U.S. patent application number 17/052804 was filed with the patent office on 2021-03-11 for a system with a dynamic variable size nozzle orifice for three-dimensional printing.
The applicant listed for this patent is ADDLEAP AB, DESKTOP METAL, INC.. Invention is credited to Alexander C. BARBATI, Mats MOOSBERG.
Application Number | 20210069789 17/052804 |
Document ID | / |
Family ID | 1000005240572 |
Filed Date | 2021-03-11 |
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United States Patent
Application |
20210069789 |
Kind Code |
A1 |
MOOSBERG; Mats ; et
al. |
March 11, 2021 |
A SYSTEM WITH A DYNAMIC VARIABLE SIZE NOZZLE ORIFICE FOR
THREE-DIMENSIONAL PRINTING
Abstract
This invention relates to three-dimensional printing. This
invention particularly relates to a system with a dynamic variable
size nozzle orifice for three-dimensional printing of objects based
on crafting and molding techniques, and a method thereof. The
present invention provides a dynamic variable nozzle orifice, where
one embodiment uses a nozzle made of a soft flexible material. The
soft flexible material, such as rubber, latex or silicone, is such
that when the extrusion pressure is high the orifice will enlarge
and allow wider extrusion volume for filling large or wide voids.
In another scenario, when the extrusion pressure is lower the
orifice will be narrower and give precise narrow extrusion to fill
smaller voids. Another embodiment uses a method of controlling the
orifice size which is by a mechanical means independent of the
pressure in the nozzle. Such a method can utilize an iris device
for controlling the size of the orifice. By utilizing the function
of a dynamic orifice size of the nozzle when depositing a crafting
material inside a mold structure as described herein, the printing
time can be reduced without a reduction in detailing abilities.
Subsequently, the systems and methods of the present invention are
useful for fabricating high-quality three-dimensional objects using
a crafting paste and molding techniques.
Inventors: |
MOOSBERG; Mats; (Gothenburg,
SE) ; BARBATI; Alexander C.; (Burlington,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ADDLEAP AB
DESKTOP METAL, INC. |
Gothenburg
Burlington |
MA |
SE
US |
|
|
Family ID: |
1000005240572 |
Appl. No.: |
17/052804 |
Filed: |
May 3, 2019 |
PCT Filed: |
May 3, 2019 |
PCT NO: |
PCT/US2019/030707 |
371 Date: |
November 3, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62666719 |
May 4, 2018 |
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62666798 |
May 4, 2018 |
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62668281 |
May 8, 2018 |
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62668279 |
May 8, 2018 |
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62676331 |
May 25, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29K 2505/00 20130101;
B33Y 10/00 20141201; B33Y 30/00 20141201; B22F 2998/10 20130101;
B33Y 70/00 20141201; B29K 2509/02 20130101; B22F 10/00 20210101;
B29C 64/209 20170801 |
International
Class: |
B22F 3/105 20060101
B22F003/105; B29C 64/209 20060101 B29C064/209; B22F 3/00 20060101
B22F003/00 |
Claims
1. A system for three-dimensional printing of an object comprising
a dynamic variable size nozzle orifice.
2. The system according to claim 1 for three-dimensional printing
of an object from a crafting medium.
3. The system according to claim 1 wherein said nozzle orifice
comprises a soft flexible material.
4. The system according to claim 1 wherein said nozzle orifice
comprises a soft flexible material selected from the group
consisting of rubber, latex or silicone.
5. The system according to claim 1 for extruding a crafting medium
from said nozzle orifice at a pressure from about 200 kPa to about
10 MPa.
6. The system according to claim 1 wherein said nozzle orifice has
a variable diameter from about 0.2 mm to about 5 mm.
7. The system according to claim 1 wherein the variable diameter of
said nozzle orifice is controlled by a mechanical function
independent of the pressure of the crafting medium being extruded
at the nozzle orifice.
8. The system according to claim 7 wherein the diameter of the
nozzle orifice is controlled by an iris device.
9. The system according to claim 2 wherein the crafting medium
comprises: (i) from about 40% to about 80% by volume basis of a
powder selected from metal powders, ceramic powders, and
combinations, thereof; (ii) from about 0.5% to about 10% by volume
of a binder; and (iii) from about 15% to about 60% by volume of an
aqueous solvent.
10. The system according to claim 2 wherein the crafting medium
comprises: (i) from about 40% to about 80% by volume basis of a
powder selected from the group consisting of metal powders, ceramic
powders, and combinations, thereof; (ii) from about 0.5% to about
10% by volume of a binder; and (iii) from about 15% to about 60% by
volume of a non-aqueous solvent.
11. The system according to claim 10 wherein said nonaqueous
solvent is selected from the group consisting of methanol, ethanol,
1-propanol, 2-propanol, acetone, acetaldehyde, ethyl acetate, C2-C4
diols, glycerol, acetonitrile, C4-alcohols, 2-ethoxyethanol,
2-ethyl hexanol, 1,2-dichloroethane, diisopropyl amine, isoamyl
alcohol, propyl acetate, isopropyl acetate, and mixtures
thereof.
12. The system according to claim 9 wherein the metal or ceramic
powder comprises particles having a size in the range from 0.1-100
micrometers.
13. The system according to claim 9 wherein the metal powder is
selected from the group consisting of silver, gold, copper, tin,
nickel, chromium, zinc, tungsten, cobalt, aluminum, molybdenum,
boron, iron, titanium, vanadium, niobium, silicon, manganese,
steel, metal alloys, and combinations thereof.
14. The system according to claim 9 wherein the ceramic powder is
selected from the group consisting of silicon carbide, boron
carbide, aluminum carbide, tungsten carbide, titanium carbide,
tantalum carbide, silicon nitride, boron nitride, aluminum nitride,
titanium nitride, zirconium nitride, steatite, forsterite, alumina,
zircon beryllia, magnesia, mullite, cordierite, aluminum titanate,
zirconia, and combinations thereof.
15. The system according to claim 9 wherein the binder is selected
from the group consisting of organic binders, inorganic binders,
and combinations thereof.
16. The system according to claim 15 wherein the in organic binder
is selected from the group consisting of epoxy, polyurethane,
agar-agar, starch, cellulosic materials, arrow root, Agar (E406),
Alginic acid (E400), Sodium alginate (E401), Carrageenan (E407),
Gum arabic (E414), Gum ghatti, Gum tragacanth (E413), Karaya gum
(E416), Guar gum (E412), Locust bean gum (E410), Beta-glucan,
Chicle gum, Dammar gum, Glucomannan (E425), Mastic gum, Psyllium
seed husks, Spruce gum, Tara gum (E417), Gellan gum (E418), Xanthan
gum (E415), polyethylene oxide, polycarboxylic acids (polyacrylic
acid), polycarboxylates, polyvinyl alcohol, cellulose gum (Aquacel
GSA and Aquacel GSH), hydroxymethyl cellulose, hydroxypropyl
cellulose, carboxymethyl cellulose, and combinations thereof.
17. The system according to claim 15 wherein the inorganic binder
is selected from the group consisting of magnesium oxide, magnesic,
cement, sorel cement, inorganic salts, and combinations
thereof.
18. The system according to claim 9 wherein said aqueous solvent is
selected from the group consisting of water or water in combination
with a non-aqueous solvent selected from the group consisting of
methanol, ethanol, 1-propanol, 2-propanol, acetone, acetaldehyde,
ethyl acetate, C2-C4 diols, glycerol, acetonitrile, C4-alcohols,
2-ethoxyethanol, 2-ethyl hexanol, 1,2-dichloroethane, diisopropyl
amine, isoamyl alcohol, propyl acetate, isopropyl acetate, and
mixtures thereof.
19. A method of three-dimensionally printing an object using the
system of claim 1.
20. A method of three-dimensionally printing an object from a
paste-based crafting medium using the system of claim 2.
21. A three-dimensional object printed using the system of claim
1.
22. A three dimensional object printed using the system of claim 2.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to the field of
three-dimensional (3D) printing. The invention particularly relates
to a system with a dynamic variable size nozzle orifice for
three-dimensional printing of objects based on crafting and molding
techniques and a method thereof. These variable size nozzle
orifices are useful for printing of paste-based crafting media.
BACKGROUND OF THE INVENTION
[0002] Three-dimensional printers are used to build solid models by
performing layer by layer printing of a building material. The
building material can be of different forms, such as a liquid or a
semiliquid at the three-dimensional printhead. For example, a solid
material can be heated and then extruded from a three-dimensional
printer nozzle. The layers of building materials can be solidified
on a substrate. Three-dimensional printer systems can use a fused
filament fabrication (FFF) process (sometimes called a fused
deposition modeling (FDM) process) in which a filament is moved by
a filament moving mechanism, toward a heated zone. The filament can
be melted and extruded on a platform to form a three-dimensional
object. However, the melted filament can adhere to the walls of the
heated printhead, resulting in deformed printed lines. A
commercially available FFF system uses a heated nozzle to extrude a
melted material such as a plastic wire. The starting material is in
the form of a filament which is being supplied from a spool. The
filament is introduced into a flow passage of the nozzle and is
driven to move like a piston inside this flow passage. The front
end, near the nozzle tip, of this piston is heated to become
melted. The rear end or solid portion of this piston pushes the
melted portion forward to exit through the nozzle tip. The nozzle
is translated under the control of a computer system in accordance
with previously generated CAD data that has been sliced into
constituent layers.
[0003] A number of different types of accessories for
three-dimensional printing are described in the prior art. For
example, the following patents are provided for their supportive
teachings and are all incorporated by reference: Prior art
document, U.S. Pat. No. 5,121,329 to S Scott Crump discloses an
apparatus for making three-dimensional physical objects of a
predetermined shape by sequentially depositing multiple layers of
solidifying material on a base member in a desired pattern. The
reference does not appear to disclose the formation of a mold
("mould") or the use of any crafting medium.
[0004] Another prior art document, US20140291886 to Mark et al
discloses three dimensional printers, and reinforced filaments, and
their methods of use. In one embodiment, a void-free reinforced
filament is fed into an extrusion nozzle. The reinforced filament
includes a core, which may be continuous or semi-continuous, and a
matrix material surrounding the core. The reinforced filament is
heated to a temperature greater than the melting temperature of the
matrix material and less than the melting temperature of the core
prior to extruding the filament from the extrusion nozzle. The
three-dimensional printer further includes a heating element which
is used to heat the core and/or surrounding material.
[0005] Yet another prior art document, US20150314532 to Mark Gordon
discloses manufacturing of inter-layer bonding in objects by
three-dimensional printing techniques using one or more targeted
heat sources (THSs) that preheat a targeted portion of an existing
object material before additional material is added to the object.
Three-dimensional printing is also improved, optimized or
calibrated by pre- or post-heating of a targeted area. THS elements
may be fixed, mobile, or a combination thereof to apply heat to
targeted areas. In some embodiments a single print head may have
multiple print nozzles. The print nozzle emits or deposits material
fed through the print head. The print nozzle may be any suitable
material, e.g., brass. The print nozzle may have one or more
orifices to emit the printing material. However, this prior art
document does not appear to discuss a dynamic variable nozzle
orifice or the use of a crafting material paste.
[0006] Yet another prior art document, US20150174824 to Gifford
discloses a modular three-dimensional printer system including a
base subsystem and multiple exchangeable components. The base
subsystem can have a three-dimensional motion module, a printhead
module and a platform module. The multiple exchangeable components
can include printheads having different configurations and
functionalities, which can be exchangeably installed in the
printhead module. In one of these embodiments, the system has a
radiant heat source, which is located on a moving printhead to
focus the heat in the area that is about to be fused. The heated
substrate can increase the penetration of the bond between the
substrate and the freshly deposited material. This document does
not appear to discuss the use of a dynamic variable nozzle orifice
for fabricating stronger bonds between the layers.
[0007] Yet another prior art document, US20160325498 to Daniel
Gilbert discloses a three-dimensional printer based on a
two-dimensional staggered nozzle array for depositing each layer in
a raster scan mode. Each nozzle contains an individually controlled
mechanical high-speed valve. Multiple nozzles are fed from a
constant pressure reservoir, typically containing a molten polymer.
However, this prior art document does not appear to discuss the use
of a variable size or dynamic nozzle orifice for fabrication by
layer-by-layer three-dimensional printing.
[0008] Yet another prior art document, US20080042321 to Russell et
al. discloses an apparatus and methods for producing
three-dimensional objects and auxiliary systems used in conjunction
therewith. The apparatus and methods involve continuously printing
radially about a circular and/or rotating build table using
multiple printheads. The apparatus and methods also include
optionally using multiple build tables. The auxiliary systems
relate to build material supplies, printhead cleaning, diagnostics,
and a monitoring operation of the apparatus. This prior art
document discusses the concept of inducing a pressure differential
for dispensing the binder through the nozzles. However, this prior
art document fails to disclose varying the nozzle orifice size by
changing the pressure flow.
[0009] Yet another prior art document, U.S. Pat. No. 8,475,946 to
Dion et al. discloses a method of preparing a ceramic precursor
article, a ceramic precursor made thereby, a method of making a
ceramic article, and a ceramic article made by that method. It also
includes a method of replicating a ceramic shape. This prior art
document describes that one of the main challenges of the use of
ceramic products with modern technologies is its reduction factor
(shrinkage). Depending on the process used, e.g., such as drying,
firing or hot pressing, a ceramic object can shrink by as much as
20 percent. Such shrinkage can be undesirable if the nature of the
ceramic article requires precise dimensional control.
[0010] A non-patent literature prior art document, a Master degree
thesis of Brady Godbey discloses surface finish control for
three-dimensional printed metal tooling. The document reports that
the tip orifice diameter of a nozzle may vary and will affect build
speed and quality. Depending on the tip and build parameters, the
minimum feature size ranges from 0.016 inches to 0.024 inches and
the layer thickness may range from 0.005 inches to 0.013 inches.
Despite its capability for small features, the manufacture of tall
thin projections are not recommended as contact of the nozzle tip
with the previously deposited layers may distort the part. However,
this prior art document fails to provide a solution for depositing
the layer without distortion using a single dynamic variable nozzle
orifice.
[0011] Yet another prior art document, SE1500245 to Mats Moosberg
discusses a three-dimensional imaging process for making objects,
preferably metal objects or ceramic objects, on a layer-by-layer
basis under the control of a data processing system. The process
also includes the use of a filament material (in the form of a
solid that melts to a fluid during the printing process) to build
the mold and a crafting medium (in the form of a paste) for filling
the hollow mold cavity. The method for building the
three-dimensional model by extruding a crafting medium in parallel
with a molding material as described in the prior art document,
SE1500245, requires that it is sometimes necessary to fill thin
whereas at other times it is necessary to fill out the large voids
in layer-by-layer three-dimensional printing. Further, it also
requires that the paste deposited on the layer is flat. For
example, it requires filling very thin voids in a layer and to
build thin walls, the paste extruder orifice needs to be small.
However, a small orifice on the nozzle means that it can be
difficult to fill large voids in an efficient way. Also, when the
paste is extruded in a layer there is a need to make ensure that
the paste in the layer is flat. This prior art document fails to
provide the solution of the present invention for such cases.
[0012] However, the above mentioned references have one or more of
the following shortcomings: (a) not discussing molding techniques;
(b) not discussing the use of a building or crafting medium; (c)
requiring multiple printheads with different size nozzles; (d)
requiring nozzles with different size orifices; (e) the finishing
of the final three-dimensional printed object is not of sufficient
quality; and (f) none of the references discuss dynamic variable
nozzle orifices comprising a soft flexible material.
[0013] It should be appreciated that during the three-dimensional
layer-by-layer deposition of a crafting material paste, there can
be two different problematic situations that can arise. In the
first situation--where there are small voids requiring filling and
the nozzle orifice is wider than the voids, the paste material
being deposited can be spilled outside the voids. In the second
situation--where there are large voids requiring filling and the
nozzle orifice is small, then deposition will be ineffective
because only a small amount of paste can be extruded through the
small orifice. A solution to these two problematic situations is
achieved by the dynamic variable nozzle orifice of the present
invention. To construct a dynamic variable nozzle orifice, for
example a soft flexible material, such as rubber, latex or silicone
can be used. Such a dynamic variable nozzle would function such
that when the extrusion pressure of the material being deposited is
high the orifice will enlarge and allow for a wider extrusion flow
and greater volume for filling, for example, large or wide voids.
In another scenario, when the extrusion pressure is lower, the
orifice will be narrower and provide a precise narrower extrusion
to fill small voids. The hole size of the orifice can by this
method is controlled by changing the pressure in the nozzle.
[0014] Another method of controlling the orifice size can be by a
separate control mechanical function that is independent of the
pressure at the nozzle. Such a method can be a iris type of device
which can provide a range of orifice diameters at the nozzle tip.
Both of these types of nozzles, i.e. the pressure-dependent
variable dynamic nozzle and the independently controlled dynamic
nozzle, and their delivery of crafting media, such as paste-based
crating media, are embodiments of the present invention
[0015] By utilizing the function of a dynamic orifice size of the
nozzle when depositing a crafting material inside a mold structure
as described here, the printing time can be reduced without a
reduction in resolution or detailing abilities.
[0016] The present application addresses the above-mentioned
concerns and short comings with regard to providing an improved
system for depositing a construction material for three-dimensional
printing and filling variable size voids by using a dynamic
variable nozzle orifice.
SUMMARY OF THE INVENTION
[0017] The present invention relates to three-dimensional printing
and in particular to a system and method of printing with a dynamic
variable size nozzle orifice for printing objects based on crafting
and molding techniques, and a method thereof. In some embodiments
the present invention provides a dynamic variable nozzle orifice
which is made up of soft flexible material, wherein the diameter of
the nozzle orifice is controlled by varying the pressure of the
material being extruded through the nozzle. In other embodiments
the present invention provides a nozzle orifice whose diameter is
varied by a mechanical function that is separately controlled
independently of the pressure of the material being extruded
through the nozzle.
[0018] The present invention relates to a system for
three-dimensional printing of an object comprising a dynamic
variable size nozzle orifice.
[0019] In further embodiments the present invention relates to a
system for printing of a three-dimensional object from a crafting
medium.
[0020] In further embodiments the present invention relates to an
orifice comprising a soft flexible material.
[0021] In further embodiments the present invention relates to an
orifice comprising a soft flexible material selected from the group
consisting of rubber, latex or silicone.
[0022] In further embodiments the present invention relates to an
orifice for extruding a crafting medium at a pressure from about
200 kPa to about 10 MPa.
[0023] In further embodiments the present invention relates to an
orifice having a variable diameter from about 0.05 mm to about 20
mm, and in other embodiments from about 0.2 mm to about 5 mm. It is
contemplated that the diameter of the orifice can be varied
depending upon the pressure at which the crafting medium is
extruded and also upon the viscosity of the crafting medium. For
example, at 500 kPa the orifice is 0.2 mm in diameter, at 2 MPa the
orifice is 1 mm in diameter, at 3MPa the orifice is 2 mm in
diameter, and at 5 MPa the orifice is 5 mm in diameter.
[0024] In further embodiments the present invention relates to an
orifice controlled by a mechanical function independent of the
pressure at the nozzle.
[0025] In further embodiments the present invention relates to an
orifice wherein the diameter of the orifice is controlled by an
iris device.
[0026] In further embodiments the present invention relates to a
system wherein the crafting medium comprises: [0027] (i) from about
40% to about 80% by volume basis of a powder selected from metal
powders, ceramic powders, and combinations, thereof; [0028] (ii)
from about 0.5% to about 10% by volume of a binder; and [0029]
(iii) from about 15% to about 60% by volume of an aqueous
solvent.
[0030] In further embodiments the present invention relates to a
system wherein the crafting medium comprises: [0031] (i) from about
40% to about 80% by volume basis of a powder selected from metal
powders, ceramic powders, and combinations, thereof; [0032] (ii)
from about 0.5% to about 10% by volume of a binder; and [0033]
(iii) from about 15% to about 60% by volume of a non-aqueous
solvent.
[0034] In further embodiments the present invention relates to a
crafting medium wherein the metal or ceramic powder comprises
particles having a size in the range from 0.1-100 micrometers.
[0035] In further embodiments the present invention relates to a
crafting medium wherein the metal powder is selected from silver,
gold, copper, tin, nickel, chromium, zinc, tungsten, cobalt,
aluminum, molybdenum, boron, iron, titanium, vanadium, niobium,
silicon, manganese, steel, metal alloys, and combinations
thereof.
[0036] In further embodiments the present invention relates to a
crafting medium wherein the ceramic powder is selected from silicon
carbide, boron carbide, aluminum carbide, tungsten carbide,
titanium carbide, tantalum carbide, silicon nitride, boron nitride,
aluminum nitride, titanium nitride, zirconium nitride, steatite,
forsterite, alumina, zircon beryllia, magnesia, mullite,
cordierite, aluminum titanate, zirconia, and combinations
thereof.
[0037] In further embodiments the present invention relates to a
crafting medium wherein the binder is selected from organic
binders, inorganic binders, and combinations thereof.
[0038] In further embodiments the present invention relates to a
crafting medium wherein the in organic binder is selected from
epoxy, polyurethane, agar-agar, starch, cellulosic materials, arrow
root, Agar (E406), Alginic acid (E400), Sodium alginate (E401),
Carrageenan (E407), Gum arabic (E414), Gum ghatti, Gum tragacanth
(E413), Karaya gum (E416), Guar gum (E412), Locust bean gum (E410),
Beta-glucan, Chicle gum, Dammar gum, Glucomannan (E425), Mastic
gum, Psyllium seed husks, Spruce gum, Tara gum (E417), Gellan gum
(E418), Xanthan gum (E415), polyethylene oxide, polycarboxylic
acids (polyacrylic acid), polycarboxylates, polyvinyl alcohol,
cellulose gum (Aquacel GSA and Aquacel GSH), hydroxymethyl
cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, and
combinations thereof.
[0039] In further embodiments the present invention relates to a
crafting medium wherein the inorganic binder is selected magnesium
oxide, magnesic, cement, sorel cement, inorganic salts, and
combinations thereof.
[0040] In further embodiments the present invention relates to a
crafting medium wherein said aqueous solvent is selected from
water, or water in combination with one or more non-aqueous
solvents selected from the group consisting of methanol, ethanol,
1-propanol, 2-propanol, acetone, acetaldehyde, ethyl acetate, C2-C4
diols, glycerol, acetonitrile, C4-alcohols, 2-ethoxyethanol,
2-ethyl hexanol, 1,2-dichloroethane, diisopropyl amine, isoamyl
alcohol, propyl acetate, isopropyl acetate, and mixtures thereof.
Also, contemplated are azeotropes.
[0041] In further embodiments the present invention relates to a
crafting medium comprising a non-aqueous solvent instead of an
aqueous solvent, such nonaqueous solvents selected from the group
consisting of methanol, ethanol, 1-propanol, 2-propanol, acetone,
acetaldehyde, ethyl acetate, C2-C4 diols, glycerol, acetonitrile,
C4-alcohols, 2-ethoxyethanol, 2-ethyl hexanol, 1,2-dichloroethane,
diisopropyl amine, isoamyl alcohol, propyl acetate, isopropyl
acetate, and mixtures thereof.
[0042] In further embodiments the present invention relates to a
method of three-dimensional printing an object using the system of
the present invention.
[0043] In further embodiments the present invention relates to a
three-dimensional object printed using the system of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The invention will be better understood and objects other
than those set forth above will become apparent when consideration
is achieved to the following detailed description thereof. Such
description makes reference to the annexed drawings wherein:
[0045] FIG. 1 depicts a schematic representation of the system in
accordance with the present invention.
[0046] FIG. 2A depicts exploded views of the dynamic flexible
nozzle orifice of the system, at high pressure, in accordance with
the present invention.
[0047] FIG. 2B depicts exploded views of the dynamic flexible
nozzle orifice of the system, at low pressure, in accordance with
the present invention.
[0048] FIG. 3A depicts the extrusion of a crafting paste into a
wide void defined by a molding layer, with a dynamic variable
flexible nozzle orifice.
[0049] FIG. 3B depicts the extrusion of a crafting paste into a
narrow void defined by a molding layer, with a dynamic variable
flexible nozzle orifice.
[0050] FIG. 4 illustrates a flow chart for an example of a method
for generating a mold and then printing a three-dimensional object
in accordance with the present invention.
[0051] FIG. 5 shows a soft flexible variable dynamic nozzle with
the nozzle in a non-expanded mode defining a small orifice.
[0052] FIG. 6 shows a soft flexible variable dynamic nozzle with
the nozzle in an expanded mode defining a large orifice.
[0053] FIG. 7 shows a variable dynamic nozzle with a mechanical
iris type device to control the orifice diameter. A separate
control mechanism for the iris device is not shown.
DETAILED DESCRIPTION OF THE INVENTION
[0054] In the following detailed description, reference is made to
the accompanying drawings which form a part hereof, and in which
are shown by way of illustration specific embodiments in which the
invention can be practiced. These embodiments are described in
sufficient detail to enable those skilled in the art to practice
the invention, and it is to be understood that the embodiments can
be combined, or that other embodiments can be utilized and that
structural and logical changes can be made without departing from
the spirit and scope of the present invention. The following
detailed description is, therefore, not to be taken in a limiting
sense.
[0055] Many Rapid Prototype processes have been developed in recent
years and many more are currently being researched, but until
recently, few of them have been used to fabricate paste or
clay-based objects. Methods of three-dimensional printing using
clay or ceramic materials and preparing molds are also known in the
prior art documents. With three-dimensional printing techniques for
fabricating objects on a layer-by-layer basis, it is very important
to have good integration or inter-layer bonding within the objects.
Due to undesired void formation, the inter-layer bonding might not
be as strong as required and the resultant three-dimensional object
quality can be compromised. Furthermore, different size voids can
also form during or after the printing process. However, filling
these voids with crafting paste material using a single size
orifice can be problematic. Either one has to use multiple
printheads with multiple nozzles having different nozzle orifice
diameters for the same material or one has to switch nozzles.
During the three-dimensional layer-by-layer printing by depositing
crafting material pastes, there can be two different situations:
(i) First situation--when there are small voids required to be
filled out and the nozzle orifice is wider than the voids, then the
crafting paste material can spill or flow outside the voids; (ii) n
the second situation--if there are large voids needed to be filled
out and the nozzle orifice is small, then deposition of the
crafting paste can be ineffective and only a small amount of paste
can be extruded through the small orifice, which can be
time-consuming. The present invention provides a solution in
certain embodiments to solve the problem of filling different size
voids and building strong inter-layer bonding by using a single,
dynamic flexible nozzle orifice. The dynamic flexible nozzle
orifice of the present invention is made up of a soft flexible
material, so the orifice diameter can be varied by changing the
extrusion pressure. In other embodiments, the present invention
provides a solution by providing a dynamic nozzle orifice that is
controlled by an external means. An example of such a dynamic
nozzle orifice is an iris type of orifice.
[0056] FIG. 1 depicts a schematic representation of a system for
filling variable size voids by using a dynamic variable nozzle
orifice which is made up of soft flexible material according to one
of the embodiments of the present invention. The system 100 for
drying a paste based crafting model during three-dimensional
printing comprises: (a) supply arrangement for a filament material
101 for forming a mold layer for the object; (b) an extruder 103;
(c) a feeding channel 106; (d) a plurality of nozzles 107 and 113;
(e) a plurality of heating elements/systems 108 for melting the
filament and 119 for drying the crafting medium; (f) a plurality of
discharge orifices 109 and 114; (g) a supply arrangement for a
crafting medium 110; (h) an actuator 112 for controlling the flow
of the crafting medium; (i) a mold 116 (formed from the
layer-by-layer deposition of the filament material); and (j) a
platform 115 on which the system of the three-dimensional printer
is fixed. The system has dual printhead which comprise a first
dispensing nozzle 107 for depositing the filament 102 in flowable
fluid form by the discharge orifice 109 to supply a filament 102 or
a first material layer and a second dispensing nozzle 113 for
depositing a crafting medium 111 or the second material layer which
is in a paste form by the discharge dynamic variable nozzle orifice
114. The dynamic variable nozzle orifice 114 can be made up of a
soft material, such as rubber, latex or silicone. In other
embodiments the dynamic variable nozzle orifice can comprise an
orifice that is controlled by an external device and is an
iris-type shutter orifice. The system further comprises a holding
element 118 which holds a dual printhead and a heating
element/system 119.
[0057] A filament feeding device comprising a stepper motor (not
shown) and idler and driving rollers 104 and 105 located opposite
to drive rollers which work together to grip the filament there
between and to advance it through a filament feeding channel 106
thereby regulating the flow of filament through the feeding
channel. The extruder 103 can be of any different type such as
roller, gear system, etc. The heating system 121 can consist of a
radiating heater, and possibly an air circulation fan. The heating
system may also have connectors 120, which can be of electric wire
or pipes/tubes for blowing air. The heating system can also provide
cooling or can reduce the temperature and can function as a
temperature control system. Further, the temperature control system
can include without limitation one or more of a heater, coolant, a
fan, a blower, or the like.
[0058] As shown in the FIG. 1, a system 100 in accordance with a
preferred embodiment of the present invention comprises a supply
101 of filament material such as acrylonitrile butadiene-styrene
(ABS) or Polylactic acid (PLA); a filament feeding device
comprising a stepper motor (not shown), idler rollers 104 located
opposite to drive rollers 105 which work together to grip the
filament there between and to advance it through a filament feeding
channel 106 thereby regulating the flow of filament through the
feeding channel 106. The feeding channel 106 is made of a material
having low thermal conductivity, such as for example Teflon. The
system further includes a first dispensing nozzle 107, preferably
made of a material with a thermal conductivity greater than 25
W/(mK), such as for example brass or similar metallic alloys. The
first dispensing nozzle 107 can be heated to a temperature
sufficiently high for the filament 102 to liquify. Heating elements
108, in the form of a resistance heating tape or sleeve, and a
temperature sensor (not shown) are arranged around a lower portion
of the nozzle 107 to regulate the temperature of the nozzle 107 to
a temperature of approximatively 200.degree. C. to 240.degree. C.
to convert a leading portion of the filament 102 into a flowable
fluid state. The solid (un-melted) portion of the filament 102
inside the feeding channel 106 acts like a piston to drive the
melted liquid for dispensing through a first discharge orifice 109.
The drive motor (not shown) can be controlled to regulate the
advancing rate of the filament 102 in the feeding channel 106 so
that the volumetric dispensing rate of the fluid can be closely
controlled.
[0059] The filament material is preferably a thermoplastic polymer
that softens and liquifies for easy deposition and which rapidly
cools and hardens to provide a suitable mold. Thermoplastic
polymers useful for forming the mold from the filament material can
include the following: poly(propylene), poly(styrene), poly(lactic
acid) (PLA), acrylonitrilebutadiene-styrene (ABS), polycarbonate
abs (PC-ABS), nylon, poly(carbonate), poly(phenyl sulfone), ultem,
poly(ethylene), acrylic [poly(methyl methacrylate)],
poly(benzimidazole), poly(ether sulfone), poly(etherether ketone),
poly(etherimide), poly(phenylene oxide), poly(phenylene sulfide),
poly(vinyl chloride), poly(vinyldiene fluoride), poly(acetal),
poly(vinyl acetate), poly(vinyl butyrate), poly(vinyl alcohol),
poly(4-hydroxystyrene), poly(vinyl formate), poly(vinyl stearate),
poly(acrylamide), poly(caprolactone), chitosan and combinations
thereof.
[0060] As shown in the FIG. 1, the apparatus further includes a
supply 110 of a crafting medium 111, such as for example a metal
clay or a ceramic clay. In a preferred embodiment of the invention,
the crafting medium 111 comprises microscopic metal particles of
metal, such as silver, gold, copper or alloys or combinations
thereof, mixed with an organic binder and water. The supply 110 is
preferably shaped as a conventional clay extruder comprising a
cylindrical cavity and valve means 112 to control and regulate the
flow of crafting medium toward a second dispensing nozzle 113 and
through a second discharge orifice 114.
[0061] Both nozzles 107 and 113 are arranged at a predetermined
distance from an object supporting platform 115. The dual printhead
and the platform 115 are moved relative to one another in a
movement pattern corresponding to a predetermined object 117. The
fused filament is deposited through the first discharge orifice 109
while the dual printhead is moving in an X-Y-plane relative to the
platform 115, to build one layer of a mold 116. Thereafter, the
crafting medium 111 is deposited while the dual printhead is moving
in an X-Y-plane relative to the platform 115 in order to fill the
layer of the mold 116.
[0062] The crafting medium 111 is in the paste form. The layer of
the crafting medium is required to be dried immediately, or a short
time interval after printing, but in any event prior to the
printing of the next crafting medium layer. The system 100 includes
the heating system or drying apparatus 119 which can be connected
on the printhead. The heating system is used for drying a paste of
the crafting medium 111. This drying is accomplished by moving
print head and it is possible after finishing each layer of the
object (both mold and paste), to have the print head repeatedly
scan the printed layer and apply heat and air circulation to
improve drying in a controlled way. The drying apparatus can
comprise a radiating heater, and possibly an air circulation fan.
This can enable better evenness in the drying and reduce risks for
cracks and also reduces problems in the next steps.
[0063] Thereafter the dual printhead and the platform 115 are
displaced in the Z-direction from one another by a distance
corresponding to the thickness of a single layer so that the next
layer can be deposited. The first and second dispensing nozzles 107
and 113 are used to deposit the melted filament and the crafting
medium respectively and to alternate the deposition on a layer by
layer basis, in such a manner that the mold is alternately built
and then filled with crafting medium for each layer. When the
deposition is achieved, the object 117 is embedded inside the mold
116. The mold 116 will thereafter be removed in order to release
the object 117. That removal step is preferably achieved by heating
the mold 116 to a temperature of approximately 200.degree. C. until
the mold building material is melted away from the object 117. If
the object 117 is made of metal clay, the metal contained in the
object 117 is thereafter sintered to obtain a pure metal
object.
[0064] In an alternate embodiment of the present invention, the
apparatus further includes a heating means (not shown) for heating
and melting the mold 116. Such heating means can consist of an
insulated chamber, or an oven, inside which the mold 116 is exposed
to heat energy to release the object 117.
[0065] A first supply of filament material used to build the mold.
The supply of filament can comprise a rotatable spool on which the
filament is wound. Such a filament material can be comprised of,
but is not limited to, one or more of the following materials
including various waxes, thermoplastic polymers, thermoset
polymers, and combinations thereof. However, the primary modeling
material preferably comprises an organic polymer with a reasonably
low softening or melting point, e.g.,
acrylonitrile-butadiene-styrene (ABS) or Polylactic acid (PLA). As
described above, thermoplastic polymers useful for forming the mold
from the filament material can include the following:
poly(propylene), poly(styrene), poly(lactic acid) (PLA),
acrylonitrilebutadiene-styrene (ABS), polycarbonate abs (PC-ABS),
nylon, poly(carbonate), poly(phenyl sulfone), ultem,
poly(ethylene), acrylic [poly(methyl methacrylate)],
poly(benzimidazole), poly(ether sulfone), poly(etherether ketone),
poly(etherimide), poly(phenylene oxide), poly(phenylene sulfide),
poly(vinyl chloride), poly(vinyldiene fluoride), poly(acetal),
poly(vinyl acetate), poly(vinyl butyrate), poly(vinyl alcohol),
poly(4-hydroxystyrene), poly(vinyl formate), poly(vinyl stearate),
poly(acrylamide), poly(caprolactone), chitosan and combinations
thereof.
[0066] A second supply of crafting medium can be in paste form.
Such a medium can comprise silicone, a ceramic material or the
like. The crafting medium is preferably a commercially available
metal clay usually comprising very small particles of metal such as
silver, gold, bronze, or copper mixed with an organic binder and
water commonly used in making jewelry, beads and small
sculptures.
[0067] FIG. 2A depicts exploded views of the dynamic flexible
nozzle orifice of the system, at high pressure, in accordance with
the present invention. FIG. 2B depicts exploded views of the
dynamic flexible nozzle orifice of the system, at low pressure, in
accordance with the present invention. The dynamic flexible nozzle
orifice 14 for the second print head is made up of soft material.
When the extrusion pressure is high (201A) to deposit the crafting
paste material, the dynamic flexible nozzle orifice 14 is
compressed and it widens the orifice 202A. Further, when the
extrusion pressure is low (201B) to deposit the crafting paste
material, the dynamic flexible nozzle orifice 114 is not
compressed, then the orifice diameter is narrower 202B.
[0068] The present invention how it works while filling out the
crafting paste materials at different sizes of the voids during
mold extrusion step is also clearly depicted in the FIG. 3A and
FIG. 3B. FIG. 3A depicts mold extrusion step (302) at higher
pressure 301A for filling or depositing wide void 303A with paste
by widening a dynamic flexible nozzle orifice. FIG. 3B depicts mold
extrusion step 302 at lower pressure 301B for filling or depositing
narrow void 303B with paste by narrowing a dynamic flexible nozzle
orifice. The wide void is needed to be filled during mold extrusion
step, the extrusion pressure is increases, and it compresses the
dynamic flexible nozzle orifice. The more paste material is
extruded from the nozzle orifice by widening the diameter of the
orifice (FIG. 3A). The nozzle and the dynamic flexible nozzle
orifice have geometry to smoothen the paste extrusion 304. During
the deposition of the crafting material, it is require controlling
the top surface of the extruded paste a flattening geometry, this
flattening geometry will control the height of the extruded paste
and make sure it completely fills the void. In other situation,
when the small voids are require filling out during the mold
extrusion step, the extrusion pressure is lowered, and it would not
have effect on the dynamic flexible nozzle orifice. The only
required paste material will be extruded from the nozzle orifice by
narrow diameter of the orifice (FIG. 3B).
[0069] FIG. 4 illustrates by a flow chart an example of a method
for generating mold and then printing a three-dimensional object in
accordance with the present invention. The method starts with
providing three-dimensional model to the computer or any digital
media, at block 401. Then digitally generating mold at block 402.
At block 403, combining digitally generated mold and
three-dimensional model. This step is one of the important steps of
the present invention, it compares the three dimensional parameters
of the digitally generated mold and three-dimensional model.
[0070] Then the system generates the detailed tool paths and
extrusion instructions at block 404. The system also calculates and
generates instructions for giving the correct paste extruder
pressure in combination with a wanted extrusion width. The system
also finalizes the thickness of the mold required and it selects
the as thin as possible. The thickness of the mold surface, i.e.
the mold skin thickness can be about 0.1 to about 10 mm. Further,
the holes are made up of having a diameter from about 0.1 to about
0.4 mm. The holes should be evenly distributed over the mold
surface. Then the instructions are sending to the printer or a
system (as explained above and depicted in FIG. 1). Then the
apparatus/printer starts printing of the combined mold and
three-dimensional model layer by layer, at block 406. At block 407,
extruding and depositing a mold material (filament material) with
structural additive and crafting material in a layer by layer form.
In block 407, there are several sub-steps involved (which are not
depicted in the FIG. 3): such as providing a supply of mold
building material in filament form; feeding the filament to enter
one end of a flow passage of the first dispensing nozzle having a
first discharge orifice on another end; heating the first
dispensing nozzle to convert a leading portion of the filament
therein to a flowable fluid; and dispensing the flowable fluid
through the first discharge orifice to an object-supporting
platform. Further, in block 407, there are several sub-steps
involved: such as providing a supply of crafting medium in paste
form; feeding the crafting medium to enter one end of a flow
passage of the second dispensing nozzle having a second discharge
orifice on another end; and during the dispensing step, operating
the second dispensing nozzle for extruding the crafting medium on a
layer.
[0071] Next at block 408, thereafter the dual printhead and the
platform are displaced in the Z-direction from one another by a
distance corresponding to the thickness of a single layer so that
the next layer can be deposited. Next at block 409, if the printing
of the all layers, meaning that the crafted object and mold is
complete then it moves to the next step, block 410. Otherwise, the
process starts repeats from block 407 until the entire object is
completed.
[0072] At block 410, processing step involves the removing of the
mold material. The mold material can be removed by for example
burning or melting or by chemical, and all of these processes are
easier if thinner layer. The next processing step is to remove the
binder material at block 411. At block 412, the crafting material
is transformed to the final finished product.
[0073] Further, in an alternate example, the molding material can
also include the structural additive such as metal, charcoal
particles, ceramic, or other particles. The material of the mold
material with structural additive is such that it prevents the
fusing of the object (crafting layer) with the support structure
material. In another scenario, the material of the structural
additive also prevents fusing between one part of the object with
another part of the object to create gap or space between them.
[0074] The present invention relates to a three-dimensional imaging
process for making objects, preferably metal objects or ceramic
objects, on a layer-by-layer basis under the control of a data
processing system. Some of the process steps which are not included
above in detail are: (a) providing a dual printhead including a
first dispensing nozzle and a second dispensing nozzle; (b) during
the dispensing step, moving the dual printhead and the
object-supporting platform relative to one another in a plane
defined by first and second directions and in a third direction
orthogonal to said plane to form the flowable fluid into a
three-dimensional hollow pattern having a molding cavity shaped in
accordance with a predetermined three dimensional object; (c) by
layer basis through the second discharge orifice onto the
three-dimensional hollow pattern in order to gradually fill the
molding cavity, thereby forming the predetermined three-dimensional
object; and (d) removing the three-dimensional hollow pattern in
order to release the predetermined three-dimensional object.
[0075] Crafting Medium
[0076] Although a wide variety of crafting media can be used with
the methods and systems of the present invention, a particularly
useful crafting medium contains a very low concentration of the
binder organic base materials, such as starches, cellulose,
cellulose derivatives, agar, etc., and around 15 to 60 volume %
water. The binding organic base material content can be varied from
1 to 10 volume %. The binder can act as glue between the powder
particles, and also as filler between the particles. The method of
preparation of the three-dimensional object also includes the step
of drying on a layer-by-layer basis. The drying is a continuous
process in the present invention and can remove most of the water
and/or other solvents or carriers from the binder composite
material from each layer after depositing.
[0077] An exemplary crafting material useful herein comprises:
(i) from about 40% to about 80% by volume basis of a powder
selected from metal powders, ceramic powders, and combinations,
thereof; (ii) from about 0.5% to about 10% by volume of a binder;
and (iii) from about 15% to about 60% by volume of an aqueous
solvent.
[0078] An exemplary crafting material useful herein comprises:
(i) from about 40% to about 80% by volume basis of a powder
selected from metal powders, ceramic powders, and combinations,
thereof; (ii) from about 0.5% to about 10% by volume of a binder;
and (iii) from about 15% to about 60% by volume of a non-aqueous
solvent.
[0079] Another crafting material useful herein comprises,
(i) from about 60% to about 70% by volume basis of a powder; (ii)
from about 1% to about 5% by volume of a binder; and (iii) from
about 25% to about 35% by volume of an aqueous solvent.
[0080] Another crafting material useful herein comprises,
(i) from about 60% to about 70% by volume basis of a powder; (ii)
from about 1% to about 5% by volume of a binder; and (iii) from
about 25% to about 35% by volume of a non-aqueous solvent.
[0081] The solvent or carrier for the crafting material can be an
aqueous solvent. Such an aqueous solvent can be solely or primarily
water, or can comprise other solvent materials which are generally
water miscible. In other embodiments, a nonaqueous solvent or
mixtures of non-aqueous solvents can be employed. Such non-aqueous
solvents can be selected from the group consisting of methanol,
ethanol, 1-propanol, 2-propanol, acetone, acetaldehyde, ethyl
acetate, C2-C4 diols, glycerol, acetonitrile, C4-alcohols,
2-ethoxyethanol, 2-ethyl hexanol, 1,2-dichloroethane, diisopropyl
amine, isoamyl alcohol, propyl acetate, isopropyl acetate, and
mixtures thereof. Also, contemplated are azeotropes.
[0082] In further embodiments the present invention relates to a
crafting medium comprising a non-aqueous solvent instead of an
aqueous solvent, such nonaqueous solvents selected from the group
consisting of methanol, ethanol, 1-propanol, 2-propanol, acetone,
acetaldehyde, ethyl acetate, C2-C4 diols, glycerol, acetonitrile,
C4-alcohols, 2-ethoxyethanol, 2-ethyl hexanol, 1,2-dichloroethane,
diisopropyl amine, isoamyl alcohol, propyl acetate, isopropyl
acetate, and mixtures thereof.
[0083] Several materials can be used as the leaving component, i.e.
the solvent or carrier, in the deposition technique involving
continuous, layer-by-layer drying. One example of a departing
component is water, with a vapor pressure of about 2.4 kPa. Higher
vapor pressures, i.e. low boiling points, are in general preferred,
as they will require less energy to drive away from the deposited
part. However, including materials with vapor pressures which are
very high as compared to water (acetaldehyde, for example) can in
some instances cause difficulties with layer-to-layer and
strand-to-strand bonding if the leaving component departs prior to
the formation of a significant bond. In this case controlled
drying, achieved via depression of the print temperature, can be
employed during formation of the object. After formation of the
object, the temperature (or other thermodynamic variable) can be
changed to complete the removal of the leaving component.
[0084] Solvents used can be aqueous (e.g., water, and water with
salts or surfactants), organic and primarily carbon based solvents,
and organic solvents with halogen groups, fluorinated organic
solvents, or mixtures of any of those aforementioned items.
Mixtures of components may be chosen such that when the components
leave the part, the components leave in a proportion identical or
substantially similar to the proportion of the components in the
deposited material.
[0085] In addition to the list provided below, materials such as
dichloroethane, diiodoethane, fluorinated or chlorinated
refrigerants, or degreaser materials as manufactured by DuPont
(Operteron) or MicroCare (Tergo) can be used. Further, solvent
drying specialty fluids added to liquids such as water or ethanol
(and their mixtures), can be used. Such a solvent drying specialty
fluid is Vertrel XP10 Solvent Drying Specialty fluid by
MicroCare.
[0086] In the three-dimensional printing process, it is necessary
to use binders to provide rigidity to the crafting medium of the
object during fabrication. Different types of binding materials can
be used in these three-dimensional printing processes. Organic
binders, such as epoxy, polyurethane, agar-agar, starch, cellulosic
materials, Agar (E406), Alginic acid (E400), Sodium alginate
(E401), Carrageenan (E407), Gum arabic (E414), Gum ghatti, Gum
tragacanth (E413), Karaya gum (E416), Guar gum (E412), Locust bean
gum (E410), Beta-glucan, Chicle gum, Dammar gum, Glucomannan
(E425), Mastic gum, Psyllium seed husks, Spruce gum, Tara gum
(E417), Gellan gum (E418), Xanthan gum (E415), polyethylene oxide,
polycarboxylic acids (polyacrylic acid), polycarboxylates,
polyvinyl alcohol, cellulose gum (Aquacel GSA and Aquacel GSH),
hydroxymethyl cellulose, hydroxypropyl cellulose, Carboxymethyl
cellulose, etc. can be used while Inorganic binders, such as
magnesium oxides, magnesic, cement, sorel cement, salts, etc. are
used.
[0087] The three-dimensional objects with a powder plus binder
constitution for sintering can pose several problems. The binder
can be difficult to remove because it needs to be dissolved or
burned out after the object is finished. The binder can also be
hazardous and or can require toxic substances to dissolve it away.
While removing the binder there is a risk for developing cracks and
deformities in the resulting object. Furthermore, methods of
three-dimensional printing using clay or ceramic materials and
preparing a mold are also well known in the prior art documents.
Most of these prior art documents discusses the drying or heating
of the mold or clay paste post processing. A major problem is
cracking of the deposited object when the drying is carried out at
the end of the full deposition processing. Cracks and unevenness
can develop on the mold or on the object. The present invention is
providing solution to solve these problems of cracks and unevenness
of the object or the mold.
[0088] A solution to this cracking problem is achieved in the
present patent application. This solution is achieved by providing
a crafting medium comprising a metal or ceramic, binder organic
base materials, and water. The crafting medium which is in the
paste form includes 40 volume %-80 volume % metal/ceramic powder, 1
volume %-10 volume % organic base material, and 15 volume %-60
volume % water. The metal or ceramic powder particle size is in the
range from 0.1-100 micrometers.
[0089] In another embodiment of the invention, the crafting medium
comprises microscopic particles of a metal, such as silver, gold,
copper, tin, nickel, chromium, zinc, tungsten, cobalt, aluminum,
molybdenum, boron, iron, titanium, vanadium, niobium, silicon,
manganese, steel or alloys or combinations thereof, and also oxides
of these metals, mixed with the binder, organic base material, and
water. Also, additional corrosion inhibitors or sintering aiding or
lubrication additives, generally in the range of 0.1-2 volume %,
can be added.
[0090] In another embodiment, the powder is instead a ceramic
powder such as silicon carbide, boron carbide, aluminum carbide,
tungsten carbide, titanium carbide, tantalum carbide, silicon
nitride, boron nitride, aluminum nitride, titanium nitride,
zirconium nitride, steatite, forsterite, alumina, zircon beryllia,
magnesia, mullite, cordierite, aluminum titanate and zirconia mixed
with the binder organic base material and water. Also additional
corrosion inhibitors, sintering aiding or lubrication additives,
generally in the range of 0.1-2 volume %, can be added.
[0091] In both these immediately foregoing embodiments, the binder
organic base material can be polyurethane, agar-agar, starch,
cellulosic materials, Agar (E406), Alginic acid (E400), Sodium
alginate (E401), Carrageenan (E407), Gum arabic (E414), Gum ghatti,
Gum tragacanth (E413), Karaya gum (E416), Guar gum (E412), Locust
bean gum (E410), Beta-glucan, Chicle gum, Dammar gum, Glucomannan
(E425), Mastic gum, Psyllium seed husks, Spruce gum, Tara gum
(E417), Gellan gum (E418), Xanthan gum (E415), polyethylene oxide,
polycarboxylic acids (polyacrylic acid), polycarboxylates,
polyvinyl alcohol, cellulose gum (Aquacel GSA and Aquacel GSH),
hydroxymethyl cellulose, hydroxypropyl cellulose, Carboxymethyl
cellulose, or combinations thereof.
[0092] Sintering aids such as salts, gum rosin or pine rosin,
isopropyl alcohol, propylene glycol, copper oxides, other metal
oxides, low melting point metals or alkaline earth metals can be
used. Lubricants aids such as essential oils, glycerin, zinc
stearate or other stearates, carbon black, silica and ferrous oxide
can be used. Corrosion inhibitors such as those selected from the
group consisting of nitrates of lithium, sodium, potassium,
calcium, magnesium, zinc, cobalt, iron, chromium, and copper, and
the nitrite of lithium, sodium, potassium, calcium, magnesium,
zinc, can be used.
[0093] With the compositions and processes of the present
invention, substantially all of the moisture, i.e. the water, and
other solvent or carrier components for the binder of the crafting
medium is removed immediately after deposition of each layer by use
of the drying means or apparatus. By "substantially all of the
moisture" is meant that at least about 90% by weight, and in
further embodiments at least about 95% by weight, and yet in
further embodiments at least about 99% by weight of the water and
other solvent or carrier components are removed. This novel method
of three-dimensional object building does not require the use of a
post-processing debinding step. Furthermore, the present invention
also provides a system for improved drying in a controlled manner
of a paste based crafting model during three-dimensional printing
and methods thereof. The drying means or apparatus can take the
forms described above. These means make drying possible after
printing each layer of the object (both mold and paste).
EXAMPLES
[0094] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-discussed embodiments may be used in combination with each
other. Many other embodiments will be apparent to those of skill in
the art upon reviewing the above description.
The benefits and advantages which may be provided by the present
invention have been described above with regard to specific
embodiments. These benefits and advantages, and any elements or
limitations that may cause them to occur or to become more
pronounced are not to be construed as critical, required, or
essential features of any or all of the embodiments.
[0095] While the present invention has been described with
reference to particular embodiments, it should be understood that
the embodiments are illustrative and that the scope of the
invention is not limited to these embodiments. Many variations,
modifications, additions and improvements to the embodiments
described above are possible. It is contemplated that these
variations, modifications, additions and improvements fall within
the scope of the invention.
EXAMPLES
[0096] The following examples further described and demonstrate
embodiments within the scope of the present invention. The Examples
are given solely for purpose of illustration and are not to be
construed as limitations of the present invention, as many
variations thereof are possible without departing from the spirit
and scope of the invention.
Example 1: Crafting Medium and Process for Making
[0097] A crafting medium comprising the following components was
prepared. The components are each on a volume % basis.
[0098] Stainless steel powder 17-4: 62%
[0099] Distilled water: 32%
[0100] Arrow root powder: 4%
[0101] Xanthan gum 1%
[0102] Polycarboxylate 1%
A premix of the water and arrow root powder is prepared by heated
to 80.degree. C. with stirring. The premix is then cooled to room
temperature. A separate premix of xanthan gum and the
polycarboxylate is made by combining them with stirring to form a
thick paste. Next, the stainless steel powder and the xanthan gum
premix are added to the arrow root premix and combined using a
mechanical stirrer.
[0103] The resulting paste is useful for three-dimensional
printing. The paste can be printed on a line-by-line and
layer-by-layer basis in conjunction with a mold layer. Each
deposited paste layer is dried according to the present invention.
The resulting three-dimensional object is then subsequently debound
and then sintered to provide the stainless steel three-dimensional
object.
[0104] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-discussed embodiments may be used in combination with each
other. Many other embodiments will be apparent to those of skill in
the art upon reviewing the above description.
[0105] The benefits and advantages which may be provided by the
present invention have been described above with regard to specific
embodiments. These benefits and advantages, and any elements or
limitations that may cause them to occur or to become more
pronounced are not to be construed as critical, required, or
essential features of any or all of the embodiments.
[0106] While the present invention has been described with
reference to particular embodiments, it should be understood that
the embodiments are illustrative and that the scope of the
invention is not limited to these embodiments. Many variations,
modifications, additions and improvements to the embodiments
described above are possible. It is contemplated that these
variations, modifications, additions and improvements fall within
the scope of the invention.
INCORPORATION BY REFERENCE
[0107] The entire disclosure of each of the patent documents,
including certificates of correction, patent application documents,
scientific articles, governmental reports, websites, and other
references referred to herein is incorporated by reference herein
in its entirety for all purposes. In case of a conflict in
terminology, the present specification controls.
EQUIVALENTS
[0108] The invention can be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The foregoing embodiments are to be considered in all
respects illustrative rather than limiting on the invention
described herein. In the various embodiments of the methods and
systems of the present invention, where the term comprises is used
with respect to the recited steps of the methods or components of
the compositions, it is also contemplated that the methods and
compositions consist essentially of, or consist of, the recited
steps or components. Furthermore, it should be understood that the
order of steps or order for performing certain actions is
immaterial so long as the invention remains operable. Moreover, two
or more steps or actions can be conducted simultaneously.
[0109] In the specification, the singular forms also include the
plural forms, unless the context clearly dictates otherwise. Unless
defined otherwise, all technical and scientific terms used herein
have the same meaning as commonly understood by one of ordinary
skill in the art to which this invention belongs. In the case of
conflict, the present specification will control.
[0110] Furthermore, it should be recognized that in certain
instances a composition can be described as being composed of the
components prior to mixing, or prior to a further processing step
such as drying, binder removal, heating, sintering, etc. It is
recognized that certain components can further react or be
transformed into new materials.
[0111] All percentages and ratios used herein are on a volume
(volume/volume) or weight (weight/weight) basis as shown, or
otherwise indicated.
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