and/or after material deposition. In some embodiments, a multi-axis
deposition system may be employed to deposit a reactive mixture as
described above onto a textile to form a 3D-printed material on the
textile and/or on a succession of textiles sequentially added to
the substrate.
[0120] It should be noted that the print head(s) and the substrate
in a multi-axis deposition system comprising both a print head and
a substrate may be oriented with respect to each other in other
ways than that shown in FIG. 20. As an example, a print head may be
disposed over the center of the substrate in some embodiments and
over the edge of the substrate in other embodiments. As another
example, a print head may be oriented so that it deposits material
on the substrate at a 90.degree. angle to the substrate in some
embodiments and so that it deposits material on the substrate at
another angle to the substrate (e.g., 45.degree., 30.degree., or
other angles) in other embodiments. As a third example, the
substrate may present a bottom surface (e.g., a portion of a last
on which a sole would be disposed) to a print head in some
embodiments and may present a side or top surface (e.g., a portion
of a last on which an upper would be disposed) in other
embodiments. In some cases, the print head(s) and/or the substrate
may be configured to be translated and/or rotated around one or
more axes, as described further below. In such cases, the absolute
positions of the print head(s) and the substrate may be varied
during operation of the multi-axis system, and/or the relative
position of the print head(s) with respect to the substrate may be
varied during operation of the multi-axis system.
[0121] As described above, a multi-axis deposition system may
comprise one or more print heads that may be configured to be
translated along one or more axes. In some embodiments, one or more
print heads may be configured to be translated along one axis,
along two axes, or along three axes. In certain cases, the axes may
be perpendicular to each other. In other cases two or more of the
axes are not perpendicular to each other (e.g., they may intersect
at an angle between 45.degree. and 90.degree.). For example, in
some embodiments the print head may be configured to be translated
vertically, and/or translated in one or more directions
perpendicular to the vertical direction. As another example, in
some embodiments one or more print heads may be configured to be
translated in a direction perpendicular to the substrate, and/or in
one or more directions parallel to the substrate. As a third
example, in some embodiments one or more print heads may be
configured to be translated at a 45.degree. angle with respect to
the substrate. In some cases, each axis of translation may
independently be controlled by separate motors. In some
embodiments, one or more print heads may not be configured to be
translated.
[0122] In some embodiments, one or more print heads in a multi-axis
system may be configured to be rotated around one axis, around two
axes, or around three axes. In some embodiments, one or more print
heads may be configured to be rotated around more than three axes
(e.g., around more than four axes, around more than six axes,
around more than eight axes, around more than 10 axes, or around
more than 12 axes). In certain cases, the axes may be perpendicular
to each other. For example, in some embodiments the print head may
be configured to be rotated around a vertical axis, and/or rotated
around one or more axes perpendicular to the vertical axis. As
another example, in some embodiments one or more print heads may be
configured to be rotated around an axis perpendicular to the
substrate, and/or around one or more axes parallel to the
substrate. In some cases, each axis of rotation may independently
be controlled by separate motors. In some embodiments, one or more
print heads may not be configured to be rotated. In some
embodiments, the print head may be configured to be stationary.
[0123] In some embodiments, a substrate in a multi-axis system may
be configured to be translated along one axis, along two axes, or
along three axes. In certain cases, the axes may be perpendicular
to each other. In other cases two or more of the axes are
perpendicular to each other (e.g., they may intersect at an angle
between 45.degree. and 90.degree.). For example, in some
embodiments the substrate may be configured to be translated
vertically, and/or translated in one or more directions
perpendicular to the vertical direction. As another example, in
some embodiments the substrate may be configured to be translated
in a direction perpendicular to the print head, and/or in one or
more directions parallel to the print head. As a third example, in
some embodiments the print head may be configured to be translated
at a 45.degree. angle with respect to the substrate. In some cases,
each axis of translation may independently be controlled by
separate motors. In some embodiments, the substrate may not be
configured to be translated.
[0124] In some embodiments, a substrate in a multi-axis system may
be configured to be rotated around one axis, around two axes, or
around three axes. In certain cases, the axes may be perpendicular
to each other. In some embodiments, the substrate may be configured
to be rotated around more than three axes (e.g., around more than
four axes, around more than six axes, around more than eight axes,
around more than 10 axes, or around more than 12 axes). For
example, in some embodiments the substrate may be configured to be
rotated around a vertical axis, and/or rotated around one or more
axes perpendicular to the vertical axis. As another example, in
some embodiments the substrate may be configured to be rotated
around an axis perpendicular to the print head, and/or around one
or more axes parallel to the print head. In some cases, each axis
of rotation may independently be controlled by separate motors. In
some embodiments, the substrate may not be configured to be
rotated. In some embodiments, the substrate may be configured to be
stationary.
[0125] In some embodiments, a multi-axis deposition system may
comprise one or more features that aid rotation and/or translation
of a print head and/or a substrate. As an example, in some cases
the print head may be attached to a print head arm that facilitates
motion. When two or more print heads are present, each print head
may be positioned separate print head arms or two or more print
heads may be positioned on the same print head arm. In some cases,
two or more print head arms may be attached to a single gantry. The
print head arms may be capable of facilitating translation and/or
rotation of the print head. In some embodiments, the print head(s)
may be attached to single print head arms; in other embodiments,
the print head(s) may be attached to multiple print head arms that
are attached at joints that allow for rotation and/or translation.
In some cases, one or more motors may facilitate motion of one or
more components of the print head arm(s). As another example, in
some cases the substrate may be attached to a substrate arm that
facilitates motion. The substrate arm may be capable of
facilitating translation and/or rotation of the substrate. In some
embodiments, the substrate may be attached to a single substrate
arm; in other embodiments, the substrate may be attached to
multiple substrate arms that are attached at joints that allow for
rotation and/or translation. In some cases, the substrate may be
attached to a robot arm. In some cases, one or more motors may
facilitate motion of one or more components of the substrate
arm(s). In certain embodiments, the print head may be attached to a
print head arm and the substrate may be attached to a substrate
arm.
[0126] FIGS. 21-23 show various views of a non-limiting embodiment
of a multi-axis deposition system showing various combinations of
axes around which a print head and substrate therein may be
configured to be rotated and/or translated. FIG. 21 shows a
perspective view of the system as a whole, FIG. 22 shows a
cross-sectional view of the system as a whole, and FIG. 23 shows a
close up perspective view of the print head and the substrate. It
should be understood that these figures do not show all possible
combinations of print head and substrate motion, and that all
combinations of print head motion and substrate motion described
above are contemplated.
[0127] In FIGS. 21-23, the multi-axis deposition system includes
print head 1010 and substrate 1020. Print head 1010 in FIGS. 21-23
is attached to first print head arm 1031, which is attached to
second print head arm 1032 by a first print head joint configured
to allow translation of first print head arm 1031 along a first
print head translation axis and along a second print head
translation axis. Second print head arm 1032 is also attached to
gantry 1050, which supports the second print head arm. In some
embodiments, the second print head arm is attached to the gantry by
screws and held in a stationary position (as is shown in FIGS.
21-23). In other embodiments, the second print head arm is
configured to be translated along one or more axes and/or rotated
around one or more axes. The print head may be translated along the
first print head translation axis by translating the first print
head arm along the first print head translation axis, and the print
head may be translated along the second print head translation axis
by translating the first print head arm along the second print head
translation axis. In certain cases, such as that shown in FIGS.
21-23, the second print head arm may be a track along which the
first print head arm may be translated and/or the first print head
joint may comprise a track along which the first print head arm may
be translated. In other embodiments, other types of joints and
print head arms may be employed.
[0128] Substrate 1010 in FIGS. 21-23 is attached to first substrate
arm 1041, which is attached to second substrate arm 1042 by a first
substrate joint configured to allow rotation of first substrate arm
1041 around a first substrate rotation axis. Second substrate arm
1042 is attached to third substrate arm 1043 by a second substrate
joint configured to allow rotation of second substrate arm 1042
around a second substrate rotation axis. The substrate may be
rotated around the first substrate rotation axis by rotating the
first substrate arm around the first substrate rotation axis, and
around the second substrate rotation axis by rotating the second
substrate arm around the second substrate rotation axis. In some
embodiments, one or more of the substrate arms may curved (e.g.,
second substrate arm as shown in FIGS. 21-23). Third substrate arm
1043 is attached to support 1044 by a third substrate joint
configured to allow translation of the third arm along a first
substrate translation axis. The substrate may be translated along
the first substrate translation axis by translating the third arm
along the first substrate translation axis. In certain cases, such
as that shown in FIGS. 21-23, the third substrate arm may be a
track along which the second substrate arm may be translated. In
other embodiments, other types substrate arms may be employed.
[0129] In some embodiments, a multi-axis system may comprise
further features in addition to some or all of those described
above. For example, the multi-axis system may be encased in a frame
or enclosure. FIG. 22 includes frame 1060 with feet 1070 and wheels
1080. The feet may aid stable positioning of the frame on a surface
(e.g., a floor, a desktop, a lab bench). The wheels may promote
facile repositioning of the frame in different locations. In some
embodiments, one or more components (e.g., the frame, one or more
arms) may be formed from standardized parts, such as T-slotted
framing. Other types of standardized parts, and/or non-standard
parts, may also be employed.
[0130] Certain combinations of print head motion and substrate
motion may be especially advantageous. For example, as shown in
FIGS. 21-23, a print head may be configured to be translated
vertically and in a first horizontal direction, and the substrate
may be configured to be translated along a second horizontal
direction perpendicular to the first horizontal direction and
rotated around two distinct axes. As another example, a print head
may be configured to be translated in three perpendicular
directions and the substrate may be configured to be rotated around
two distinct axes. As a third example, a print head may be
configured to be stationary and the substrate may be configured to
be translated in three perpendicular directions and rotated around
two distinct axes. As a fourth example, a print head may be
configured to be translated around three distinct rotation axes and
along three distinct translation axes, and the substrate may be
configured to be stationary. Other combinations of print head
motion and substrate motion are also possible.
[0131] In some embodiments, a multi-axis system may have one or
more features that make it suitable for 3D-printing materials of
interest. For example, the multi-axis system may be configured to
deposit a material onto a substrate as a continuous stream or as a
continuous filament. In other words, the substrate may be in fluid
communication with the print head via the material during
deposition. In certain cases, the multi-axis system may be employed
to deposit a continuous stream or filament that extends from a
first side of a last or a material disposed on the last (e.g., an
upper, a 3D-printed material disposed on an upper) across the
bottom of the last or material disposed on the last to the opposing
side of the last or material disposed on the last. In some cases,
the multi-axis system may be employed to print each portion of an
article of footwear except for the upper.
[0132] In some embodiments, a multi-axis system may be configured
to 3D-print materials with one or more advantageous properties. For
example, the multi-axis system may be configured to 3D-print
materials with a feature size of greater than or equal to 100
microns, greater than or equal to 200 microns, greater than or
equal to 500 microns, greater than or equal to 1 mm, greater than
or equal to 2 mm, greater than or equal to 5 mm, greater than or
equal to 10 mm, greater than or equal to 20 mm, greater than or
equal to 50 mm, greater than or equal to 1 cm, or greater than or
equal to 2 cm. In some embodiments, the multi-axis system may be
configured to 3D-print materials with a feature size of less than
or equal to 5 cm, less than or equal to 2 cm, less than or equal to
1 cm, less than or equal to 5 mm, less than or equal to 2 mm, less
than or equal to 1 mm, less than or equal to 500 microns, or less
than or equal to 200 microns. Combinations of the above-referenced
ranges are also possible (e.g., greater than or equal to 100
microns and less than or equal to 5 cm). Other ranges are also
possible.
[0133] As discussed herein, a 3D printer may be provided that is
capable of printing a material (e.g., a composite) that is formed
by combing two or more other materials (e.g., a polymer and
particles, e.g., reinforcing particles) to create a 3D object, such
as an article of a shoe. Additionally (or alternatively), such 3D
objects may comprise a gradient structure with at least one
non-uniform property (e.g., color, average stiffness, average Shore
A hardness, average pore size, and average density). The inventors
have appreciated that existing techniques for generating printer
instructions for a 3D printer, such as those implemented in
conventional slicer software applications, may be unable to
accurately determine appropriate printer settings (e.g., a ratio of
two or more inputs to a mixing chamber and/or nozzle, a spin speed
of an impeller in the mixing nozzle, sequencing of material into a
mixing chamber and/or nozzle, valving to change material inputs
into the mixing chamber and/or nozzle, total cumulative flowrate of
all inputs to a mixing chamber, vertical position of a print head
relative to the substrate, speed of movement of the print head,
amount of reverse pumping following a movement command, temperature
of the print head, temperature of a substrate onto which the
article is printed, and the calibration setting for a material
inlet pump) to properly print such materials. Accordingly, aspects
of the present disclosure relate to a computer program that is
configured to generate printer settings for printing such materials
in uniform and/or gradient structures of a 3D object.
[0134] The computer program may be configured to receive object
information, such as a design file for a 3D object (e.g., from a
computer-aided design (CAD) program) and/or a print path for
printing a 3D object (e.g., from a slicer application) with
information indicative of target material properties at various
points along the print path, and output print instructions that may
be provided to a 3D printer to accurately create the 3D object. The
computer program may generate the print instructions by, for
example, identifying a target material that is to be deposited,
identifying the input materials required to create the target
material, and identifying the printer settings to print the target
material using the input materials. Once the appropriate set of
printer settings have been identified, print instructions may be
generated using the identified set of printer settings. For
example, print instructions may be generated that comprise a print
path for the print head to follow and printer settings information
indicative of the appropriate printer settings at a plurality of
points along the print path.
[0135] The computer program may comprise a set of instructions that
may be executed by a computer system comprising a processor (e.g.,
a hardware processor or a virtual processor) and a memory (e.g., a
non-transitory computer readable medium). For example, the computer
program may comprise a set of instructions stored in a
non-transitory computer readable medium that programs at least one
processor coupled to the non-transitory computer readable medium.
It should be appreciated that the computer system may be
communicatively coupled to a 3D printer and/or integrated with the
3D printer.
[0136] In some embodiments, the computer program may comprise a
plurality of instructions that program at least one processor to
perform a method 1000 in FIG. 24. As shown, the method 1000
comprises an act 1002 of receiving object information, an act 1004
of identifying target material to be printed, an act 1006 of
identifying input materials to form the target material, an act
1008 of identifying printer settings to print the target material,
and an act 1012 of generating print instructions.
[0137] In act 1002, the system may receive object information
associated with a 3D object. The object information may be, for
example, a design file for a 3D object to be printed. The design
file may comprise information indicative of one or more properties
of the 3D object such as shape, material composition, and/or color.
The design file may be in any of a variety of formats. Example
formats include: Drawing Interchange Format (DXF), COLLAborative
Design Activity (COLLADA), STereoLithography (STL), Initial
Graphics Exchange Specification (IGES), and Virtual Reality
Modeling Language (VRML). Alternatively (or additionally), the
object information may comprise a print path for a print head to
follow to print the 3D object (e.g., generated by a slicer
application) and information indicative of the desired material
properties at various points along the print path. For example, the
object information may comprise a print path comprising a plurality
of points and metadata associated with one or more (or all of) the
plurality of points indicative of a desired material property at
the point (e.g., color, average stiffness, average Shore A
hardness, average pore size, average density, etc.). In some
implementations, the metadata may be directly associated with one
or more points in the plurality of points. In other
implementations, the metadata may be stored in another format and
overlaid onto the print path to determine the material properties
at a given point. For example, the metadata may be desired color
information stored in an image comprising a plurality of pixel
values that may be overlaid onto the print path. In this example,
the pixel value that aligns with a given point in the print path
may be the metadata associated with the respective point.
[0138] In act 1004, the system may identify a target material to be
printed based on the object information. For example, the object
information may comprise information regarding the target material
(e.g., in metadata) and the system may directly identify the target
material from the received object information.
[0139] In act 1006, the system may identify input material(s) to
create the target material. For example, the 3D printer may print
the target material in the object by mixing a first material with a
second material. In this example, the system may identify the first
and second materials. The system may identify this information by,
for example, retrieving information stored in a memory of the
computer system regarding the input materials required to create
the target material in the object.
[0140] In act 1008, the system identifies one or more printer
settings for printing the target material using the identified
input materials. In some embodiments, the system may identify one
or more printer settings required to print the target material at a
plurality of discrete points in the object (e.g., along the print
path). In instances where the printer settings deviate between
discrete points (e.g., to print a gradient structure in the
object), the system may employ interpolation techniques (e.g.,
linear interpolation and cubic interpolation) to smooth shifts in
printer settings between the discrete points. In one example for
illustration, the system may identify that the mixing ratio of two
materials needs to be 40/60 at a first point in a gradient
structure and a 50/50 ratio at a second point in the gradient
structure. In this example, the system may fit a linear curve
between the first and second points to create a smooth ramp between
a 40/60 ratio and a 50/50 ratio. Thereby, the system may create a
set of printer settings to employ along the print path as the print
head moves from the first point to the second point.
[0141] In act 1012, the system may generate the print instructions
using the identified printer settings in act 1008. The print
instructions may comprise, for example, a print path for a print
head to follow to print the 3D object along with printer settings
at a plurality of points along the print path (e.g., generated in
act 1008). The print instructions may be, for example, G-code
instructions. Once the print instructions have been generated, the
system may transmit the print instructions to a 3D printer (and/or
one or more other components of a 3D printer in embodiments where
the computer system is integrated with the 3D printer).
[0142] As mentioned, certain aspects of the present invention
generally relate to the printing of materials, using 3-dimensional
printing and other printing techniques, including the printing of
foams and other materials and/or the modulation of material
composition and material properties through space and/or time. In
some embodiments, a foam may be prepared by mixing materials within
a nozzle, such as a microfluidic printing nozzle, which may be used
to direct the resulting product onto a substrate. The nozzle may be
controlled, for example, using a computer or other controller, in
order to control the deposition of material onto the substrate. In
some cases, gases or other materials may be incorporated into the
material within the nozzle, e.g., to form a foam. However, it
should be understood that the present invention is not limited to
only foams; for example, other materials, including composites that
comprise particles (e.g., reinforcing particles), are also included
in other embodiments of the invention.
[0143] For instance, certain aspects of the invention are generally
directed to devices for 3D-printing. Generally, in 3D-printing,
material is controllably deposited, e.g., on a substrate, to create
a product. The material may be deposited in a pattern defining the
product, or that can be manipulated to create the product, e.g., by
removing portions of the pattern. In some cases, a printing nozzle,
such as a microfluidic printing nozzle, may be used to direct
material onto a substrate. The nozzle may be controlled, for
example, using a computer or other controller, in order to control
the deposition of material onto the substrate.
[0144] One example of an embodiment of the invention is now
described with respect to FIG. 1. As will be discussed in more
detail below, in other embodiments, other configurations may be
used as well. In this figure, a device 10 for printing an article
is shown, using techniques such as 3D printing. The device may
include a nozzle 15, through which material is directed at a
substrate through outlet 18, e.g., through a valve. The substrate
may be planar, or in some cases, the substrate may have a different
shape. The substrate may thus be any suitable target for a material
exiting the nozzle. For instance, the substrate may include a mold
to which the material is applied. Nozzle 15 in FIG. 1 is generally
depicted as being conical or funnel-shaped, although it should be
understood that this is by way of example only, and the nozzle may
have any suitable shape able to direct a material at a
substrate.
[0145] One or more fluids may flow into the nozzle, and in some
embodiments, mixed within the nozzle, e.g., within a mixing chamber
within the nozzle to form the material to be deposited on the
substrate. In some cases, active mixing may be used to mix fluids
within the nozzle. For example, as is shown in FIG. 1, an impeller
20 may be spun to cause mixing within the nozzle. The impeller may
have any size or shape, as discussed below. In some cases, the
impeller, when spun, may substantially conform to the mixing
chamber, or at least a part of the mixing chamber. Thus, for
example, material flowing through the nozzle may be disrupted
through spinning of the impeller (depicted in FIG. 1 as arrow 25),
thereby causing mixing of the material to occur.
[0146] In some embodiments, as discussed herein, the speed of the
impeller may be controlled, e.g., by a computer or other electronic
controller, to control the mixing and/or direction of material
exiting the nozzle. For example, the controller may control a valve
or other apparatus to control the exiting of material from the
nozzle, for example, as the nozzle moves relative to a substrate
(or equivalently, as the substrate moves relative to the nozzle).
Control of nozzle mixing and the position of the nozzle relative to
the substrate may thus be used to control 3D-printing of a material
onto the substrate.
[0147] In addition, in some embodiments, the material within the
nozzle may be subjected to heating or cooling. This may, for
example, be used to control mixing and/or reaction within the
material, to keep the temperature at substantially the temperature
of the surrounding environment (e.g., at room temperature), to
prevent the surrounding environmental conditions and/or the heat
generated by friction of the impeller and exotherm of the material
curing from affecting the reaction or the printing parameters, or
the like. Any method may be used to heat or cool the material
within the nozzle. For example, heating or cooling may be applied
to the nozzle itself, and/or to material within the nozzle.
Non-limiting examples include electrical heating, Peltier cooling,
application of infrared light, or other techniques such as those
discussed herein.
[0148] As mentioned, one or more fluids may enter the nozzle to be
mixed together. The fluids may enter via a common inlet, and/or via
separate inlets, for example, as is illustrated in FIG. 1 with
inlets 31, 32, and 33. Although 3 inlets are illustrated in this
figure, this is by way of example only, and in other embodiments,
more or fewer inlets are also possible. The inlets may
independently be at the same or different distances away from an
outlet of the nozzle. In some cases, the fluids may react upon
contact with each other; thus, the fluids are kept separate prior
to entrance into the nozzle, for example, using one or more inputs
and/or valves to control contact of the fluids with each other. For
example, one or more valves may be present on one or more of the
inlets to control the flow of fluid through the inlets, e.g., into
the nozzle. Examples of valves that can be used include needle
valves, ball valves, gate valves, butterfly valves, or other
suitable types of valves. Additionally, other types of apparatuses
to control fluid flow may also be used, in addition to and/or
instead of valves.
[0149] As a non-limiting example, in one set of embodiments, two or
more fluids may be mixed together to form product on a substrate,
for example, a foam or other article, such as a composite. In some
cases, a material (e.g., a precursor to the foam) may be deposited
on a substrate in a partially fluid state, where the material is
able to harden to form the product on the substrate. For instance,
the material may have a viscosity of less than 1,000,000 cP, less
than 500,000 cP, less than 300,000 cP, less than 100,000 cP, less
than 50,000 cP, less than 30,000 cP, less than 10,000 cP, less than
5,000 cP, less than 3,000 cP, less than 1,000 cP, less than 500 cP,
less than 300 cP, less than 100 cP, less than 50 cP, less than 30
cP, or less than 10 cP. In some cases, the material may have a
viscosity of at least 10 cP, at least 30 cP, at least 50 cP, at
least 100 cP, at least 300 cP, at least 500 cP, at least 1,000 cP,
at least 3,000 cP, at least 5,000 cP, at least 10,000 cP, at least
30,000 cP, at least 50,000 cP, at least 100,000 cP, at least
300,000 cP, at least 500,000 cP, or at least 1,000,000 cP.
Combinations of any of these viscosities are also possible; for
example, the viscosity of a material may be between 100 cP and 500
cP. The material may form a product passively (e.g., upon drying of
the material, completion of a reaction forming the product, etc.),
and/or additional steps may be taken to encourage formation of the
product. As various non-limiting examples, heat may be applied to
the material and/or to the substrate, light (e.g., ultraviolet
light) may be applied to the material to cause a chemical reaction,
etc.
[0150] In some embodiments, a foam may be prepared by mixing a
polymer, a cross-linking reagent, and a cell-forming agent, e.g.,
within a printing nozzle such as is shown in FIG. 1. These may be
added sequentially or simultaneously in various embodiments, e.g.,
as discussed herein. For instance, in FIG. 1, a cross-linking agent
may be added to the nozzle via inlet 31, a cell-forming agent may
be added via inlet 32, and a polymer may be added via inlet 33. In
some cases, these may be flowable at the temperatures in which they
enter the nozzle. In some cases, control of these may be controlled
using one or more valves or other apparatuses on any of these
inlets, optionally controlled by a computer or other controller. In
addition, in some embodiments, one or more of the fluids flowing
into the nozzle may contain particles (e.g., reinforcing
particles).
[0151] One example of a suitable polymer is polyurethane; one
example of a cross-linking reagent is isocyanate; and one example
of a cell-forming agent is water (which can react with the
isocyanate to produce carbon dioxide as the foam forms). Other
examples of each of these are discussed in more detail below. In
addition, it should be understood that other fluids or reactants
may be combined to form a foam, and the invention is not limited to
only embodiments that include a polymer, a cross-linking reagent,
and a cell-forming agent; see below for additional non-limiting
examples. For example, as discussed below, a foam may be prepared
using a polymer and a cell-forming agent, but not necessarily a
cross-linking agent. In some embodiments, other additives may also
be introduced, for example, surfactant, silicone surfactant, UV
stabilizer, catalyst, pigment, nucleation promotors, fillers for
better abrasion resistance, chemical foaming agents, etc. In
addition, other products besides foam may be formed in other
embodiments. For example, in some cases, a composite is formed that
comprises particles (e.g., reinforcing particles); for example, the
composite may include polyurethane or other polymers described
herein, as well as particles (e.g., reinforcing particles) such as
rubber particles. In some cases, the composite is a foam, although
it need not be in other cases.
[0152] As mentioned, if more than two fluids or reactants are used,
they may, in some embodiments, be introduced into the same nozzle,
as is shown in FIG. 1. However, in other embodiments, one or more
of the fluids or reactants may be mixed to form a mixture (for
example, in a first mixing chamber), which can then be mixed with
another fluid or reactant (e.g., in a nozzle such as discussed
herein). A non-limiting example of a two-stage process is shown in
FIG. 2. In this figure, system 10 includes a nozzle 15 and a mixing
chamber 19. First nozzle 15 may be a nozzle such as discussed above
with respect to FIG. 1. For instance, first nozzle 15 may contain
an impeller 20, an outlet 18, and have one, two, or more inputs,
e.g., inputs 31 and 35 as shown in this figure.
[0153] In some cases, one or more of the inputs to first nozzle 15
may be a mixing chamber, such as mixing chamber 19, having an
output 38 which fluidly communicates to inlet 35 of nozzle 15 in
this figure. In some cases, mixing chamber may have a similar shape
to nozzle 15 (e.g., mixing chamber 19 may be a nozzle), although
this is not a requirement. Mixing chamber may have, in some
embodiments, one or more inputs (e.g., inputs 41 and 42). In
addition, in some cases, mixing nozzle 19 may include an impeller
29, or another suitable mixing apparatus. In this example, impeller
29 causes mixing via spinning (depicted in FIG. 1 as arrow 26). The
mixing may be active or passive, and may be the same or different
as in nozzle 15. In some cases, even more stages may be used, in
series and/or parallel, to provide material for input into a
nozzle. For instance, a non-limiting example of a 3-stage serial
process can be seen in FIG. 3. In addition, in some cases, partial
or no mixing of fluids may occur within mixing chamber 19, e.g.,
the fluids may be brought into contact, and some partial or
incidental mixing may occur, while more vigorous mixing may occur
within first nozzle 15.
[0154] A more specific example is provided in FIG. 4. In this
figure, three inputs are provided to a nozzle, e.g., to a mixing
chamber of a nozzle. These inputs are provided by way of
illustration only, and may vary in different embodiments of the
invention. In this figure, a first input may be one or more of a
variety of isocyanates, while a second input may include any one or
more of a variety of inputs, including stabilizers, filler
concentrate, surfactants, diols, triols, multifunctional polyols,
colorants, catalysts, etc. These may be provided as inputs to a
nozzle, in which mixing occurs, as shown in this figure. In some
cases, a cell-forming agent, such as a gas or a blowing agent, may
also be added, and these may be substantially homogenously mixed
together. In some cases, these may form a foam or froth, e.g.,
comprising a plurality of relatively small bubbles of gas dispersed
within a material, e.g., substantially uniformly distributed. This
may then be deposited through the outlet onto a substrate, e.g.,
controlled by a controller, which may control deposition using a
valve or other suitable apparatus. In other cases, as mentioned,
composites or other articles may also be formed.
[0155] The above discussion describes certain non-limiting examples
of various embodiments of the present invention that can be used to
produce 3-dimensionally printed foams and other products (e.g.,
composites), as well as articles made using such techniques.
However, other embodiments are also possible. Accordingly, more
generally, various aspects of the invention are directed to various
systems and methods for 3D-printing foams and other objects as
described herein.
[0156] As mentioned, certain aspects of the invention are generally
directed to foams. Such foams and other articles described herein
may be used in a variety of applications, such as footwear. The
foam, if present, may be a material comprising a matrix and pores
disposed within the matrix. Pores may be randomly distributed
throughout the foam, or may be positioned at regular and/or
pre-determined intervals. The material present within the pores of
a foam is typically of a different phase than the material forming
the matrix of the foam (e.g., a foam may comprise pores that
comprise gas within a matrix that comprises a liquid and/or a
solid). As would be understood to one of ordinary skill in the art,
in a closed-cell foam, the cells of the foam are typically isolated
or separated from each other. By contrast, in an open-cell foam,
the cells of the foam are interconnected with each other; for
example, they may be formed in an interconnected fashion, or the
cells may be ruptured or become interconnected during or after
formation of the foam. These conditions are typically more violent
foaming conditions than those resulting in a closed-cell foam.
[0157] The foam may be formed from a variety of polymers and gases.
The gases may be introduced into materials to form the foam in a
number of ways, including into the foam components prior to
entrance into the mixing nozzle (e.g. frothed components), during
the mixing of components (e.g., active frothing), upon exiting the
print nozzle (e.g. release of pressure or spike in temperature to
generate gas), generated during printing (e.g. water-blown
polyurethanes), generated in a post process after printing is
complete by thermally, or otherwise, activating a chemical additive
within the material (e.g. blowing agent), etc. In addition, in some
cases, a gas may be introduced by providing a liquid that forms a
gas, e.g., upon a decrease in pressure or an increase in
temperature. For instance, a liquid such as butane may be kept
under pressure and/or cooled prior to introduction into the nozzle
or the mixing chamber; a change in temperature and/or pressure may
cause the liquid to form a gas. Without wishing to be bound by
theory, closed cell foams and open cell foams may have different
properties (e.g., closed cell foams may have different values of
density, stiffness, hardness, and the like than otherwise
equivalent open cell foams) and may be suitable for different
applications. In some embodiments, closed cell foams may have
properties that are better suited to footwear applications than
open cell foams.
[0158] In some cases, the foams may be prepared to be lightweight,
tough, elastic, and/or soft, e.g., using techniques such as those
discussed herein. For example, polyurethane foams can be made into
a variety of different applications such as shoe soles, cushions,
pads, insulation, etc. The properties of the foam can be varied
widely, as discussed herein. As an example, similar raw materials
can be used to create a piece of rigid insulation, a memory foam
pillow, a low density elastic foam pad for a seat cushion, or a
high density foam outsole of a shoe. Further non-limiting examples
of 3D printed shoes may be seen in a U.S. provisional patent
application filed on Feb. 27, 2017, entitled "Systems and Methods
for Three-Dimensional Printing of Footwear and Other Articles,"
incorporated herein by reference in its entirety.
[0159] In some cases, foams may be prepared as discussed herein
using various inputs and mixing the inputs using an active mixing
nozzle, as described herein. For instance, the foam density may be
varied by varying the amount of added gas, the amount of added
water (e.g., in water-blown foam applications), the amount of added
blowing agent, etc. As another example, the foam density constant
may be held constant, but the cross-link density or isocyanate
content may be varied to change properties such as the elasticity,
elongation, or stiffness of the foam.
[0160] In some cases, as discussed herein, a foam precursor, prior
to curing, may have different rheological properties than the
starting raw materials without gas content. For example, a mixture
of low viscosity fluids, gases, and/or surfactants, etc. having
Newtonian flow behavior before foaming can be used to produce a
precursor having non-Newtonian flow characteristics, e.g., with a
yield stress, or shear-thickening or shear-thinning behavior. This
may be used herein to produce a precursor having a rheological
profile suitable for printing, e.g., on a substrate. Fluids such as
incompressible Newtonian fluids or gases can be introduced into a
nozzle (e.g., prior to mixing) in a controlled fashion and
precisely metered onto a substrate during deposition. In some
cases, the foaming process may start within the nozzle, and this
process may affect the final mechanical properties of the foam.
[0161] Accordingly, certain aspects are generally directed to
systems and methods for producing a foam or other products as
discussed herein. In some cases, a foam may include a plurality of
cells (which may include open and/or closed cells) within a polymer
or other suitable matrix. Accordingly, certain embodiments
described herein are directed to systems and methods able to
3D-print a material on a substrate that is able to form a foam. For
instance, the material, at 3D-printing, may have properties that
allow it to flow, e.g., from a nozzle, onto a substrate. The
material may also contain a gas therein (and/or a gas precursor)
that can form the cells of the foam, e.g., upon solidification of
the material to form the foam.
[0162] In some embodiments of the invention, a material is formed
via mixing of two, three, or more fluids to form a precursor, which
is 3D-printed onto a substrate and allowed to solidify to form a
foam or other product, such as a thermoplastic, an elastomer, a
rigid thermoset, or the like. A variety of fluids may be reacted to
form a precursor to the foam, as is discussed in further detail
herein. In some embodiments, a microfluidic printing nozzle is used
to prepare the material prior to deposition onto a substrate. In
some embodiments, more than one fluid may be introduced into the
nozzle, and the fluids can be mixed within the nozzle to produce
the material to be deposited onto the substrate.
[0163] In one set of embodiments, a nozzle is used to direct a
material (e.g., a precursor) onto a substrate. The nozzle can have
any suitable shape. The nozzle may have any suitable shape having
an outlet able to direct material at a substrate. For instance, the
nozzle may be conical, pyramid-shaped, funnel-shaped, cylindrical,
or the like. The nozzle may also have any suitable size. In some
cases, the nozzle may include one or more mixing chambers or other
regions in which two fluids come into contact with each other, and
can be mixed together, e.g., actively or passively. The nozzle or
the mixing chamber may have a volume that is less than 20 ml, less
than 18 ml, less than 16 ml, less than 14 ml, less than 12 ml, less
than 10 ml, less than 8 ml, less than 6 ml, less than 5 ml, less
than 4 ml, less than 3 ml, less than 2 ml, less than 1 ml, less
than 0.5 ml, less than 0.3 ml, less than 0.1 ml, etc., and/or a
volume that is at least 0.1 ml, at least 0.3 ml, at least 0.5 ml,
at least 1 ml, at least 2 ml, at least 3 ml, at least 4 ml, at
least 5 ml, at least 6 ml, at least 8 ml, at least 10 ml, at least
12 ml, at least 14 ml, at least 16 ml, at least 18 ml, at least 20
ml, etc.
[0164] In addition, fluids may be introduced into the nozzle, and
product produced within the nozzle, at relatively high rates. For
example, in certain embodiments, the rate of printing of product
may be at least 0.1 mL/min, at least 0.3 mL/min, at least 0.5
mL/min, at least 1 mL/min, at least 3 mL/min, at least 5 mL/min, at
least 10 mL/min, at least 30 mL/min, at least 50 mL/min, at least
100 mL/min, at least 300 mL/min, at least 500 mL/min, at least 1
L/min, at least 3 L/min, at least 5 L/min, at least 10 L/min, or at
least 20 L/min. In some cases, the rate of printing may be no more
than 25 L/min, no more than 20 L/min, no more than 15 L/min, no
more than 10 L/min, no more than 5 L/min, no more than 3 L/min, no
more than 1 L/min, no more than 500 mL/min, no more than 300
mL/min, no more than 100 mL/min, no more than 50 mL/min, no more
than 30 mL/min, no more than 10 mL/min, no more than 5 mL/min, no
more than 3 mL/min, no more than 1 mL/min, no more than 0.5 mL/min,
no more than 0.3 mL/min, or no more than 0.1 mL/min. Combinations
of any these are also possible, e.g., the rate of printing may be
between 5 L/min and 20 L/min. In addition, as discussed above, a
fluid may contain particles (e.g., reinforcing particles) in some
cases. In some cases, particles such as reinforcing particles can
be introduced into the nozzle, e.g., without the presence of a
fluid. For example, the particles (e.g., reinforcing particles) may
enter the nozzle in a substantially dry state in certain
embodiments.
[0165] Relatively small volumes such as these may be useful in
certain embodiments to promote more complete mixing, e.g., such
that the fluids and/or solids are substantially mixed together,
and/or to promote smaller residence times within the mixer, for
example, less than 30 s, less than 25 s, less than 20 s, less than
15 s, less than 10 s, or less than 5 s. In addition, relatively
small volumes may be useful to more rapidly stop and/or alter the
reactants (and/or additives, if present) within the nozzle or
mixing chamber. In some instances, a smaller volume may be easier
to control and/or alter the degree of mixing, e.g., to compensate
for variable flowrates and system reactivities, or the like.
[0166] As mentioned, in certain embodiments of the invention, the
nozzle may include a valve, such as a needle valve. In some cases,
a valving system may be used to control fluid input into the nozzle
and/or material exiting the nozzle. In certain instances, various
components of the mixing system that come in contact with the
material may be set up with a valving system.
[0167] The fluids and/or particles (if present) may be mixed until
they are substantially mixed together in certain embodiments, e.g.,
having a relatively uniform appearance, or are substantially
homogenous mixed. For instance, the fluids and/or particles (if
present) may be mixed such that the individual fluids are evenly
distributed relative to each other (e.g., upon exiting the nozzle).
In some cases, after mixing, portions of the exiting mixture do not
exhibit large or changing variations in relative distributions or
ratios of one fluid relative to other fluids. However, in other
cases, the fluids and/or particles (if present) may only be
partially mixed together. In some cases, mixing within the nozzle
may be passive, e.g., where the flow of fluids and/or particles (if
present) into the nozzle causes the mixing of the fluids and/or
particles within the nozzle. The nozzle may also contain, in some
embodiments, baffles or other impediments to disrupt the flow of
fluid and/or particles, e.g., to promote mixing.
[0168] As one non-limiting example, the geometry of the nozzle can
be determined in certain embodiments for a given material set and
flow rate such that the material exits the nozzle with a viscosity
higher than the viscosities of any of the individual inputs but has
not yet solidified. For instance, various polyols and the
isocyanates can be selected to tune the material reactivity to suit
the flow rate into the nozzle and the mixing volume, such that the
materials begin to react as they are mixed and also remain fluid
enough to be able to leave the nozzle at the outlet continuously.
Other parameters, such as a catalyst or the temperature, may also
be used to tune material reactivity. Non-limiting examples of
methods of heating or cooling a nozzle are discussed in more detail
below.
[0169] In some embodiments, material exiting the nozzle may pass
through an opening which structures the printed line (e.g.
continuously printing) or dose (e.g. dosing mode). The opening can
be one of a variety of geometries including, but not limited to,
circular, rectangular, star-shaped, any closed two-dimensional
shape, multiple separate shapes (e.g., being fed from the same
nozzle), or the like.
[0170] In addition, in some embodiments, the nozzle, mixing
chamber, and/or the impeller may be at least partially coated with
a non-stick surface to prevent material from building up on such
surfaces. Examples of suitable coatings include, but are not
limited to, polymeric coatings such as polyurethane or epoxy
coatings, or ceramic coatings.
[0171] One non-limiting example of an architecture for a nozzle can
be seen in FIG. 11. In this figure, a plurality of mixing units may
be used to mix various fluids, and such mixtures, and/or a purge
fluid, may be combined within a mixing chamber (e.g., within a
nozzle), along with gas (for example, from a suitable source, such
as a pressurized gas tank, controlled using a flow regulator, a
valve, or another suitable system. The product, after mixing, may
be controllably released through a valve to an outlet, and/or
purged (for example, when different materials are mixed, as
discussed herein). An example of a material mixing unit can be seen
in FIG. 12. A plurality of different pumping systems may be used to
combine two or more fluids together within a mixing unit.
[0172] Examples of architectures for various subsystems in certain
embodiments of the invention can be seen in FIG. 13. In FIG. 13A,
an example architecture for a pumping subsystem is shown. Material
may be controlled by a pump and/or a valve, and optionally
monitored by a flowmeter or other suitable sensor, e.g., as
discussed herein. FIG. 13B illustrates the architecture for a
mixing chamber. This may include, for example, one or more inputs
(e.g., a gas input or a fluid input), various sensors to for
example, inspect or measure mixing, a controller to control the
impeller, e.g., the speed and/or position, etc., which may lead to
one or more outputs, e.g., a material output and a purge
output.
[0173] It should be noted that these architectures are by way of
example only, and in other embodiments, other architectures may be
used, for example, for nozzles, mixing chambers, pumping
subsystems, or the like.
[0174] In addition, in some embodiments, the composition or one or
more of the fluids and/or particles (if present) may be changed
during the mixing process, e.g., to produce a change or a gradient
in properties in the product. For example, the ratio of two
reactants may be changed during mixing, or one reactant may be
replaced with another reactant during mixing, etc. In some cases, a
first fluid may be changed to a different fluid in a continuous
manner, e.g., without interruption. As another non-limiting
example, particles (e.g., reinforcing particles) may be added to
the nozzle and/or to a fluid entering the nozzle, and changed to
different particles (e.g., reinforcing particles), e.g., without
interruption.
[0175] Non-limiting examples of properties that may change within a
product include pore or cell size, density, stiffness, hardness,
degree of cross-linking, chemical composition, or the like. The
change may be a step change, or a more gradual change, e.g.,
producing a gradient in a property. For example, a foam or other
product may exhibit a first portion having a first property (e.g.,
average pore size) and a second portion having a second property.
Thus, for example, the product may have a first average pore size
and a second portion that solidifies into a foam having a second
average pore size, wherein the first average pore size is at least
10%, at least 20%, at least 30%, at least 40%, at least 50%, etc.
greater than the second average pore size. There may be a gradual
or abrupt change between the portions. Other examples of properties
that may change within a product include, but are not limited to,
average largest dimension of particles (e.g., reinforcing
particles), average concentration of particles (e.g., reinforcing
particles), surface roughness, compression strength, slip
resistance, and abrasion resistance.
[0176] As used herein, a portion of an article may refer to any
collection of points within the article (i.e., points that are
within the portion of space bounded by the external surfaces of the
article). Portions of the article are typically, but not always,
volumes of space within the article (in some embodiments, a portion
may be a surface within an article, a line within an article, or a
point within an article). Portions of the article may be continuous
(i.e., each point within the portion may be connected by a pathway
that does not pass through any points external to the portion) or
may be discontinuous (i.e., the portion may comprise at least one
point that cannot be connected to at least one other point within
the article by a pathway that does not pass through any points
external to the portion). Portions of an article may be
substantially homogeneous with respect to one or more properties
(e.g., one or more properties of the portion may vary with a
standard deviation of less than or equal to 1%, 2%, 5%, or 10%
throughout the portion), and/or may be heterogeneous with respect
to one or more properties (e.g., one or more properties of the
portion may vary with a standard deviation of greater than or equal
to 1%, 2%, 5%, or 10% throughout the portion).
[0177] In some embodiments, one or more properties of a mixture
that is 3D-printed from a nozzle may change as a function of time
and/or nozzle position with respect to the substrate. For instance,
the composition of one or more components and/or the wt % of one or
more components within the mixture may change as a function of
time. In some embodiments, one or more physical parameters of the
nozzle and/or the substrate may change as a function of time. As an
example, the temperature of the nozzle and/or the substrate may
change as a function of time. Without wishing to be bound by
theory, the temperature of the nozzle and the temperature of the
substrate may affect the types of reactions that occur between
various components (e.g., cross-linking reactions, foaming
reactions, reactions within the nozzle, reactions on the substrate)
and/or the rates at which these reactions occur. This may in turn
affect the chemical structure of the mixture (e.g., the composition
of the mixture, the degree of cross-linking of the resultant foam)
during and/or after printing, and/or affect one or more physical
properties of the mixture (e.g., the viscosity of the mixture, the
average pore size of the resultant foam, the density of the
resultant foam, the stiffness of the resultant foam, the hardness
of the resultant foam) during and/or after printing. In some
embodiments, changes in substrate or nozzle temperature during
printing may allow for different portions of the 3D-printed article
(e.g., those printed at different times and/or in different
positions on the substrate) to have different chemical or physical
properties. In some embodiments, the portions with different
chemical and/or physical properties may be printed in a single
continuous process, and/or may together form a single integrated
material.
[0178] In one set of embodiments, active mixing processes may be
used to mix the fluids. For example, an impeller or other mixing
apparatus may be used to mix fluids within the nozzle, e.g., in a
mixing chamber within the nozzle. (However, it should be understood
that an impeller is not necessarily required in all embodiments.)
The impeller, if present, may have any shape or size able to cause
the mixing of fluids. For instance, the impeller may include one or
more vanes, blades, propellers, paddles, holes, and/or cavities, or
the like, which may be used to cause movement (e.g., spinning) of
fluids within the nozzle. In one embodiment, an impeller may
include internal channels that allow a gas or fluid to enter
through the impeller into the mixing chamber or nozzle. For
instance, the nozzle may include a spindle having one or more
openings that allow gas or other fluids to be released.
[0179] In addition, the impeller may be fabricated out of any
suitable material, e.g., metal, ceramic, a polymer, or the like. In
some cases, the impeller itself may be 3D-printed. The impeller may
be controlled using any suitable technique, e.g., by mechanically,
electrically, and/or magnetically the impeller. In some cases, more
than one impeller or other mixing apparatus may be used.
Non-limiting examples of other mixing apparatuses and techniques
include turbines or the application of ultrasound or additional
fluids into the nozzle.
[0180] In addition, in some cases, no impeller or other mixing
apparatus is used; for example, passive mixing techniques, such as
controlling channel geometries or input flows, may also be used.
For instance, ratios and/or compositions of incoming fluids may be
controlled to control mixing, e.g., within a nozzle or mixing
chamber. Combinations of mixing systems may also be used in certain
embodiments, including combinations of active systems, or
combinations of active and passive systems, for example, including
any of the active or passive systems described herein.
[0181] In some cases, an impeller (or other mixing apparatus) may
sweep through the nozzle or the mixing chamber such that the
closest distance between the impeller as it travels and the wall of
the nozzle or mixing chamber is less than 10 mm, less than 5 mm,
less than 3 mm, less than 1 mm, less than 0.5 mm, less than 0.3 mm,
less than 0.1 mm, less than 0.05 mm, less than 0.0.3 mm, less than
0.01 mm, less than 0.005 mm, etc. In some cases, the impeller may
come into contact with the wall, although in other cases, the
impeller may be at least 1 mm, at least 3 mm, at least 5 mm, or at
least 10 mm away from the wall as it travels. In some cases, the
impeller or other mixing apparatus may be one that substantially
conforms to the shape of the nozzle or the mixing chamber in which
the impeller or other mixing apparatus is located. For instance,
the impeller may, upon rotation, sweep through a volume that is at
least 50%, at least 60%, at least 70%, at least 80%, at least 90%,
or at least 95% of the volume of the nozzle or the mixing
chamber.
[0182] The impeller, if used, may be rotated at any suitable speed.
For example, the impeller may be rotated at a speed of at least 5
rpm, at least 10 rpm, at least 20 rpm, at least 30 rpm, at least 40
rpm, at least 50 rpm, etc. In some cases, much higher rotation
speeds may be used, e.g., at least 100 rpm, at least 200 rpm, at
least 300 rpm, at least 500 rpm, at least 750 rpm, at least 1000
rpm, at least 2000 rpm, at least 3000 rpm, at least 5000 rpm, at
least 7500 rpm, or at least 10,000 rpm. Higher rpm speeds may be
useful in certain embodiments to create a froth or a foam. In some
(but not all) embodiments, the impeller may be rotated at an rpm
speed that is at least 16 times the residency time of the material
in the mixing chamber or the impeller (for example, if the
residency time is 10 seconds, then the rpm speed may be at least
160 rpm). In some cases, the impeller may be rotated at variable
speeds. For instance, the impeller may be rotated at different
speeds to control the formation or various properties of the foam
or other product, and/or the impeller may be rotated to control the
rate at which a material is deposited onto a substrate from the
nozzle. In addition, in some cases, the impeller may be rotated at
a speed that increases or decreases with respect to time. In some
cases, changing the rotation speed of the impeller with respect to
time may be used to alter a property of the foam or other product,
e.g., from a first portion to a second portion. An example of a
system that can be used to control the speed of the impeller can be
seen in Int. Pat. Apl. Pub. No. WO 2016/164562, incorporated herein
by reference.
[0183] In addition, in some embodiments, the impeller may be at
least partially coated with a non-stick surface to prevent material
build-up, as discussed herein.
[0184] In some cases, the impeller shape has a shape that allows it
to fill the majority of the volume of the mixing chamber, such that
the mixing volume is relatively small. When the mixing volume is
relatively small, the material may have a relatively short
residency time in the mixer, and the material properties or
gradient structures can be varied quickly. In some cases, the free
volume of the mixing chamber or nozzle (i.e., the volume therein
not occupied by the impeller) may be less than 20 ml, less than 18
ml, less than 16 ml, less than 14 ml, less than 12 ml, less than 10
ml, less than 8 ml, less than 6 ml, less than 5 ml, less than 4 ml,
less than 3 ml, less than 2 ml, less than 1 ml, less than 0.5 ml,
less than 0.3 ml, less than 0.1 ml, etc. Thus, for example, in some
embodiments, the impeller has a conical shape, e.g., if the mixing
chamber or nozzle has a conical shape. In addition, in some cases,
the impeller may be positioned such that the impeller as it travels
has a distance from the wall of the nozzle or mixing chamber as
discussed herein.
[0185] In one set of embodiments, the position of the impeller can
be controlled or altered, for example, before or during mixing. The
impeller may be actuatable with respect to the position of the
mixing chamber, e.g., such that the mixing volume can be changed at
any point to account for variable flowrate, thus keeping the
residency time in the mixing chamber constant. For example, an
actuator or servo may be able to move the impeller laterally within
the mixing chamber, or towards an outlet, for example, during
mixing or rotation of the impeller. In addition, in some cases, the
impeller speed can be varied, such that the material experiences a
fixed number of impeller rotations per residency time in the mix
chamber.
[0186] In certain embodiments, the impeller can be used as a valve.
For example, the end of the impeller may be directed into the
outlet of the nozzle to block and close the nozzle, thereby
preventing or controlling flow out of the chamber. For instance,
the impeller may be directed forward (into the outlet) to prevent
flow, and/or moved various distances relative to the outlet to
allow different flows of fluid out of the nozzle.
[0187] In one set of embodiments, the nozzle and/or the mixing
chamber may be heated or cooled. In some cases, the temperature of
mixing may be controlled, for instance, to allow for uniform
mixing, to facilitate reaction of fluids therein (e.g., to an
optimum or desired temperature), to remove excess heat (e.g.,
contributed by a chemical reaction, the spinning of an impeller,
etc.), or the like. Various methods can be used to add heat or
remove heat from the nozzle or the mixing chamber. For example, a
heat source may be positioned to deliver heat to the nozzle or
mixing chamber, or to one or more fluids entering therein. Examples
of heat sources include electrically resistive heaters, infrared
light sources, or heating fluids (e.g., which can transmit heat
using a heat exchanger or the like). In some cases, more than one
heat source may be used. Similarly, a variety of cooling sources
can be used in some embodiments to remove heat from the nozzle or
mixing chamber. Non-limiting examples include Peltier coolers or
cooling fluids (e.g., which can remove heat using a heat exchanger
or the like).
[0188] Heating and/or cooling may, for example, be used to control
mixing and/or reaction within the material, to keep the temperature
at substantially the temperature of the surrounding environment
(e.g., at room temperature), to prevent the surrounding
environmental conditions and/or the heat generated by friction of
the impeller and exotherm of the material curing from affecting the
reaction or the printing parameters, or the like. In some cases,
the temperature may be altered by at least 5.degree. C., at least
10.degree. C., at least 15.degree. C., at least 20.degree. C., or
by other ranges such as those discussed herein. In other
embodiments, however, the temperature may be controlled or altered
by no more than 20.degree. C., no more than 15.degree. C., no more
than 10.degree. C., no more than 5.degree. C., etc. relative to the
incoming fluids or the surrounding environmental conditions.
[0189] In addition, in some embodiments, one or more sensors may be
present, e.g., within the nozzle or mixing chamber, within an
outlet, within the substrate, or within sensing communication of
the nozzle, mixing chamber, outlet, and/or substrate. Such sensors
may be used to determine a property of the incoming fluids, the
mixing process, and/or the exiting material (for example, the
flowrate), e.g., qualitatively and/or quantitatively. In some
cases, such information may be used to control the process, e.g.,
by controlling the flow of fluid into the nozzle or mixing chamber,
the mixing speed (e.g., of an impeller), the flow exiting an
outlet, the opening and closing of a valve at the outlet, or the
like. Non-limiting examples include temperature sensors (e.g.,
thermocouples, infrared cameras, or the like), pressure
transducers, photodiodes, colorimetric sensors, etc. In addition,
more than one sensor can be used in some cases.
[0190] Fluid, or solid particles, or a semi-solid paste, may be
introduced into the nozzle or mixing chamber from one, two, three,
or more inputs, in one set of embodiments. The inputs may
independently have the same or different distances from the outlet
of the nozzle or mixing chamber. As an example, two inputs may be
near the top of a nozzle or mixing chamber, e.g., to allow two
fluids to mix, and additional inputs may be lower, e.g., to
introduce additional components (for instance, additives) as the
fluids flow down the mixing chamber. As various non-limiting
examples, this may be useful to allow reactions to occur in a
certain order, to build viscosity first before starting to foam, to
mix surfactants before adding filler, to mix ingredients prior to
adding a catalyst, or the like.
[0191] In some embodiments, one or more of the inlets may be
controlled using one or more valves or other apparatuses. In some
cases, the valves may be controlled using a computer or other
controller, e.g., as discussed herein. Thus, for example, valves
may be used to control flow into (and/or out of) the nozzle. In
some cases, valves may be used to control the flow of fluids
through channel intersections, e.g., to keep fluids from reacting
or curing too early (e.g., by creating a cured skin at the
interface of an inactive channel). Examples of valves that can be
used include, but are not limited to, needle valves, ball valves,
gate valves, butterfly valves, and the like. The valves can
independently be controlled, e.g., by electrical actuation,
pneumatic actuation, or the like. In addition, in some cases, an
impeller (if present) may be used as a needle valve, e.g., in
conjunction with an outlet, as discussed herein.
[0192] The entering fluid may be gas, a liquid, a viscoelastic
material, and/or any other flowable or deformable material. In some
cases, the fluid may also contain particles such as particles
(e.g., reinforcing particles), including those discussed above. In
addition, the entering fluid may include combinations of any of
these in certain embodiments. In some cases, two or more fluids may
be mixed prior to delivery, e.g., as discussed in detail herein.
However, in some cases, two or more fluids may not be mixed prior
to delivery. For instance, two or more inlets into the nozzle or
mixing chamber may be used to introduce two or more separate
fluids. These fluids can then be mixed in the nozzle or mixing
chamber.
[0193] The fluids may be delivered using any suitable technique,
and the same or different techniques may be used to delivery
different fluids. For instance, fluids may be delivered passively
(i.e., by gravitational flow), or actively (for example, by using
pumps such as progressive cavity pumps, auger pumps, gear pumps, or
the like). In some embodiments, the fluids may delivered using
input channels that may have features to create turbulent flow
and/or to cause passive mixing, e.g., as fluid flows through the
channels. This may be useful, for example, in causing some mixing
(for example, of a fluid with an additive) in order to occur prior
to entry into a nozzle or mixing chamber such as described herein.
In some cases, as mentioned, the nozzle may also include particles
such as reinforcing particles, which may be incorporated into the
final product, e.g., as a composite material.
[0194] In some cases, active mixing may be used to control the
delivery of different fluids and/or particles (if present). This
may be useful, for example, for mixing fluids entering in at
different flowrates (e.g., as in a 4:1 or 10:1 ratio), different
viscosities, or the like. For example, in some cases, fluids that
may be used include fluids that have relatively high viscosities,
or viscoelastic solids that exhibit a yield stress, etc.
[0195] In some cases, a gas and a liquid may be mixed within the
nozzle, e.g., as discussed above, to produce a froth. The gas may
be added to the nozzle, and/or generated within the nozzle. The
froth may comprise bubbles or pockets of gas dispersed within the
fluid. The bubbles within the froth may be dispersed relatively
uniformly or homogenously, or may have a relatively small average
size. For example, the average bubble size within the froth may be
less than 10 mm, less than 5 mm, less than 3 mm, less than 1 mm,
less than 500 micrometers, less than 400 micrometers, less than 300
micrometers, less than 200 micrometers, less than 100 micrometers,
less than 50 micrometers, less than 30 micrometers, less than 10
micrometers, less than 5 micrometers, etc. in average or
characteristic diameter and/or the average bubble size may be at
least 1 micrometer, at least 2 micrometers, at least 3 micrometers,
at least 4 micrometers, at least 5 micrometers, at least 10
micrometers, at least 30 micrometers, at least 50 micrometers, at
least 100 micrometers, at least 300 micrometers, at least 500
micrometers, at least 1 mm, at least 3 mm, at least 5 mm, etc. The
bubbles may also exhibit a relatively uniform distribution of
sizes, for example, such that at least 80%, at least 90%, or at
least 95% of the bubbles within a sample of froth have an average
diameter that is between 80% and 120%, or between 90% and 110% of
the average bubble diameter. The gas may be introduced as one of
the fluids entering the nozzle, and/or generated through chemical
reaction of fluids within the nozzle. Non-limiting examples of
gases that may be used include air, carbon dioxide, nitrogen,
argon, or the like. In some cases, the froth may be deposited onto
a substrate, e.g., as discussed herein. The froth may, in some
embodiments, comprise at least 20%, at least 30%, at least 40%, or
at least 50% by volume of gas. In addition, in some cases, the
froth may also contain particles (e.g., reinforcing particles).
[0196] In some cases, the nozzle may include more than one fluid
that can be mixed with the gas. For example, in one embodiment,
reactive fluids or fluids that contain surfactants that facilitate
the introduction of the gas as bubbles in the fluids may be used.
Examples of surfactants are discussed in more detail below. In some
cases, mixing may occur relatively rapidly (for example, by
spinning the mixing impeller at high velocity), and the froth would
be in its near final form upon exiting the mixing nozzle. The froth
may then be deposited or hardened to form a foam. The density of
the froth (or the subsequent foam) can be varied by varying the
ratio of the gas to the liquid. The mean bubble size in the froth
(or the foam) can be varied, for example, by changing the impeller
rotational velocity and/or the residence time in the nozzle or
mixing chamber. The mechanical properties of the foam can also be
changed, for example, by varying fluid compositions entering the
nozzle during the formation process (for example, the ratio of
isocyanate to polyol).
[0197] In some cases, producing froths or other materials
containing gas within the nozzle, e.g., by mixing within the
nozzle, may allow control over the froth or subsequent product that
is formed. For instance, rheological properties may be controlled
or altered by controlling mixing and/or the introduction of fluids
within the nozzle. Froth development also may be at least somewhat
independent of reaction rates, as it can be partially controlled by
controlling external factors such as the mixing rate, e.g., at
least in embodiments where no gas is produced by reaction (although
in other embodiments, gases that contribute to the froth may
desirably be produced by reaction).
[0198] In one set of embodiments, a material (for example, a
froth), when deposited onto a substrate, may have a variety of
rheological properties. For instance, the material may be
substantially fluid and able to flow, e.g., to conform a mold or
other substrate to which it is deposited. In some cases, the
material may have a viscosity of less than less than 1,000 cP, less
than 500 cP, less than 300 cP, less than 100 cP, less than 50 cP,
less than 30 cP, or less than 10 cP. The material may also be
Newtonian or non-Newtonian. In other embodiments, however, the
material may exhibit some degree of solidity or elasticity, e.g.,
having a non-zero yield stress, and/or by exhibiting at least some
resistance to a distorting influence or deforming force that is
applied to the material. In some cases, the material may be
sufficiently solid as to be able to define or hold a shape. For
instance, the material may be sufficiently solid such that it
deforms from its original shape by less than 10% (by volume) after
deposition on a substrate, e.g., within 30 seconds after printing
onto the substrate.
[0199] The substrate may be any suitable target for a material
exiting a nozzle. In some cases, the substrate is planar, although
in other cases, the substrate is non-planar. For instance, the
substrate may be a mold (e.g., the mold of a shoe), to which a
material may be introduced. In some cases, the material may be
relatively fluid and able to conform to contours within the
substrate (e.g., if the substrate is a mold). However, in other
cases, the material may be relatively solid, e.g., having a defined
shape, upon deposition onto the substrate, such as is discussed
herein.
[0200] In some cases, the substrate may also be heated or cooled,
e.g., to promote or inhibit a reaction, to cause solidification to
occur, or the like. In some cases, the temperature may be altered
by at least 5.degree. C., at least 10.degree. C., or by other
ranges such as those discussed herein. Any method may be used to
heat or cool the substrate. For example, heat or cooling sources
may be used to apply heat or cooling to the substrate, the
substrate may be contained within a heated or cooled environment,
or a source of a heated or cooled fluid may be used to heat or cool
the substrate, e.g., via a heat exchanger). In one embodiment,
radiant light or infrared radiation may be applied to the substrate
for heating.
[0201] As a non-limiting example, in one embodiment, a two-stage
foaming system that implements two foaming types may be used. For
example, using mechanical frothing in the nozzle may be used to mix
a Newtonian liquid with a blowing agent into a printable
viscoelastic foam formulation. After deposition, the polymer in the
foam may be completely or partly cured. The temperature of the
polymer can be raised to drive the decomposition of the blowing
agent, and the subsequent expansion of the foam.
[0202] As another non-limiting example, a nozzle involving
mechanical frothing may be used to create a foam having a yield
stress that behaves viscoelastically. After deposition, the foam
may be heated to achieve further expansion of the foam. This
secondary expansion can be carried out, for example, using an
agent, such as azodicarbonamide. For example, one or more inputs
can be used to deliver a polyol loaded with surfactant and a
blowing agent into a nozzle, which are then mixed together, e.g.,
such that a froth is formed.
[0203] In some aspects, two or more fluids may be mixed prior to
introduction into a nozzle. In some cases, the fluids may be mixed
in a second nozzle or mixing chamber (e.g., separate from the first
nozzle), and in some cases, a series of mixing chambers may be
used, in any arrangement, e.g., in series and/or parallel. Thus, in
some embodiments, more than one stage of mixing or combining fluids
may be used. As non-limiting example, FIG. 2 shows a mixing chamber
that outputs into an input of a printing nozzle, while FIG. 3 shows
two mixing chambers in series with a printing nozzle. In one set of
embodiments, the mixing chambers may be in nozzles similar to the
printing nozzles described herein, e.g., having any of the
dimensions described herein with respect to printing nozzles, and
optionally with an impeller, e.g., as described herein with respect
to printing nozzles. However, in other embodiments, the mixing
chambers may have substantially different shapes and/or sizes. If
two, three, or more impellers are present, the impellers may be
independently controlled in some instances.
[0204] Mixing within a mixing chamber may be relatively complete,
or may be partial in some cases. In addition, in some cases, no
mixing may occur in a mixing chamber, other than incidental mixing
or diffusion (for example, as two fluids come into contact with
each other). As noted above, more vigorous mixing can occur within
the printing nozzle, which may lessen the need for complete mixing
to occur upstream. However, in other embodiments, more complete
mixing may occur within one or more mixing chambers upstream of the
printing nozzle.
[0205] In some aspects, one or more purge fluids may be used to
purge one or more of the inlets, outlets, nozzles, and/or mixing
chambers, etc. For example, a purge fluid may be passed through one
or more of these when they are not actively being used to mix or
print, and/or to clear fluids so that different fluids can be used.
For instance, a purge fluid may flow through an inlet when
switching the inlet from a first fluid source to a second fluid
source, e.g., to purge residual fluid from the first fluid source
that may be present. The purge fluid may flow through the nozzle in
some cases, and/or be removed prior to the nozzle. Non-limiting
examples of purge fluids include gases such as air, carbon dioxide,
nitrogen, argon, or the like, and/or liquids such as water (which
may be pure, contain one or more additives such as surfactants in
some cases, etc.). Purge fluids could also be a non-reactive paste
such as petroleum jelly or a viscous silicone oil or paraffin wax,
or an aqueous or alcohol based gel such as pluronic or carbopol.
Combinations of purge fluids may also be used in some
embodiments.
[0206] As a non-limiting example of use of a purge fluid, a nozzle
may have a first inlet and a second inlet, in which two fluids (A
and B) are reacted together to produce a first product. The nozzle
may also be used to produce a second product also formed from two
fluids (A' and B'), where one or both of A' and B' are different
than A and B. Both A and A' may be introduced using the first
inlet, while B and B' may be introduced using the second inlet. To
avoid contamination of A with A' and/or B with B', one or more
purge fluids may be introduced between introducing A and A' to the
nozzle and/or B and B' to the nozzle. In some cases, sufficient
purge fluid may be introduced to clear the entire nozzle or mixing
chamber between different fluids, although in other cases, some
degree of contamination may be deemed to be acceptable, e.g., the
purge fluid may be used to reduce but not completely eliminate
contamination. The introduction of more than one fluid into an
inlet may be controlled using any suitable technique; e.g., one or
more fluid sources may be able to be placed in fluid communication
with an inlet, where control of such fluid communication may be
controlled using one or more valves (e.g., needle valves or other
valves such as those discussed herein), which in some cases may be
controlled using a computer or other controller.
[0207] As a non-limiting example, FIG. 5 illustrates the use of a
nozzle or mixing chamber with only one input. In this figure,
nozzle 15 includes an outlet 18 and a single input 39. However, in
fluidic communication with input 39 are a plurality of different
sources of fluid 51, 52, 53, 54, and 55. (Five sources are provided
here by way of example only, but more or fewer sources may be used
in other embodiments.) In this figure, source 51 may be, for
example, a purge fluid, while sources 52, 53, 54, and 55 may be
sources of various fluids or reactants to be introduced into nozzle
15. As a non-limiting example, different combinations of reactants
may be introduced into the nozzle from the different sources of
fluid, while purge fluid from source 51 may be used to purge inlet
39 between different fluids, e.g., to reduce contamination.
[0208] FIG. 6 illustrates a system in which a purge fluid may be
withdrawn at various locations. In this figure, nozzle 15 includes
an inlet 31 in fluid communication with a source of purge fluid 51
and a sources of other fluids 52 and 53. (Two are shown here for
explanatory purposes, but more or fewer sources may be used in
other embodiments.) Also shown in this figure are outlets 63 and
65, in addition to outlet 18 of the nozzle. The flow of fluid may
be controlled by one or more valves or other apparatuses, e.g.,
controlled by a computer or other controller. Thus, in this
example, a purge fluid may be introduced from fluid source 51 and
controllably withdrawn using outlet 63 (i.e., without entering
nozzle 15), outlet 65 (i.e., passing through nozzle 15 but not
outlet 18), or outlet 18. Other purge configurations are also
possible in other embodiments.
[0209] In various aspects, a variety of foams or other products
(such as composites) may be produced. For example, in some
embodiments, a foam may be created from a foam precursor comprising
a polymer and a cross-linking agent. The polymer can comprise
polyol such as a low number average molecular weight diol, high
number-average molecular weight diol, a low number-average
molecular weight triol, a high number-average molecular weight
triol, or a high number-average molecular weight monol. For
instance, a high molecular weight monol, diol, or triol may have a
number-average molecular weight of greater than 300, 400, or 500,
while a low molecular weight monol, diol, or triol may have a
number-average molecular weight less than 300, 400, or 500. Other
examples of polymers include, but are not limited to, epoxies,
acrylates, cyanate esters, silicones, polyesters, phenolics,
hydrogels, or the like.
[0210] In one set of embodiments, the polymer includes a
polyurethane, e.g., formed by reacting the polyol with an
isocyanate. The polyol may be any suitable polyhydroxy compound.
For example, the polyol may be a hydroxy-terminated ester, ether or
carbonate diol, or a hydroxyl-terminated polybutadiene polymer.
Non-limiting examples of polyalkylene ether glycols include
polyethylene ether glycols, poly-1,2-propylene ether glycols,
polytetramethylene ether glycols, poly-1,2-dimethylethylene ether
glycols, poly-1,2-butylene ether glycol, and polydecamethylene
ether glycols. Examples of polyester polyols include polybutylene
adipate and polyethylene terephthalate. Examples of polycarbonate
diols include polytetramethylene carbonate diol, polypentamethylene
carbonate diol, polyhexamethylene carbonate diol,
polyhexane-1,6-carbonate diol and poly(1,6-hexyl-1,2-ethyl
carbonate)diol. However, many other suitable polyhydroxy compounds
can also be used depending upon the desired application. Any
suitable polyol, polythiol or polyamine or mixture thereof that is
suitable for this purpose may be used, such as, for example, mixed
diols comprising a 2,4-dialkyl-1,5-pentanediol and a
2,2-dialkyl-1,3-propanediol. Specific examples of
2,4-dialkyl-1,5-pentanediols include 2,4-dimethyl-1,5-pentanediol,
2-ethyl-4-methyl-1,5-pentanediol,
2-methyl-4-propyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol,
2-ethyl-4-propyl-1,5-pentanediol, 2,4-dipropyl-1,5-pentanediol,
2-isoptopyl-4-methyl-1,5-pentanediol,
2-ethyl-4-isoptopyl-1,5-pentanediol,
2,4-diisopropyl-1,5-pentanediol,
2-isopropyl-4-propyl-1,5-pentanediol, 2,4-dibutyl-1,5-pentanediol,
2,4-dipentyl-1,5-pentanediol, 2,4-dihexyl-1,5-pentanediol, and the
like. Specific examples of 2,2-dialkyl-1,3-propanediols include
2,2-dipentyl-1,3-propanediol, 2,2-dihexyl-1,3-propanediol and the
like.
[0211] In some cases, longer-chain or higher molecular weight
polyols may be used to produce relatively softer materials because
they have more polyol relative to isocyanate. In some cases, the
isocyanate can also be underindexed compared to the number of
reactive sites on the polyol to make a softer foam that behaves
less elastically.
[0212] The cross-linking agent, if present, can comprise an
isocyanate in some cases, and/or an isocyanate prepolymer. An
isocyanate may have more than one functional isocyanate group per
molecule and may be any suitable aromatic, aliphatic or
cycloaliphatic polyisocyanate. In some cases, the isocyanate is a
diisocyanate. One non-limiting example is an organic diisocyanate,
such as methylene diphenyl diisocyanate. Additional examples of
organic diisocyanates include 4,4'-diisocyanatodiphenylmethane,
2,4'-diisocyanatodiphenylmethane, isophorone diisocyanate,
p-phenylene diisocyanate, 2,6-toluene diisocyanate, polyphenyl
polymethylene polyisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane,
1,4-diisocyanatocyclohexane, 1,6-hexamethylene diisocyanate,
1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenyl
diisocyanate, 4,4'-diisocyanatodicyclohexylmethane,
2,4'-diisocyanatodicyclohexylmethane, and 2,4-toluene diisocyanate,
or combinations thereof. In some cases, an isocyanate prepolymer
may be used, e.g., in addition to and/or instead of an isocyanate.
For instance, where two isocyanates are added to the ends of a
polyol, so it still has functionality of two, but with a higher
molecular weight.
[0213] In addition, it should be understood that a cross-linking
agent is not required. For example, in some embodiments a polymer
(such as a thermoplastic polyurethane) can be mixed with fillers
and frothed in a nozzle or a mixing chamber, then cooled upon
exiting to form a foam.
[0214] In some embodiments, no foam is produced and a crosslinked
product results. As a non-limiting example, a high number-average
molecular weight diol may be mixed with an isocyanate (e.g., a
diisocyanate, or other isocyanates described herein) and deposited
onto a substrate, e.g., to produce a thermoplastic elastomer. In
another embodiment, a low number-average molecular weight diol can
be mixed with an isocyanate and deposited onto a substrate, e.g.,
to produce a rigid thermoplastic. In yet another embodiment, a high
number-average molecular weight diol and a high number-average
molecular weight triol can be mixed, and then the polyol mixture
mixed with an isocyanate and deposited onto a substrate, e.g., to
produce a flexible thermosetting elastomer with high
resiliency.
[0215] In some embodiments, the foam precursor comprises a
polyurethane, an epoxy, a silicone, a cyanoacrylate, an adhesive, a
cyanate ester, a polyester, a polyimide, a phenolic, or another
suitable material. In another embodiment, the foam precursor could
comprise a decomposeable binder and particles which stabilize the
bubble interface. In some cases, the particles may be sintered at
the bubble interface to form a non-polymeric foam, e.g., a metal
foam or a ceramic foam.
[0216] As a non-limiting example of a foam, in one embodiment, a
high number-average molecular weight diol and a high number-average
molecular weight triol are mixed with a surfactant, and then the
polyol-surfactant mixture is mixed with an isocyanate. The foam
precursor that results may be mixed with nitrogen, or another gas,
and deposited onto a substrate. Mixing techniques such as those
discussed herein, e.g., involving more than one stage of mixing or
combining fluids, may be used.
[0217] As yet another non-limiting example, a high number-average
molecular weight diol and a high number-average molecular weight
monol are mixed with a surfactant, and then the polyol-surfactant
mixture is mixed with an isocyanate. Mixing techniques such as
those discussed herein, e.g., involving more than one stage of
mixing or combining fluids, may be used. The foam precursor that
results is then mixed with nitrogen, or another gas, and deposited
onto a substrate. This may be used to produce memory foam, or other
types of foam.
[0218] As mentioned, in some embodiments, a surfactant may be used
to produce a foam or other product as discussed herein. For
example, a surfactant may be used to facilitate the introduction of
gas into a fluid, the subsequent stability of the bubbles that are
formed, and/or the rheology of the foam can be altered or tuned
using various surfactants, or altering their concentration, etc.
For instance, in one embodiment, a surfactant may be used that
comprises a first moiety with affinity for an air-liquid interface,
e.g., to facilitate the introduction of gas into a fluid.
Non-limiting examples of such surfactants include sodium stearate,
sodium dodecyl sulfate, or silicone-based surfactants such as
silicone polyethers. Many such surfactants are widely available
commercially.
[0219] In some cases, a surfactant molecule may be used that allows
production of a high yield stress foam, e.g., a foam able to
maintain its shape after deposition on a substrate. For example, in
some embodiments, a high-yield stress inducing surfactant is one
where the end of the surfactant is more soluble in the continuous
phase of the foam precursor. The surfactant may have a relatively
high molecular weight, and may be non-ionic. Non-limiting examples
of such surfactants include surfactants with a molecular weight of
greater than or equal to 1500 Daltons. In addition, in some cases,
a surfactant molecule may be used that allows production of a low
yield stress foam, e.g., a foam unable to maintain its shape after
deposition on a substrate, and the foam may conform to the material
around it after deposition. In some embodiments, a low-yield stress
inducing surfactant is one where the soluble end may be either
charged or have a relatively low molecular weight, e.g., such that
no entanglement between the surfactants is able to occur.
Non-limiting examples of such surfactants include surfactants with
a low molecular weight (e.g., silicone surfactants with a low
molecular weight). In addition, in some embodiments, different
types of surfactants may be used, e.g., a high yield and a low
yield surfactant. By varying the relative concentration of the
first surfactant and the second surfactant in the mixture, the
resultant foam may vary from high yield stress to low or no yield
stress, depending upon the application.
[0220] In certain embodiments, the first surfactant molecule may
comprise a first moiety having an affinity for an air-liquid
interface, and a second moiety that comprises a long chain that is
soluble in the foam precursor and prone to entanglement. The second
surfactant molecule may, in some instances, comprise the same first
moiety with affinity for the air-liquid interface, and a second
moiety that comprises a short chain with an electrostatic charge.
The electrostatic charge may in some cases be such that the cells
of the closed-cell foam repel one another and can move freely past
one another.
[0221] The cell-forming agent, in some embodiments, forms cells
within a material such as a foam or froth, as discussed herein. For
instance, the cell-forming agent may comprise water, and/or a
gaseous material such as air, carbon dioxide, nitrogen, butane, or
the like. In some embodiments, the cell-forming agent comprises a
blowing agent that is added that can generate a gas, e.g.,
chemically. The microfluidic printing nozzle may disperse the
blowing agent in a material, for example a polymer, to form a
two-phase mixture of blowing agent cells within the polymer. Thus,
the blowing agent can comprise a material that decomposes into a
gas, e.g., at an elevated temperature. In some cases, the blowing
agent can comprise a gaseous material that maintains its liquid
state by cooling or pressurization, and reverts to its native gas
state when the pressure is released or the blowing agent is heated,
which may cause the blowing agent to form a gas, e.g., to cause
cells in the polymer to grow. The resultant gas may become trapped
in cells within the material, e.g., forming a foam.
[0222] As an example of use of a blowing agent, the microfluidic
printing nozzle may mix a blowing agent with a material, for
example a polymer, which may undergo a chemical reaction to cause
the formation of a gas. Chemical blowing agents may include
generally low molecular weight organic compounds that decompose to
release a gas such as nitrogen, carbon dioxide, or carbon monoxide.
Non-limiting examples of chemical blowing agents include azo
compounds such as azodicarbonamide.
[0223] Thus, in some cases, the blowing agent can be used to create
foams that form cells by induction by heat, removal of pressure, or
the like. For instance, a foam precursor can be mixed with the
blowing agent and deposited onto a substrate or part without
forming cells until after deposition, or with only partially formed
cells. Thus, in some cases, material may be deposited onto a
substrate, then induced to form cells by heating the material.
After deposition, cells may form within the product, e.g., by
induction by heat, removal of pressure, or the like.
[0224] As a non-limiting example, a foam may comprise an
ethylene-vinyl acetate foam, which may be utilized in footwear or
other applications. A blowing agent may be selected such that the
agent phase-transitions into a gas at a temperature at which the
polymer containing it is soft and malleable. In some cases, the
polymer can expand (e.g., expand up to 600%) as the cells form
without rupturing, and the resultant material can be cooled to form
a solid foam.
[0225] As another example, water may be used in another embodiment
as a cell-forming agent. For example, a water-blown foam may be
produced where water and a surfactant are mixed into a polymer
component, which is then mixed with isocyanate or another substance
able to react with water, e.g., to produce a gas. For instance, as
a non-limiting example, isocyanate chemically reacts with both
water and polyol; the reaction of polyols with isocyanate may be
used to increase the molecular weight of the polymer, e.g., to form
a polyurethane, while the reaction of water with the isocyanate
forms carbon dioxide gas. The carbon dioxide gas becomes trapped in
the polymer as it solidifies, and a foam is thus created. In some
cases, the amount of water may be controlled to control the
properties of the resulting foam, such as density or cell size,
e.g., during the reaction process.
[0226] As yet another non-limiting example, a blowing agent that
decomposes very slowly with time may be selected, such that a foam
may be very slowly inflated without any heating required. In some
cases, this may result in a foam with improved in rebound
properties (e.g., compression strength) versus a substantially
similar foam where heat was applied to activate the blowing agent,
resulting in a higher performing article for use in footwear.
[0227] In addition, in some embodiments, a material may be
deposited onto a substrate, e.g., to fill a mold, then the mold may
be sealed and the blowing agent induced to form a foam, which may
then start to fill in the mold as the foam expands.
[0228] In some embodiments, additives are introduced into the
mixture. They may be introduced at any suitable point, for example,
directly into a nozzle or mixing chamber (e.g., through one or more
separate inlets), or upstream of the nozzle or mixing chamber
(e.g., using a series of mixing chambers, as described herein). In
some embodiments, an additive may be added directly to another
fluid (e.g., without necessarily requiring a mixing chamber). These
additives can comprise particles such as reinforcing particles
(e.g., as described herein), hollow glass spheres, hollow elastomer
spheres (e.g., hollow polyurethane spheres), a pigment, a metal, a
filler such as a thermally conductive filler, a filler having a
relative dielectric constant of at least 5, an ultraviolet
stabilizer, a filler concentrate, or another suitable additive.
Additional examples of additives include surfactants (e.g.,
silicone surfactants), catalysts, nucleation promotors, fillers for
better abrasion resistance, chemical foaming agents, etc.
Combinations of these and/or other additives are also possible. As
a non-limiting example, a 3D printed closed-cell foam may be
produced that incorporates particulate additives comprising a
cellular network of cell walls separating empty cells, where the
cell walls comprise a polymer composite including filler particles
dispersed in a polymer matrix.
[0229] As a non-limiting example, hollow glass spheres or hollow
elastomer spheres (e.g., hollow polyurethane spheres) may be
incorporated into polyurethanes or other polymers as discussed
herein to reduce density, increase stiffness, reduce dielectric
constant, provide more nucleation sites for bubble formation, or
the like. For instance, hollow spheres may be used to decrease
weight. Hollow spheres, for example hollow glass spheres or hollow
polymer spheres can be varied, e.g., spatially, in order to change
the properties of the product. Other examples of particles (e.g.,
reinforcing particles) that can be used, e.g., in addition to
and/or instead of hollow glass spheres include, but are not limited
to, rubber particles and other particles described herein.
[0230] In one aspect, a foam may be printed (e.g., via 3D-printing)
into a structure defining a plurality of cells, i.e., into a
foam-like structure. Thus, a foam may be printed as part of a
larger foam-like structure, e.g., where the walls of the foam-like
structure (e.g., defining cells of the foam-like structure
themselves) are foams having cells. The foam-like structure may
have open cells, closed cells, or any combination of open and
closed cells, independently of the structure of the foam itself
forming the foam-like structure.
[0231] In one set of embodiments, one or more methods for
manufacturing 3D-printed articles as described herein may be
advantageous in comparison to other methods for making articles for
use in footwear. For example, a footwear manufacturer employing a
method as described herein may be able to use fewer processes to
create the article than would be employed in other comparable
processes (e.g., the manufacturer may use a three-dimensional
printer (3D printer) in a single process to make a component that
would otherwise be made by a combination of several processes such
as injection molding, lamination, and the like). This may allow for
more rapid and/or more facile manufacturing. As another example,
one or more of the methods described herein may not necessarily
require the use equipment that is expensive to manufacture and
whose cost is typically recovered only after repeated use (e.g.,
molds). Some of the methods described herein may instead employ a
3D printer to create articles whose design can be modified as
desired with little or no added cost. In some embodiments, it may
be economical for methods as described herein to create small
batches of 3D-printed articles (e.g., batches of less than 100,
less than 50, or less than 10). It is thus possible for
manufacturers may employ some of the methods described herein to
respond to changing market conditions, to create articles for use
in footwear that are designed for individual users or groups of
users, etc. In some embodiments, it may be advantageous to use one
or more of the methods described herein to fabricate a 3D-printed
article at the point of sale and/or to avoid long distance
shipping. Other examples may be seen in U.S. Pat. Apl. Ser. No.
62/464,364, entitled "Systems and Methods for Three-Dimensional
Printing of Footwear and Other Articles," filed Feb. 27, 2017,
incorporated herein by reference in its entirety.
[0232] A non-limiting example of a 3D-printed article for use in
footwear is shown in FIG. 14A. In this figure, 3D-printed article
100 comprises first portion 110 and second portion 120. As used
herein, a portion of an article may refer to any collection of
points within the article (i.e., points that are within the portion
of space bounded by the external surfaces of the article). Portions
of the article are typically, but not always, volumes of space
within the article (in some embodiments, a portion may be a surface
within an article, a line within an article, or a point within an
article). Portions of the article may be continuous (i.e., each
point within the portion may be connected by a pathway that does
not pass through any points external to the portion) or may be
discontinuous (i.e., the portion may comprise at least one point
that cannot be connected to at least one other point within the
article by a pathway that does not pass through any points external
to the portion). Portions of an article may be substantially
homogeneous with respect to one or more properties (e.g., one or
more properties of the portion may vary with a standard deviation
of less than or equal to 1%, 2%, 5%, or 10% throughout the
portion), and/or may be heterogeneous with respect to one or more
properties (e.g., one or more properties of the portion may vary
with a standard deviation of greater than or equal to 1%, 2%, 5%,
or 10% throughout the portion).
[0233] In some embodiments, a 3D-printed article may comprise two
or more portions, where one or more properties (e.g., average pore
size, density, stiffness, stiffness of solid components of the
article, Shore A hardness, degree of cross-linking, chemical
composition, color, abrasion resistance, thermal conductivity,
electrical conductivity, stiffness anisotropy, elastic modulus,
flexural modulus, filler content, opacity, conductivity,
breathability) of a first portion may differ from one or more
properties of a second portion. In some embodiments, the difference
in properties between the first portion and the second portion may
comprise a gradient of the one or more properties (e.g., the
property or properties may vary relatively smoothly from a first
value in the first portion to a second value in the second
portion). In other embodiments, there may be a sharp change in one
or more of the properties at a boundary of one or more of the first
portion and the second portion. Other examples include, but are not
limited to, average largest dimension of particles (e.g.,
reinforcing particles), average concentration of particles (e.g.,
reinforcing particles), surface roughness, compression strength,
slip resistance, or abrasion resistance.
[0234] It should be understood that while FIG. 14A shows the second
portion positioned above the first portion, other arrangements of
the first portion with respect to the second portion are also
contemplated. For example, the first portion may be positioned
beside the second portion, the first portion may surround the
second portion, the first portion and the second portion may
interpenetrate (e.g., a first portion may comprise a foam that
interpenetrates with a second portion that comprises an elastomer),
etc. It should also be noted that while FIG. 14A shows the second
portion directly adjacent the first portion, this configuration
should not be understood to be limiting. In some embodiments, the
first portion may be separated from the second portion by one or
more intervening portions positioned between the first portion and
the second portion. As used herein, a portion that is positioned
"between" two portions may be directly between the two portions
such that no intervening portion is present, or an intervening
portion may be present.
[0235] Similarly, while FIG. 14A only depicts two portions, it
should also be understood that an article may comprise three
portions, four portions, or more portions. In some embodiments,
portions within a 3D-printed article as described herein may also
further comprise sub-portions. Each portion and/or sub-portion may
differ from each other (sub-)portion in at least one way (e.g., any
two (sub-)portions may comprise at least one property that is
different), or one or more (sub-)portions may be substantially
similar to other (sub-)portion(s) of the 3D-printed article. In
some embodiments, a first portion and a second portion as described
herein may be components of a 3D-printed article that is a single
integrated material. As used herein, two or more portions that
together form a single integrated material are not separated by a
separable interface. In some embodiments, a single integrated
material may not separate into discrete parts during the course of
normal use, and/or may be separated into discrete parts whose
morphologies would not be predictable prior to normal use and/or
along interfaces that would not be predictable prior to normal use.
For instance, a single integrated material may lack seams, lack an
adhesive that bonds two or more portions together, and/or lack an
interface at which one or more properties (e.g., average pore size,
density, stiffness, stiffness of solid components of the article,
Shore A hardness, degree of cross-linking, chemical composition,
color, abrasion resistance, thermal conductivity, electrical
conductivity, stiffness anisotropy, elastic modulus, flexural
modulus, filler content, opacity, conductivity, breathability)
undergo step changes.
[0236] In some embodiments, one or more portions may together form
an 3D-printed article with one or more of the following features:
macrovoids embedded within the article (e.g., a midsole) without an
intersecting interface from overmolding, lamination, or ultrasonic
welding; one or more open cell lattices; variations in density
across geometries that would be challenging to form by molding;
interpenetrating foams and elastomers that may, in some
embodiments, not be separated by an interface due to molding or
lamination; and/or one or more interfaces between different
materials with extreme undercuts (e.g., materials with a negative
draft angle, materials which cannot be injection molded using a
single mold because they would be unable to slide out of the
mold).
[0237] In some embodiments, a 3D-printed article (e.g., a
3D-printed article comprising two or more portions) may be a foam
(e.g., a closed cell foam). For instance, FIG. 14B shows one
non-limiting embodiment of a 3D-printed article 100 which is a foam
comprising pores 130. The foam may be a material comprising a
matrix and pores disposed within the matrix. Pores may be randomly
distributed throughout the foam, or may be positioned at regular
and/or pre-determined intervals. The material present within the
pores of a foam is typically of a different phase than the material
forming the matrix of the foam (e.g., a foam may comprise pores
that comprise gas within a matrix that comprises a liquid and/or a
solid). As would be understood to one of ordinary skill in the art,
in a closed-cell foam, the cells of the foam are typically isolated
or separated from each other. By contrast, in an open-cell foam,
the cells of the foam are interconnected with each other; for
example, they may be formed in an interconnected fashion, or the
cells may be ruptured or become interconnected during or after
formation of the foam. These conditions are typically more violent
foaming conditions than those resulting in a closed-cell foam. The
foam may be formed from a variety of polymers and gases. The gases
may be introduced into the foam during formation (e.g.,
physically), and/or generated during formation (e.g., via chemical
reaction). In addition, in some cases, a gas may be introduced by
providing a liquid that forms a gas, e.g., upon a decrease in
pressure or an increase in temperature. For instance, a liquid such
as butane may be kept under pressure and/or cooled prior to
introduction into the nozzle or the mixing chamber; a change in
temperature and/or pressure may cause the liquid to form a gas.
Without wishing to be bound by theory, closed cell foams and open
cell foams may have different properties (e.g., closed cell foams
may have different values of density, stiffness, Shore A hardness,
and the like than otherwise equivalent open cell foams) and may be
suitable for different applications. In some embodiments, closed
cell foams may have properties that are better suited to footwear
applications than open cell foams. In some embodiments, a
3D-printed article or a portion thereof may comprise an enclosed
open cell foam, or an open cell foam surrounded by a layer of
continuous material. In some cases, an enclosed open cell foam may
be suitable for use as an air cushion, and/or may have tactile
properties that may be varied by varying infill density.
[0238] It should also be understood that certain 3D-printed
articles described herein may not be foams (i.e., they may not
include any pores). For instance, certain embodiments may relate to
3D-printed articles that are not foams and that comprise one or
more elastomers. In addition, in some cases, an article may be
printed that can then be formed into a foam, e.g., using a chemical
reaction to produce a gas within the article.
[0239] As shown in FIG. 14C, in some but not necessarily all
embodiments, a 3D-printed article that is a foam (e.g., a
closed-cell foam that is optionally a single integrated material)
may comprise one or more portions having different properties. FIG.
14C shows 3D-printed article 100 comprising first portion 110,
second portion 120, and pores 130. Although FIG. 14C depicts a
3D-printed article comprising an average pore (or cell) size in the
first portion (i.e. a first average pore size) that is different
from an average pore (or cell) size in the second portion (i.e., a
second average pore size), in some embodiments the first portion
and the second portion may have the same average pore size but may
comprise differences in other properties (e.g., one or more of the
density, stiffness, Shore A hardness, degree of cross-linking,
chemical composition may be different in the first portion than in
the second portion). Thus the pore sizes are presented here for
illustrative portions only. Similarly, although FIG. 14C shows an
average pore size in the first portion that is larger than the
average pore size in the second portion, in some embodiments the
average pore size of the first portion may be smaller than the
average pore size of the second portion.
[0240] In some embodiments, a 3D-printed article as designed herein
may be suitable for use as a component of one or more articles of
footwear. FIG. 15 shows one non-limiting embodiment of an article
of footwear 1000. The article of footwear comprises a sole, a toe
box, an upper; lacing, a heel counter, and a pull tab. It should be
understood that 3D-printed articles suitable for use in footwear
may form any of the components or be a portion of any or all of the
components shown in FIG. 15. In some embodiments, multiple
3D-printed articles may be positioned on a single article of
footwear (e.g., a single article of footwear may comprise a
3D-printed article that is disposed on a sole or is a sole and a
3D-printed article that is disposed on an upper). In some
embodiments, the 3D-printed article may be a sole or a sole
component, such as an outsole, a midsole, or an insole. In some
embodiments, the 3D-printed article may be an article that is
printed onto a sole component, such as a midsole and/or insole that
is printed onto an outsole (e.g., a commercially available outsole,
an outsole produced by a non-3D printing process). In some
embodiments, the 3D-printed article may be an article that is
printed onto an upper, such as a toe box, a heel counter, an ankle
support, and/or a pull tab. The upper may be one component of a
fully assembled shoe which lacks the part(s) to be printed, or it
may be an upper that has not been assembled with other footwear
components. In some embodiments, a 3D-printed article may be a
combination of two or more footwear components that are typically
provided as separate articles. For example, the 3D-printed article
may be able to serve as both a midsole and an insole, or may
comprise a midsole and an insole that are a single integrated
material. As another example, the 3D-printed article may be able to
serve as both an outsole and an insole, or may comprise an outsole
and an insole that are a single integrated material. In some
embodiments, a 3D-printed article comprising two or more footwear
components (e.g., a 3D-printed article comprising a midsole and an
insole, a 3D-printed article comprising an outsole and an insole)
may be printed using a single integrated process. Although FIG. 15
shows an athletic shoe, 3D-printed articles suitable for use in
other types of footwear are also contemplated as described in
further detail below. In some embodiments, the 3D-printed article
may also or instead be suitable for one or more non-footwear
components, such as orthotics and/or prosthetics.
[0241] As described above, certain articles as described herein may
be formed by a process involving one or more 3D-printing steps. In
some embodiments, an article may be formed by a process involving
both one or more 3D-printing steps and one or more non-3D-printing
steps. For example, an article may be formed by a first 3D-printing
step followed by a first non-3D-printing step which is optionally
followed by one or more further 3D-printing steps or
non-3D-printing steps. For example, a sole or sole component may be
3D-printed into a mold to form a first portion and then a material
may be injection molded or compression molded above the first
portion to form the second portion. Third, fourth, fifth, and/or
higher numbered portions may then optionally be formed on the
second portion (by, e.g., 3D-printing). As another example, a
non-3D printing step may comprise directly bonding two materials by
pressing a first material (e.g., a non-3D-printed material, an
upper) into a second 3D-printed material (e.g., a 3D-printed
midsole) prior to full curing of the second material. As a third
example, an inkjet finishing process may be applied to deposit one
or more materials (e.g., one more pigments) on a 3D-printed article
or on a material disposed on a 3D-printed article (e.g., a material
injection molded or compression molded on a 3D-printed article). In
some embodiments, an inkjet finishing process may enhance the
surface quality of the article that is subject to it.
[0242] In some cases, 3D-printed foams (e.g., closed-cell foams,
open-cell foams, etc.) may be prepared as discussed herein using
various inputs, as described herein. For instance, the foam density
may be varied by varying the amount of added gas, the amount of
added water (e.g., in water-blown foam applications), the amount of
added chemical blowing agent, etc. As another example, the foam
density constant may be held constant, but the cross-link density
or isocyanate content may be varied to change properties such as
the elasticity, elongation, or stiffness of the foam.
[0243] In some embodiments, one or more properties of a mixture
that is 3D-printed from a nozzle may change as a function of time
and/or nozzle position with respect to the substrate. For instance,
the composition of one or more components and/or the wt % of one or
more components within the mixture may change as a function of
time. In some embodiments, one or more physical parameters of the
nozzle and/or the substrate may change as a function of time. As an
example, the temperature of the nozzle and/or the substrate may
change as a function of time. Without wishing to be bound by
theory, the temperature of the nozzle and the temperature of the
substrate may affect the types of reactions that occur between
various components (e.g., cross-linking reactions, foaming
reactions, reactions within the nozzle, reactions on the substrate)
and/or the rates at which these reactions occur. This may in turn
affect the chemical structure of the mixture (e.g., the composition
of the mixture, the degree of cross-linking of the resultant foam)
during and/or after printing, and/or affect one or more physical
properties of the mixture (e.g., the viscosity of the mixture, the
average pore size of the resultant foam, the density of the
resultant foam, the stiffness of the resultant foam, the Shore A
hardness of the resultant foam) during and/or after printing. In
some embodiments, changes in substrate or nozzle temperature during
printing may allow for different portions of the 3D-printed article
(e.g., those printed at different times and/or in different
positions on the substrate) to have different chemical or physical
properties. In some embodiments, the portions with different
chemical and/or physical properties may be printed in a single
continuous process, and/or may together form a single integrated
material.
[0244] In some cases, as discussed herein, a foam precursor, prior
to curing, may have different rheological properties than the
starting raw materials without gas content. For example, a mixture
of low viscosity fluids, gases, and/or surfactants, etc. having
Newtonian flow behavior before foaming can be used to produce a
precursor having non-Newtonian flow characteristics, e.g., with a
yield stress, or shear-thickening or shear-thinning behavior. This
may be used herein to produce a precursor having a rheological
profile suitable for printing, e.g., on a substrate. Fluids such as
incompressible Newtonian fluids or gases can be controlled
introduced into a nozzle (e.g., prior to mixing) and precisely
metered onto a substrate during deposition. In some cases, the
foaming process may start within the nozzle, and controlled to
control deposition of the precursor and/or the final mechanical
properties of the foam.
[0245] U.S. Pat. Apl. Ser. Nos. 62/464,363 and 62/464,364 are each
incorporated herein by reference in its entirety.
[0246] The following examples are intended to illustrate certain
embodiments of the present invention, but do not exemplify the full
scope of the invention.
Example 1
[0247] Water-blown polyurethane foam. A mixing nozzle was
configured to have two inputs: Input A for an isocyanate
pre-polymer, and Input B for a mixture of polyols, surfactants, and
water. When the two inputs were combined in the mixing chamber, the
water and polyols reacted with the isocyanate to form a
polyurethane matrix with a higher number-average molecular weight
than the polyols and carbon dioxide that became trapped in the
polyurethane matrix to form a foam. Inputs A and B were as
follows:
Input A: (one or more of the following components flowed into the
mixing nozzle)
TABLE-US-00001 Amount Component Description (g) Polytech 20-A
Isocyanate prepolymer 150 BJB enterprises f-115-a Isocyanate
prepolymer 150 Polytech F-3 - A Isocyanate prepolymer 110 Polyfiber
II Polyethylene fiber 40 (rheological modifier)
Input B: (one or more of the following components flowed into the
mixing nozzle, in addition to water)
TABLE-US-00002 Amount Component Description (g) Polytech 20-B
Polyol blend for elastomer 150 BJB enterprises F-115-B Polyol blend
for soft elastomer 150 Polytech F-3-B Polyol, water, surfactant
blend 220 for foam promotion 3M S32 glass bubbles Foam stabilizer
and bubble 42 nucleation site Polyfiber II Polyethylene fiber
(rheological 40 modifier) Polytech White White Pigment 16 Poly UV
UV stabilizer 3.38 Evonik Tegostab B 8952 Silicone surfactant for
foam 10 stabilizing Polytek 74/75 part X Organometallic catalyst
15.2 accelerator
Such a water-blown polyurethane foam (white, top portion) was
co-printed with a non-foaming two-part polyurethane elastomer
(blue, bottom portion) to form a shoe sole, as is shown in FIG.
7.
[0248] A mean pore size of the foam was characterized by slicing
through a 3D-printed filament to obtain a cross-section of the foam
and then imaging the cross-section with a light microscope and
using image analysis (depicted in FIG. 8 with circles and
measurements in microns).
Example 2
[0249] Silicone gradient material. A coupon with a gradient in both
stiffness and color was fabricated using a two-input mixing nozzle
system, as shown in FIG. 9. The clear-colored silicone (left) was a
soft elastomer with a Shore hardness of 10 A. The blue colored
silicone (right) was a medium hard elastomer with a Shore hardness
of 70 A. In this example, parts A and B were mixed together to make
a precursor to the soft elastomer (Input 1), and parts A' and B'
were mixed together to make a precursor to the hard elastomer
(Input 2) prior to injecting into the mixing chamber. The coupon
was printed with each layer as a single meandering print path where
the beginning of the print path (left-most position in FIG. 9) was
100% A and B (e.g. 100% Input 1), and the end of the print path
(right-most position in FIG. 9) was 100% A' and B' (e.g. 100% Input
2). The volume ratio of Input 1 to Input 2 was varied continuously
from one side of the 3D-printed coupon to the other.
[0250] The inputs were as follows:
Input 1, A and B: (two or more of the following components flowed
into the mixing nozzle)
TABLE-US-00003 Amount Component Description (g) Blue star LSR 4301
A Part A soft platinum cure silicone 74 elastomer Blue star LSR
4301 B Part B soft platinum cure silicone 74 elastomer Aerosil 300
Fumed silica (rheological modifier) 8.9
Input 2, A' and B': (two or more of the following components flowed
into the mixing nozzle)
TABLE-US-00004 Amount Component Description (g) Quantumn Silicones
229 LV-A Part A' 60A platinum cure 25.5 silicone gel Quantumn
Silicones 229 LV-B Part B' 60A platinum cure 25.5 silicone gel Blue
Star LSR 4350 A Part A' 50A platinum cure 8.5 silicone elastomer
Blue Star LSR 4350 B Part B' 50A platinum cure 8.5 silicone
elastomer Blue Star LSR 4301 A Part A' 1A platinum cure 10.5
silicone elastomer Blue Star LSR 4301 B Part B' 1A platinum cure
10.5 silicone elastomer Smooth-on Silc-Pig Blue Blue pigment 0.03
Aerosil 300 Fumed Silica (Rheological 6.775 modifier)
Example 3
[0251] Mixing cells into a hydrogel. A hydrogel structure is formed
using the mixing system. A first input to the mixing nozzle
comprises a cross-linking agent for the hydrogel, and a second
input to the mixing nozzle comprises an uncross-linked hydrogel
precursor. Additional inputs into the mixing nozzle include
concentrated cell suspensions of various types, different types of
cell media, and concentrates of cell growth factors and chemical
signaling agents.
Example 4
[0252] Printing a rigid epoxy foam. A mixing nozzle comprises a
mixing/frothing chamber and at least three inputs. A first input is
a gas such as nitrogen or air. A second input is a
bisphenol-A-based resin such as Epon.RTM. Resin 828, with an added
surfactant that stabilizes bubbles. A third input is a curing agent
for epoxy resin such as a diamine like ethylenediamine. The second
and third input are added to the mixing chamber to induce the epoxy
resin to cross-link into a solid thermoset. The gas input flowrate
can be varied along with the impeller speed to create a rigid
thermosetting foam with variable dielectric properties due to air
content.
Example 5
[0253] Mixing therapeutics into a biodegradable matrix material. A
multi-input system can be used for creating a
therapeutic-impregnated matrix of material such as a pill. Inputs
include: a solution of a biodegradable polymer with a high
degradation rate; a solution of a biodegradable polymer with a low
degradation rate; a solution of a first active therapeutic agent; a
solution of a second active therapeutic agent; a sugar or flow
inducing agent; or another suitable input.
[0254] A pill-like architecture can then be 3D-printed, wherein the
composition of the pill can be varied spatially. For example, the
external part of the pill could be 3D-printed to contain a first
therapeutic agent, and the material printed has a fast degradation
profile for a quick release of the first therapeutic agent. Then
the internal part of the pill may be printed with a material that
degrades slowly, and may contain two different types of therapeutic
agents. The external surface of the pill may have a printed inert
sugar coating so that no therapeutic release occurs until the pill
has passed through the esophagus. This allows the possibility of
combining many pills into one. By this process, a 3D-printed pill
can have a customized therapeutic release profile that is specific
to a patient.
[0255] The same methodology to 3D-print pills can be applied to
3D-printed implantable long-term therapeutic release depots. For
example, this 3D-printing methodology can be applied towards
fabricating a skin tissue graft, wherein drugs, growth factors,
antibiotics, and cells can be printed with variable spatial
concentration to promote the regrowth of a skin defect such as a
severe burn. Printing an implantable therapeutic depot may involve
an input that induces polymerization or cross-linking.
Example 6
[0256] Printing a rigid epoxy foam: printing a stimuli-responsive
structure from a reactive polyurethane system. A system comprising
at least four inputs may be used to 3D-print a stimuli-responsive
structure, the inputs comprising: an isocyanate cross-linking
agent; a polyol mixture wherein the components have low stiffness;
a polyol mixture wherein the components have high stiffness; and a
chemical blowing agent concentrate dissolved in polyol.
[0257] For example, a tri-layer architecture can be 3D-printed to
accomplish the stimuli-responsive property. As shown in FIG. 10,
the top layer (1) forms a low-stiffness/high-flexibility elastomer
from inputs comprising a low-stiffness polyol mixture and an
isocyanate. The middle layer (2) in FIG. 10 forms a high-stiffness
elastomer from inputs comprising a high stiffness polyol mixture
and an isocyanate. Layer (2) functions as a strain-limiting layer.
The bottom layer (3) in FIG. 10 initially forms an elastomer with
similar properties to the top layer after printing and partial
curing, and is formed from inputs comprising a high flexibility
polyol mixture, an isocyanate, and a chemical blowing agent. After
the entire structure is printed and partially cured, the structure
can be heated above the decomposition temperature of the chemical
blowing agent. This causes the bottom layer (3) to expand into a
foam. However, since layer (3) is chemically and physically bonded
to the middle strain-limiting layer (2) that has higher stiffness,
the bottom layer (3) will generally expand, but will expand to a
lesser extent at the interface of the strain-limiting material.
This differential strain will cause the entire structure to curl.
Thus, FIG. 10 illustrates a 3D-printed stimuli-responsive tri-layer
polyurethane system, where heating results in curling of the
tri-layer structure (Example 6)
[0258] The expansion of the bottom material upon decomposition of
the chemical blowing agent, coupled with the strong interface with
the strain-limiting layer, causes a physical curling of the whole
tri-layer structure. Selective placement of the expandable material
containing the blowing agent can be utilized to programmatically
define deformations in printed parts that will not occur until
after the part is printed and heated.
Example 7
[0259] This example illustrates the formulation and printing of an
outsole material. First, a polyol concentrate was made by mixing
the ingredients at the prescribed ratio (Part B Fluid) using a
planetary centrifugal mixer. Next, the fillers (Outsole
Formulation, Part B) were added to the polyol concentrate and mixed
with a planetary centrifugal mixer under vacuum. Finally, the Part
B mixture was loaded into a syringe, and used to feed into one side
of the active mixing head. The same protocol was done for Part A in
a separate container.
Part B Fluid: Polyol concentrate:
TABLE-US-00005 Amount Component (g) 1,4-Butane diol 13 (13 wt %)
Carpol PGP-2012 -> polyether diol with ethylene oxide 40 (40 wt
%) cap 2000 Molecular weight Hydroxyl number 56 Carpol GP-725 ->
Polyether triol with ethylene oxide 25 (25 wt %) cap 700 Molecular
weight Hydroxyl number 240 Carpol GP-6015 -> polyether triol
with ethylene oxide 22 (22 wt %) cap 6000 molecular weight Hydroxyl
number 28 molecular sieve/microdessicant 5 (5 parts per hundred
resin) bismuth based organometallic complex (K-KAT XK-618) 1
Part A Fluid: Isocyanate prepolymer: BASF Lupranate 5030--polyester
and MDI quasi prepolymer with NCO content of 18.9%
Outsole Formulation:
TABLE-US-00006 [0260] Amount Component Description (g) isocyanate
prepolymer Part A 15 fumed silica Part A; filler 0.6 polyol
concentrate Part B 15 fumed silica Part B; filler, 0.45 with PDMS
coating ground tire rubber Part B; filler, with particles 10 size
180 microns chopped glass fiber Part B; filler; 1/32 inches long 3
with amino silane coating silicone oil Part B; filler; with
viscosity of 0.45 60,000 cP
[0261] While several embodiments of the present invention have been
described and illustrated herein, those of ordinary skill in the
art will readily envision a variety of other means and/or
structures for performing the functions and/or obtaining the
results and/or one or more of the advantages described herein, and
each of such variations and/or modifications is deemed to be within
the scope of the present invention. More generally, those skilled
in the art will readily appreciate that all parameters, dimensions,
materials, and configurations described herein are meant to be
exemplary and that the actual parameters, dimensions, materials,
and/or configurations will depend upon the specific application or
applications for which the teachings of the present invention
is/are used. Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many
equivalents to the specific embodiments of the invention described
herein. It is, therefore, to be understood that the foregoing
embodiments are presented by way of example only and that, within
the scope of the appended claims and equivalents thereto, the
invention may be practiced otherwise than as specifically described
and claimed. The present invention is directed to each individual
feature, system, article, material, kit, and/or method described
herein. In addition, any combination of two or more such features,
systems, articles, materials, kits, and/or methods, if such
features, systems, articles, materials, kits, and/or methods are
not mutually inconsistent, is included within the scope of the
present invention.
[0262] In cases where the present specification and a document
incorporated by reference include conflicting and/or inconsistent
disclosure, the present specification shall control. If two or more
documents incorporated by reference include conflicting and/or
inconsistent disclosure with respect to each other, then the
document having the later effective date shall control.
[0263] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms.
[0264] The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."
[0265] The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
Multiple elements listed with "and/or" should be construed in the
same fashion, i.e., "one or more" of the elements so conjoined.
Other elements may optionally be present other than the elements
specifically identified by the "and/or" clause, whether related or
unrelated to those elements specifically identified. Thus, as a
non-limiting example, a reference to "A and/or B", when used in
conjunction with open-ended language such as "comprising" can
refer, in one embodiment, to A only (optionally including elements
other than B); in another embodiment, to B only (optionally
including elements other than A); in yet another embodiment, to
both A and B (optionally including other elements); etc.
[0266] As used herein in the specification and in the claims, "or"
should be understood to have the same meaning as "and/or" as
defined above. For example, when separating items in a list, "or"
or "and/or" shall be interpreted as being inclusive, i.e., the
inclusion of at least one, but also including more than one, of a
number or list of elements, and, optionally, additional unlisted
items. Only terms clearly indicated to the contrary, such as "only
one of" or "exactly one of," or, when used in the claims,
"consisting of," will refer to the inclusion of exactly one element
of a number or list of elements. In general, the term "or" as used
herein shall only be interpreted as indicating exclusive
alternatives (i.e. "one or the other but not both") when preceded
by terms of exclusivity, such as "either," "one of," "only one of,"
or "exactly one of."
[0267] As used herein in the specification and in the claims, the
phrase "at least one," in reference to a list of one or more
elements, should be understood to mean at least one element
selected from any one or more of the elements in the list of
elements, but not necessarily including at least one of each and
every element specifically listed within the list of elements and
not excluding any combinations of elements in the list of elements.
This definition also allows that elements may optionally be present
other than the elements specifically identified within the list of
elements to which the phrase "at least one" refers, whether related
or unrelated to those elements specifically identified. Thus, as a
non-limiting example, "at least one of A and B" (or, equivalently,
"at least one of A or B," or, equivalently "at least one of A
and/or B") can refer, in one embodiment, to at least one,
optionally including more than one, A, with no B present (and
optionally including elements other than B); in another embodiment,
to at least one, optionally including more than one, B, with no A
present (and optionally including elements other than A); in yet
another embodiment, to at least one, optionally including more than
one, A, and at least one, optionally including more than one, B
(and optionally including other elements); etc.
[0268] When the word "about" is used herein in reference to a
number, it should be understood that still another embodiment of
the invention includes that number not modified by the presence of
the word "about."
[0269] It should also be understood that, unless clearly indicated
to the contrary, in any methods claimed herein that include more
than one step or act, the order of the steps or acts of the method
is not necessarily limited to the order in which the steps or acts
of the method are recited.
[0270] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and
the like are to be understood to be open-ended, i.e., to mean
including but not limited to. Only the transitional phrases
"consisting of" and "consisting essentially of" shall be closed or
semi-closed transitional phrases, respectively, as set forth in the
United States Patent Office Manual of Patent Examining Procedures,
Section 2111.03.
* * * * *