U.S. patent application number 14/261320 was filed with the patent office on 2016-07-14 for cartridge-based 3d printing system.
The applicant listed for this patent is The Board of Regents of the University of Texas System, Syzygy Memory Plastics Corporation. Invention is credited to James Amato, Cary Baur, Wesley Fichera, Michael Moussa, Walter Voit.
Application Number | 20160200044 14/261320 |
Document ID | / |
Family ID | 51788599 |
Filed Date | 2016-07-14 |
United States Patent
Application |
20160200044 |
Kind Code |
A1 |
Voit; Walter ; et
al. |
July 14, 2016 |
CARTRIDGE-BASED 3D PRINTING SYSTEM
Abstract
Embodiments of the invention are directed to a 3D printing
system that directs projected light at tunable wavelengths to cure
a polymer resin from monomers or oligomers which floats on a dense
liquid platform in which the curing occurs within a prepackaged
vessel which facilitates the layer is printed at any given
time.
Inventors: |
Voit; Walter; (Dallas,
TX) ; Amato; James; (Dallas, TX) ; Fichera;
Wesley; (Burleson, TX) ; Moussa; Michael;
(Euless, TX) ; Baur; Cary; (Dallas, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Board of Regents of the University of Texas System
Syzygy Memory Plastics Corporation |
Austin
Dallas |
TX
TX |
US
US |
|
|
Family ID: |
51788599 |
Appl. No.: |
14/261320 |
Filed: |
April 24, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61815607 |
Apr 24, 2013 |
|
|
|
61815603 |
Apr 24, 2013 |
|
|
|
Current U.S.
Class: |
264/401 |
Current CPC
Class: |
B29C 64/268 20170801;
B23K 26/3576 20180801; B29C 33/3807 20130101; B29K 2105/0058
20130101; B33Y 80/00 20141201; B29K 2105/12 20130101; B23K 2103/42
20180801; B29C 64/20 20170801; B29C 33/40 20130101; A61F 2240/004
20130101; B29K 2105/0032 20130101; B33Y 99/00 20141201; B33Y 10/00
20141201; B29C 64/135 20170801; B23K 2103/50 20180801; B29K
2105/0044 20130101; B29K 2105/0002 20130101; H04R 25/652 20130101;
B33Y 30/00 20141201; B29C 45/00 20130101; B29L 2031/7532 20130101;
B29K 2105/0005 20130101 |
International
Class: |
B29C 67/00 20060101
B29C067/00 |
Claims
1. A 3D printing system comprising: a light source; at least one
cartridge casing, wherein the casing comprises a fill port; and a
resin that floats on a liquid platform.
2. The system of claim 1, wherein the resin is located within the
cartridge casing.
3. The system of claim 1, wherein the resin is cured by projecting
the light source on the resin inside of one or more cartridge
casings.
4. The system of claim 1, wherein the light source can be of a
single wavelength, tuned to different wavelengths, or be a spectrum
of wavelengths.
5. The system of claim 1, wherein the light source has one or more
wavelengths ranging from 10 nm to 800 nm.
6. The system of claim 1, wherein the light source is selected from
one or a combination of light emitting diodes, organic light
emitting diodes, lasers, excimer lamps, mercury arc lamps, metal
halide lamps, fluorescent lights, focused or directed solar
radiation, gas-discharge lamps or incandescent lamps.
7. The system of claim 1, wherein the light source is focused,
redirected or positioned through digital mirror displays or shadow
masks to control the image that is projected onto the resin.
8. The system of claim 1, wherein the resin can be made from a
variety of monomers and oligomers including, but not limited to
acrylates, urethanes, thiols, alkenes, vinyls, styrenics, acetates,
fluorinated monomers, isocyanates, ureas, silicones, and epoxides
and combinations of these materials.
9. The system of claim 8, wherein the resin comprises additives
such as a photoinitiator, reaction inhibitors, reactive or
non-reactive diluents, colorants for aesthetic or functional
purposes, antimicrobial particles such as silver micro or
nanoparticles, short fiber filler for added toughness, UV
absorbers, UV blockers, radical scavengers, or other fillers.
10. The system of claim 1, wherein the liquid platform is comprised
of a base fluid and optional additives, such as, but not limited
to, sugar, salt, starch, ions, proteins, or combinations thereof,
such that the Z-fluid is more dense than the resin.
11. The system of claim 1, wherein the system comprises more than
one cartridge casing.
12. A process of 3D printing using the system of claim 1, the
process comprising the steps of: introducing the liquid platform
into the cartridge casing through the fill port; allowing the resin
the flow over a printed part or build table; manipulating the
liquid platform from the cartridge casing to allow the resin to
settle over the printed part or build table; and curing the resin
by projecting the light source on the resin.
13. The process of claim 12, wherein the liquid platform and/or
resin are agitated, shaken, vibrated or otherwise moved through
piezoelectric, ultrasonic or other mechanical means.
14. The process of claim 12, wherein the height of the liquid
platform is controlled vertically in order to control the thickness
of the resin.
15. The process of claim 12, wherein the curing occurs when the
projected light stimulates the resin and triggers a polymerization
reaction of the portion of the resin upon which the light is
projected.
16. The process of claim 12, wherein the resin is packaged within
the cartridge casing and optionally pre-packaged with functional
components such as but not limited to electronic chips, audio
drivers, structural supports, tubes, hoses, wires or other
components which the resin will ultimately be printed on, in or
around.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C.
.sctn.119(e) of U.S. Provisional Patent Application No. 61/815,603
filed Apr. 24, 2013, and U.S. Provisional Patent Application No.
61/815,607 filed Apr. 24, 2013 which are incorporated herein by
reference in its entirety as if fully set forth herein.
FIELD OF THE INVENTION
[0002] Embodiments of the invention are directed to systems,
apparatuses and business models for rapidly building custom
products out of polymers using 3D printing systems.
BACKGROUND OF THE INVENTION
[0003] 3D printing or additive manufacturing is a process of making
a three-dimensional solid object of virtually any shape from a
digital model. 3D printing is achieved using an additive process,
where successive layers of material are laid down in different
shapes. 3D printing is also considered distinct from traditional
machining techniques, which mostly rely on the removal of material
by methods such as cutting or drilling (subtractive processes).
[0004] A 3D printer is a limited type of industrial robot that is
capable of carrying out an additive process under computer
control.
[0005] The 3D printing technology is used for both prototyping and
distributed manufacturing with applications in architecture,
construction, industrial design, automotive, aerospace, military,
engineering, dental and medical industries, biotech (human tissue
replacement), fashion, footwear, jewelry, eyewear, education,
geographic information systems, food, and many other fields.
[0006] In light of the multiple uses that 3D printing lends itself
to, it would be beneficial to use some of the advantages of this
technique to build custom product using a variety of materials.
SUMMARY OF THE INVENTION
[0007] An embodiment of the invention is directed to a 3D printing
system that directs projected light at tunable wavelengths to cure
a polymer resin from monomers or oligomers that is floating on a
more dense liquid platform, wherein the curing occurs within a
prepackaged vessel that facilitates the printing of specific layers
are any given time.
[0008] Embodiments of the claimed invention are directed toward
improve existing 3D printed parts by innovating on the interaction
between polymerization of the resin and the 3D printer inside of
cartridges. For the system described herein, prints occur inside of
a cartridge which improves upon a number of issues with existing
printers.
[0009] There are two different classes of 3D printers based on
cost. There are currently high cost printers, beginning at $10,000
and running into the millions of dollars; and there are hobbyist 3D
printers, ranging in price from $100 to $10,000. The latter are
usually based on open source kits and have widely varying degrees
of accuracy and repeatability. Depending on the market application,
the tradeoff among price and various technical properties including
material properties, print speed, print resolution, etc. can be
important.
[0010] Another way of organizing these printers is by feed stock,
of which there are four categories. The first of these is the
powdered, sinter-able material used in Selective Laser Sintering
(SLS) machines--all of which are currently very high in cost. The
second is the thermoplastic filament of fused filament fabrication
(FFF) machines. These printers tend to have a fairly proportional
cost vs quality curve--e.g. low cost printers tend to be of poor
resolution and variable build quality. The third is akin to inkjet
printing in which a thin layer of monomer is deposited on a surface
and cured by UV, optical light, laser or other sources. The fourth
of these are thermoset resin based SLA printers, available at all
range of costs.
[0011] One issue with SLA printers in general is that many resins
are not safe to handle or are environmentally harmful, thus
requiring special handling. To date, this means that only companies
with trained professionals or very interested hobbyists are willing
to take the risk associated with exposure to the resins.
Furthermore, those systems require purge cycling to clean out
printer components, such as vats, feed lines, vessels or other such
areas which interface with resin between materials changes. This is
quite wasteful, and coupled with the generally high cost of resins,
this typically precludes the adoption at home of generalized
resins. Companies face issues in shelf life of resins, especially
after they have been "opened." There does not exist the ability to
easily and rapidly change materials between print jobs. There is no
simple way to print multiple materials at once on the same
printer.
[0012] The system described uses a cartridge-based system to get
around these issues. Because the resin is packaged and contained
within a pre-sealed cartridge, when used properly, there will be no
exposure to uncured resin. The system uses a so-called `z-fluid` to
control height and move the resin relative to the build table
inside, allowing clean, efficient prints. This means that the
machine will not be exposed to resin and thus never be subject to
purge cycles. There are other innovations that readily follow, such
as the printing of multiple parts at the same time using different
resins. A further advantage is the limited stock required for
purchase. Currently, materials are usually sold in large quantities
at fairly high prices. This system would enable sale of much
smaller amounts of resin in a single batch, also eliminating waste.
These lower volumes of stock would also amount to a larger variety
of stock.
[0013] Cartridges that are sealed and packaged with the resin can
be bought and sold individually following a business models similar
to the Keurig K-cup model in which users and customers buy
cartridges that fit into a system. The processing occurs in a
standardized disposable (or refillable) container in which the
contents are variable and chosen by the user. Attachments for the
system can allow advanced users self-filling capabilities. This
limits cleaning, waste of the resin, purging steps, and allows 24/7
use of the equipment to select rapidly from among different color
parts, and parts made from different materials.
[0014] The self-contained nature of this system allows for ease in
the supply chain and distribution and facilitated standardized
packaging in large scale manufacturing facilities. Due to the scale
of this system, extremely low cost cartridge packaging can be
amortized over large numbers of cartridges. This allows for the
potential to produce the system at a very competitive price point
to encourage system use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 sets forth the printer terminology in accordance with
an embodiment of the invention;
[0016] FIG. 2 depicts a cartridge's life cycle in accordance with
an embodiment of the invention;
[0017] FIGS. 3A to 3D depicts the structure and design of the
cartridge's fill ports in accordance with embodiments of the
invention;
[0018] FIG. 4 depicts the specific layer printing steps in
accordance with an embodiment of the invention;
[0019] FIGS. 5A to 5C shows a top layer refresh in accordance with
an embodiment of the invention;
[0020] FIG. 6 shows image size and focus as a function of projected
distance in accordance with an embodiment of the claimed
invention;
[0021] FIGS. 7A to 7C shows the changing of the projected distance
with a layer refresh in accordance with an embodiment of the
invention;
[0022] FIGS. 8A to 8C shows the fixed ("F") cartridge system in
accordance with an embodiment of the invention;
[0023] FIGS. 9A to 9C shows the Z-cartridge system in accordance
with an embodiment of the invention;
[0024] FIGS. 10A to 10C shows the sinking ("S") cartridge system in
accordance with an embodiment of the invention;
[0025] FIGS. 11A to 11E shows a process for passively adjusting
build height in accordance with an embodiment of the invention;
[0026] FIGS. 12A and 12B shows the image size and focus as a
function of projected distance in accordance with an embodiment of
the invention;
[0027] FIGS. 13A to 13C shows the orientation of projector and
light guides in accordance with embodiments of the invention;
and
[0028] FIGS. 14A to 14C shows the use of a single projector for
multiple concurrent prints.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0029] An embodiment of the claimed invention is directed to a 3D
printing system ("system"). The system directs projected light at
tunable wavelengths ("light source") to cure a polymer resin from
monomers or oligomers ("resin") which is floating on a higher
density liquid platform ("Z-fluid") in which the curing
("reaction") occurs within a prepackaged vessel ("cartridge") which
facilitates the layer which is printed at any given time. In a
further embodiment, the resin can be packaged, sealed and sold
within the cartridge. Cartridges of different sizes and dimensions
contain different amounts of different colored materials. This
allows users to rapidly select from among many combinations when
ordering cartridges and easily switch materials, colors, sizes
between successive print jobs without a costly system wide resin
purge. One or more cartridges are loaded into the system, which
allows for quick and convenient Z-fluid manipulation and the
printing of the part within the cartridge. To our knowledge, no
printer prints parts inside the cartridge which contains the resin.
All other systems remove resin from some temporary storage tank and
relocate it to a print area. This innovation spawns a host of new
business models, new ways to handle resin and new ways to interact
with more complex pre-polymers. The system allows for the
simultaneous printing of different materials, different parts,
different resolutions and different colors. In one embodiment, up
to 100 different custom components can be printed at the same time
having varying properties such as colors and made from different
modulus materials or varying chemical composition.
[0030] In accordance with an embodiment of the invention, the light
source can be at a uniform, single wavelength or combinations of
wavelengths in the extreme UV range (below about 120 nm), vacuum UV
(from about 10 to about 200 nm), UVC (about 200 to about 280 nm,
including low pressure mercury lamp sources near 254 nm), UVB
(about 280 to about 320 nm), UVA (about 320 to about 400 nm,
including high pressure mercury lamps or metal halides near 365
nm), within the visible spectrum (about 400 nm to about 800 nm) or
within the IR spectrum and beyond (above 800 nm). The choice of the
light source is dependent upon its ability to directly or
indirectly lead to curing (reaction). The light source is not
limited to, but typically chosen from among one or a combination of
light emitting diodes, organic light emitting diodes, lasers
(particularly systems which allow for infinite focus projection),
excimer lamps, mercury arc lamps, metal halide lamps, fluorescent
lights such as black lamps, focused or directed solar radiation,
gas-discharge lamps or incandescent lamps. In an embodiment of the
claimed invention, the light source is a commercially available
home theater projector using Texas Instruments DLP Technology or
other forms of digital light projection based photo-curing. In
another embodiment, the light source is a commercially available
Red, Blue and Green Laser light source.
[0031] In accordance with claimed embodiments of the invention, the
resin can be made from a variety of monomers and oligomers
including, but not limited to acrylates, urethanes, thiols,
alkenes, vinyls, styrenics, acetates, isocyanates, ureas,
fluorinated monomers, silicones, and epoxides and combinations of
these materials. The resin optionally contains additives including
but not limited to a photoinitiator which is dictated by the chosen
wavelength of light, light absorbers which limit the depth of cure
through the resin, reaction inhibitors which control the kinetics
of the reaction, reactive or non-reactive diluents which help
control the viscosity of the resin, colorants for aesthetic or
functional purposes, antimicrobial particles such as silver micro
or nanoparticles, short fiber filler for added toughness, and other
fillers to create composite structures from The Resin. In an
embodiment, the photoinitiator is bis-acyl phosphine oxide (BAPO).
In another embodiment the photoinitiator is
2,2-dimethoxy-2-phenylacetophenone (DMPA). In another embodiment
the photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine
oxide (TPO). In another embodiment the photoinitiator is chosen
from within the family of Irgacure and Darocure initiators (from
BASF).
[0032] In accordance with embodiments of the invention, the Z-fluid
refers to a system which is comprised of a base fluid (such as
distilled deionized water, tap water, corn syrup, brine, sugar
water, liquid metals such as mercury, eutectic gallium indium,
various gallium alloys, ferrofluid or other fluid media) and
optional additives, such as, but not limited to, sugar, salt,
starch, ions, proteins, or combinations thereof, such that the
Z-fluid is more dense than the resin. In one embodiment, the
Z-fluid can be actively manipulated (through pumping, partial
pressures, or mechanical compression) to control the height of the
top level of the resin which floats on the Z-fluid within the
cartridge. In another embodiment, the cartridge is manipulated
(mechanically or otherwise) relative to an external (perhaps
secondary) Z-fluid bath. The height of the Z-fluid plus the resin
is typically maintained at the focal plane of the projected image
or at such as height (in situations of infinite focus laser
projections) such that the projected image or trace is of desired
size (see FIG. 7). The Z-fluid height is manipulated up and down in
a process called "surface refreshing" such that a controlled
thickness of resin is above the growing printed part (see FIG. 6).
Part of the resin is cured into the growing part, which is
progressively submerged under the remaining resin and the Z-fluid
as successive layers are printed on the top surface (see FIG. 5).
The printed part ends up under the Z-fluid. In an embodiment of the
claimed invention that utilizes water and additives such as sugar,
the part ends up underwater when the print is completed (see FIG.
4D). The flow rate of the Z-fluid dictates both the accuracy of the
print and the speed of the print. In one embodiment that has been
reduced to practice the Z-fluid has been able to be manipulated
with greater than 10 micron precision. In one embodiment reduced to
practice the Z-fluid has been able to be manipulated at greater
than 350 mL/min in a Cartridge with a volume of about 240 cubic
centimeters. Larger Cartridges and/or larger, more sophisticated
Z-fluid manipulators could increase this flow rate
substantially.
[0033] In accordance with embodiments of the claimed invention, the
reaction occurs when the projected light stimulates the resin and
triggers a polymerization reaction of the portion of the resin upon
which the light is projected. The kinetics of the reaction and the
amount of the resin that cures in each successive printing step are
controlled through choice of light source, light duty cycle, light
intensity, pattern of the image on the surface of the resin and the
photo-sensitive portion of the resin. The depth of cure of the
resin during the reaction is a product of the interaction of these
parameters and the height of the surface refreshing step. The
viscosity of the resin as it refreshes over the part during Z-fluid
manipulation influences the speed with which iterative print steps
can be undertaken. In one embodiment, the reaction can progress in
a continuous manner as the Z-fluid is manipulated. In other
embodiments, the reaction is punctuated by the changing the image
and wavelengths of light on the surface of the resin. In one
embodiment, the surface refreshing step is sped up to less than six
seconds such that the final part print time occurs within 20
minutes. In another embodiment the surface refreshing step occurs
at a speedy rate such that the system appears to be printing
continuously.
[0034] In accordance with an embodiment, a revolutionary aspect of
the claimed invention is the manner in which the cartridge
interacts with the 3D printing system.
[0035] In an embodiment, the resin can be packaged, sealed and sold
within the cartridge. Cartridges of different sizes and dimensions
contain different amounts of different colored different materials.
This allows users to rapidly select from among different
combinations when ordering the cartridges and easily switch
materials, colors, sizes between successive print jobs without a
costly system wide resin purge.
[0036] In an embodiment, the cartridge can interact with the 3D
printing system in a way that allows the cartridge to be shaken,
twisted, spun, or vibrated in an effort to help control resin
settling at increasing small layer thicknesses. For example, this
could use piezoelectric or ultrasonic methods to controllably
agitate the cartridge. Many designs can be envisioned toward this
end and would be obvious extensions of the claimed invention to one
skilled in the art.
[0037] In certain embodiments, one or more cartridges are loaded
into the system, which allows for quick and convenient Z-fluid
manipulation and the printing of the part within the cartridge(s).
The system would allow for the simultaneous printing of different
materials, different parts, different resolutions and different
colors. In an embodiment, it is possible to print up to 100
different custom earpieces at the same time in different colors and
made from slightly different modulus materials using this system
(see FIG. 2).
[0038] In an embodiment, the cartridge is comprised of "the
casing," "the lid," "the build table," "the fill port(s)" and
optionally other interfaces for post processing steps.
[0039] In an embodiment, the cartridge also serves as the final
packing material for the sale of a part. For example, a user could
enter a brick and mortar store, have a scan made of their ear
canal, choose a material stiffness and aesthetics (color, sparkles,
texture, etc.). The part would print in real time in front of the
user inside the cartridge, which could optionally also serve as the
labeled packaging for the produced good.
[0040] In an embodiment, the cartridge contains interfaces such as
inlets for compressed air, supercritical carbon dioxide or other
methods to control the porosity or density of either the resin of
the polymer as it cures. This can be very useful for the printing
of foam-like structures or structures with pseudo-random porosity
below or above the print resolution.
[0041] In an embodiment, the cartridge may contain a predetermined
structure within the cartridge suspended above the resin and well
encapsulated. For example a computer chip, an electronics housing
necessary to drive speakers, a preassembled earphone, hearing aid,
Bluetooth device or other audio component could be preassembled,
packaged into the cartridge and packaged with a specific resin
composition. Users or businesses could use these pre-fabricated
units and print custom earpieces for users on the spot after which
a functional post-processing step could enable sophisticated
functionality. Other such models in which components are
pre-packaged within the cartridge can be likewise envisioned and
audio products merely serve as one example and not an exhaustive
list of pre-packaged applications.
[0042] In an embodiment, the light source can project images at
non-active wavelengths (in the visible spectrum) superimposed on
the print surface such that targeted commercial advertising occurs
on the surface as the print is taking place. Since watching these
prints is a novelty (for now at least), there is a captive audience
and target eyeballs and prime real estate for branding high tech
products and technologies. Alternatively, an episodic series of
short perhaps funny or clever skits or animations could help
incentivize and reward use.
[0043] The composition of the cartridge can be made out of
materials such that the resin can be easily removed from it.
Potential materials include fluorinated plastics (teflon/ptfe),
polypropylene, polyethylene, polyoxymethylene, texin, and a variety
of others. The cartridge may be injection molded, blow molded,
vacuum-assisted resin transfer molded, extruded and shaped,
otherwise thermoplastically processed or assembled from individual
sheets with adhesive or welding techniques. The cartridge may
optionally be fabricated partially or wholly from composite
materials, thermoset materials, metals or in rare cases
ceramics.
[0044] The composition of the cartridge can be made of materials
such that the cartridge is recyclable, within a single or multiple
recycling streams. The cartridge may be partially or wholly made
out of materials that dissolve or degrade upon exposure to specific
stimuli, such as but not limited to heat above a certain
temperature, exposure to acids or bases, exposure to solvents or
exposure to radiation in the form of the energetic photons.
[0045] In an embodiment, the cartridge is an injection molded part
that is filled with the resin and vacuum sealed during
manufacturing. The vacuum sealing process occurs such that the
sealing material is a film transparent to the light source and
resistant to the resin over the specified shelf life of the
cartridge.
[0046] There are several different mechanisms as to how z-fluid can
be introduced into the cartridge and manipulated while within the
cartridge. In all cases, it is important to prevent resin from
exiting the cartridge during the print job. In one embodiment, the
cartridge is screwed into place, and this action reveals holes in
the bottom of the cartridge through which z-fluid can rise. In
another embodiment, the cartridge snaps into place, and syringe
needles perforate a foil seal. In this embodiment, the bevel on the
needles matches in length to the wall thickness of the cartridge.
In another embodiment, the cartridge is divided such that the two
sides of the cartridge are separated only via a small hole located
in the bottom; fluid is introduced in a side without resin to
prevent resin from escaping.
[0047] Fluid may be introduced actively or passively. In active
systems, Z-fluid is pushed with a pump, usually a syringe or
peristaltic pump, but also optionally one of a variety of other
types of pumps (see FIG. 8). Additionally, raising or lowering
fluid pressure may be accomplished by manipulating partial pressure
or air or another fluid, either pulling vacuum where it is intended
to rise, or raising pressure where it is intended to fall.
Moreover, in a passive system, the cartridge itself would rise or
fall and fluid would flow into or out of that cartridge.
[0048] The cartridge system also opens the possibility for
interesting business models. In many, a focus on sustainability is
made possible. In one such embodiment, the cartridges are preloaded
into a vending machine for a specific customized product. The
machine is able to print and remove the part, then any extra resin
remains in the cartridge and the cartridge remains in the machine.
The used cartridges can then be picked up for proper recycling and
reuse. This scenario is in opposition to a system wherein a part is
printed in a machine and remaining resin must be flushed or
polymerized in order to change colors.
[0049] In another embodiment, the cartridges are prefilled with
specific masses of resin, so that a part printed within such the
cartridge does not leave residual resin. In a similar embodiment, a
facility could be set up where the cartridges are filled to order.
This allows end users to select from a wider variety of sizes,
materials, and colors, while the inventory is stored in more
discretized units.
[0050] There are several different mechanisms by which the print is
anchored within the cartridge.
[0051] Two issues that can arise from the distance between the
light source and the height of the resin within the cartridge are
(i) the focus of the projected light and (ii) the size of the
image. The focus of the light can be adjusted or accounted for in
several ways including, but not limited to using an infinite focus
laser projector, moving the projector to match the height change of
the resin when the cartridge is stationary or moving the cartridge
to keep the top surface of the resin within the focal plane of the
light source. Alternatively in designs of the cartridge in which
the cartridge is porous and interacts with an external z-fluid, the
light source and the cartridge could move in tandem relative to the
z-fluid as the part is printed.
[0052] Embodiments of the claimed invention are directed to several
distinct types of cartridges. A cartridge may be picked depending
upon the proposed use. The claimed invention allows for variable
actuation mechanisms which describe how the distance between the
top of the resin and the light source are manipulated.
[0053] F-cartridges: In one embodiment, fixed cartridges called
"f-cartridges" are used in which the cartridge is actively filled.
The light source moves on the z-axis. The Z-fluid is actively
pumped or otherwise manipulated in the z-direction. The cartridge
remains fixed on the z-axis. The f-cartridge based system is
depicted in FIG. 9.
[0054] Z-cartridges: In another embodiment, z-axis mobile
cartridges called "Z-cartridges" are used in which the cartridge is
also actively filled. The cartridge moves along the z-axis to
compensate for fluid being pumped or otherwise manipulated. The
light source is fixed. A z-cartridge based system is depicted in
FIG. 10.
[0055] S-cartridges: In yet another embodiment, sinking cartridges
called "s-cartridges" are used in which the cartridge is porous
upon "cartridge activation" such that z-fluid can flow in and out
of the cartridge while the resin remains within the cartridges. For
example, this is a porous cartridge in which the cartridge moves
within the z-fluid while the distance of the light source to top
surface of the resin remains unchanged. Specific examples would be
printing something in a fixed basin, in a kitchen sink, in a
bathtub, in a swimming pool in a pond, in a lake or in an ocean.
The z-axis motor or hydraulic pump or other means of cartridge
manipulation allows the cartridge to be submerged into the z-fluid
during the print process. An embodiment of the S-cartridge system
is depicted in FIG. 11.
[0056] In an embodiment, the printer is compatible with a
multi-cartridge system is compatible with all three types of
cartridges, f, z and s series. For simplicity this system is shown
in the z series in the attached figures, but can be readily made
with multiple cartridges in each system.
[0057] In embodiments of the claimed invention, the light source
can be stationary or mobile. In embodiments of the invention,
multiple cartridges can be included. The number of cartridges can
be but are not limited to 4, 16, 25 and 100 cartridges. Most often,
multi-cartridge prints are useful when a standard part or several
parts needs to be printed in different colors out of different
materials. The simultaneous nature of a multi-cartridge system
allows this scenario in rapid time.
[0058] In embodiments of the claimed invention, the z-fluid can
globally fill all cartridges at one uniform rate or individually
fill cartridges at different rates.
[0059] In yet another embodiment of the claimed invention, the
z-fluid can be a series of macro, micro or nanoparticles or objects
that can be filled into the cartridge to displace resin and
manipulate the height of the resin. While this may seem impractical
in many but a few specialty cases, this method of manipulating
resin height through filling and removing of solid particles can be
necessary to limit interaction with certain resins with other
fluids. In one specific embodiment, small BB pellets can be fed
into a cartridge to alter the build height.
[0060] In yet other embodiments, solid objects could be added into
a system that is partially filled with other z-fluid which can
limit the size of the pump and z-fluid reservoir needed for larger
or more complex prints.
[0061] The accompanying drawings illustrate several aspects of the
claimed invention. FIG. 1 depicts (A) the projector, (B) the
maximum area ("build envelope") of the projected image, (C) an
example projected image where resin cure will actually take place,
(D) the resin, (E) the printed part, (F) the Z-fluid, (G) the build
table, (H) the cartridge casing, (I) the cartridge lid, and (J) a
typical fill port
[0062] FIG. 2 depicts (A) the cartridge as manufactured without lid
attached ready to be filled, (B) the cartridge ready for sale and
use, filled with a pre-selected amount of resin, (C) the cartridge
after loading into the machine, filled with a small amount of
Z-fluid, just enough to raise the top surface of the resin to the
height for the first printing layer, (D) the cartridge at the end
of printing, containing a printed part completely covered by
z-fluid with a minimal amount of residual resin on the top surface,
(E) the cartridge as removed from the printer, containing no
Z-fluid and only a printed part and thin cured layer of resin at
the top
[0063] FIG. 3 depicts various arrangements of fill ports and
compatible build table designs. When fluid is actively pumped
directly into the cartridge, it must be done through a port and is
thus practically limited. When fluid is not pumped directly into
the cartridge, many more apertures, or even a mesh, can be used.
This also applies when the cartridge is moved as in the S-Cartridge
system.
[0064] FIG. 4 depicts the sequence of printing steps, comprising
(A) the previous layer complete, (B) the Z-fluid added to the
cartridge in a sufficient quantity that the resin completely flows
over the top surface of the part, (C) the z-fluid removed from the
cartridge such that the resin has settled to exactly one print
level thick, (D) the active curing image projected onto the part,
selectively curing the layer, (E) the layer has cured and bonded to
the rest of the printed part and the curing image is no longer
displayed
[0065] FIG. 5 shows the top layer refresh consists of the z-fluid
rising enough that resin completely covers the printed part, then
the z-fluid falling to a level where the resin will settle exactly
one layer-thickness above the printed part.
[0066] FIG. 6 illustrates a target distance, at which the image is
in focus and of the correct size, as well as closer and further
from that target distance such that the image is out of focus
(blurry) and either undersized (too close) or oversized (too far
from the projector).
[0067] FIG. 7 illustrates that as the printing proceeds, each
printed layer is at a different distance from the projector, and
thus some active mechanism is needed in order to counter that and
keep the image the correct size and in focus.
[0068] FIG. 8 shows that in the fixed cartridge system, as z-fluid
is pumped into a fixed cartridge to raise the print level, the
projector is raised to keep the focal plane at the resin
surface.
[0069] FIG. 9 shows that in the z-cartridge system, as z-fluid is
pumped into the cartridge to raise the print level, the cartridge
is lowered to keep the focal plane at the resin surface.
[0070] FIG. 10 shows that in the sinking cartridge system, the
cartridge is lowered into a bath of z-fluid to raise the print
level and there is no change in the distance between the projector
and the surface of the resin.
[0071] FIG. 11 shows one of the passive aspects of the system which
is the use of relative pressure to manipulate the level of resin
without actively pumping z-fluid.
[0072] FIG. 12 shows that in a standard projector, there exists a
focal plane outside of which the image is blurred. In an infinite
focus projector, however, the image is always in focus. In both
cases, the size of the image varies with distance and so must be
accounted for.
[0073] FIG. 13 shows that the projector may be positioned in a
variety of orientations and the image manipulated using mirrors. In
this way, the size of the system is variable.
[0074] FIG. 14 shows that a single projector can print multiple
parts using only a section of the available area for each part. At
the very least, this allows multiple materials to be printed using
separate vats. Ideally, each vat would be independently controlled
and parts can be started at different times. In such a system, the
position of the cartridge would need to be actively controlled.
[0075] While particular embodiments of the present disclosure have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
disclosure. It is therefore intended to cover in the appended
claims all such changes and modifications that are with the scope
of this disclosure.
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