U.S. patent application number 15/807220 was filed with the patent office on 2018-10-04 for three dimensional printing system that automatically removes particles from build plane.
The applicant listed for this patent is 3D Systems, Inc.. Invention is credited to Andrew Enslow, Martin Alan Johnson, Robert Mueller, James Pingel, Christopher Tanner, Ben Wynne.
Application Number | 20180281287 15/807220 |
Document ID | / |
Family ID | 60451189 |
Filed Date | 2018-10-04 |
United States Patent
Application |
20180281287 |
Kind Code |
A1 |
Tanner; Christopher ; et
al. |
October 4, 2018 |
THREE DIMENSIONAL PRINTING SYSTEM THAT AUTOMATICALLY REMOVES
PARTICLES FROM BUILD PLANE
Abstract
A three dimensional printing system includes a print engine, a
fixture, and a controller. The print engine further includes a
vessel, a light engine, and a movement mechanism. The vessel is for
containing a photocurable resin and has a lower portion with a
transparent sheet defining a lower surface of the vessel. The light
engine is configured to project radiation up through the
transparent sheet over a lateral build plane which defines a
maximum addressable lateral range of the light engine. The fixture
has a lower face that faces downwardly. The controller is
configured to: (1) position the lower face of the fixture at the
build plane, and (2) operate the light engine and movement
mechanism to solidify a particle trapping sheet proximate to the
transparent sheet and substantially spanning the build plane and to
thereby trap particles that are present along the build plane.
Inventors: |
Tanner; Christopher; (San
Diego, CA) ; Enslow; Andrew; (Escondido, CA) ;
Wynne; Ben; (Escondido, CA) ; Mueller; Robert;
(San Diego, CA) ; Pingel; James; (San Diego,
CA) ; Johnson; Martin Alan; (Rock Hill, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3D Systems, Inc. |
Rock Hill |
SC |
US |
|
|
Family ID: |
60451189 |
Appl. No.: |
15/807220 |
Filed: |
November 8, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62477747 |
Mar 28, 2017 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B33Y 50/02 20141201;
B29C 64/40 20170801; B29C 64/20 20170801; B29C 64/124 20170801;
B29C 64/393 20170801; B29C 64/245 20170801; B29C 64/153 20170801;
B29C 64/35 20170801; B33Y 30/00 20141201; B29C 64/227 20170801;
B33Y 10/00 20141201; B29C 64/129 20170801 |
International
Class: |
B29C 64/393 20060101
B29C064/393; B29C 64/245 20060101 B29C064/245; B29C 64/227 20060101
B29C064/227; B29C 64/40 20060101 B29C064/40; B29C 64/153 20060101
B29C064/153 |
Claims
1. A three dimensional printing system comprising: a print engine
including: a vessel for containing a photocurable resin and having
a lower portion with a transparent sheet; a light engine configured
to project radiation up through the transparent sheet over a build
plane defining a maximum addressable lateral range of the light
engine; and a movement mechanism; and a fixture coupled to the
movement mechanism with a lower face; and a controller configured
to: (1) position the lower face of the fixture at an operating
distance from the transparent sheet; and (2) operate the light
engine and movement mechanism to solidify a particle trapping sheet
proximate to the transparent sheet and substantially spanning the
build plane and to thereby trap particles that are present along
the build plane.
2. The three dimensional printing system of claim 1 wherein a lower
end of the fixture defines a recessed surface and a plurality of
projections extending downwardly from the recessed surface to
distal tips, the particle trapping sheet is formed onto the distal
tips.
3. The three dimensional printing system of claim 2 wherein the
particle trapping sheet includes an upper surface coupled to the
distal tips and an opposed lower surface, the controller is further
configured to operate the light engine and movement mechanism to
form a three dimensional article of manufacture onto the opposed
lower surface.
4. The three dimensional printing system of claim 3 wherein the
opposed lower surface includes a plurality of tapering features
that couple the three dimensional article of manufacture to the
opposed lower surface whereby the three dimensional article of
manufacture can be separated from the tapering features along a
minimal surface area.
5. The three dimensional printing system of claim 2 wherein the
printing system includes a transport mechanism and the controller
is further configured to: (3) unload the fixture from the print
engine; (4) load a new fixture into the printing system; and (5)
operate the light engine and the movement mechanism to form a three
dimensional article of manufacture.
6. The three dimensional printing system of claim 1 wherein the
controller is configured to operate the light engine and the
movement mechanism to form a three dimensional article of
manufacture between step (1) and step (2).
7. The three dimensional printing system of claim 6 wherein the
particle trapping sheet includes a plurality of upwardly extending
extensions that form a framework for supporting the particle
trapping sheet onto the three dimensional article of
manufacture.
8. The three dimensional printing system of claim 1 wherein the
particle trapping sheet includes at least one opening passing from
an upper surface to an opposed lower surface to provide flow of
photocurable resin therethrough when the movement mechanism is
raising or lowering the fixture.
9. The three dimensional printing system of claim 1 wherein the
particle trapping sheet includes a thin parallelepiped portion
covering most of the lateral area of the build plane, the particle
trapping sheet includes a framework of ribs that provide mechanical
support for the thinner portion.
10. A method of operating a three dimensional printing system for
forming a three dimensional article of manufacture, the three
dimensional printing system including a resin vessel containing
photocurable resin and having a lower portion with a transparent
sheet, a light engine configured to project radiation up through
the transparent sheet over a build plane defining a maximum
addressable lateral range of the light engine, a movement
mechanism, a fixture coupled to the movement mechanism with a lower
face, and a controller, the method including: (1) positioning the
lower face of the fixture at an operating distance from the
transparent sheet; and (2) operating the light engine and movement
mechanism to solidify a particle trapping sheet proximate to the
transparent sheet and substantially spanning the build plane to
thereby trap particles that are present along the build plane.
11. The method of claim 10 wherein a lower end of the fixture
defines a recessed surface and a plurality of projections extending
downwardly from the recessed surface to distal tips and the
particle trapping sheet is formed onto the distal tips.
12. The method of claim 11 wherein the particle trapping sheet
includes an upper surface coupled to the distal tips and an opposed
lower surface, the method further comprising operating the light
engine and movement mechanism to form a three dimensional article
of manufacture onto the opposed lower surface.
13. The method of claim 12 wherein the opposed lower surface
includes a plurality of tapering features that couple the three
dimensional article of manufacture to the opposed lower surface
whereby the three dimensional article of manufacture can be
separated from the tapering features along a minimal surface
area.
14. The method of claim 11 wherein the printing system includes a
transport mechanism and the method further comprises: (3) unload
the fixture from the print engine; (4) load a new fixture into the
printing system; and (5) operate the light engine and the movement
mechanism to form a three dimensional article of manufacture.
15. The method of claim 10 further comprising operating the light
engine and the movement mechanism to form a three dimensional
article of manufacture between step (1) and step (2).
16. The method of claim 15 wherein the particle trapping sheet
includes a plurality of upwardly extending extensions that form a
framework for supporting the particle trapping sheet onto the three
dimensional article of manufacture.
17. The method of claim 10 wherein the particle trapping sheet
includes at least one opening passing from an upper surface to an
opposed lower surface to provide flow of photocurable resin
therethrough when the movement mechanism is raising or lowering the
fixture.
18. The method of claim 10 wherein the particle trapping sheet
includes a thin parallelepiped portion covering most of the lateral
area of the build plane, the particle trapping sheet includes a
framework of ribs that provide mechanical support for the thinner
portion.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This non-provisional patent application claims priority to
U.S. Provisional Application Ser. No. 62/247,747, Entitled "THREE
DIMENSIONAL PRINTING SYSTEM THAT AUTOMATICALLY REMOVES PARTICLES
FROM BUILD PLANE" by Christopher Tanner et al., filed on Mar. 28,
2017, incorporated herein by reference under the benefit of U.S.C.
119(e).
FIELD OF THE INVENTION
[0002] The present disclosure concerns an apparatus and method for
fabrication of solid three dimensional (3D) articles of manufacture
from radiation curable (photocurable) resins. More particularly,
the present disclosure improves the quality of a three dimensional
(3D) article of manufacture through the automated removal of
particles from a build plane at which a photocurable resin is being
selectively solidified during fabrication.
BACKGROUND
[0003] Three dimensional (3D) printers are in rapidly increasing
use. One class of 3D printers includes stereolithography printers
having a general principle of operation including the selective
curing and hardening of radiation curable (photocurable) liquid
resins. A typical stereolithography system includes a containment
vessel holding the photocurable resin, a movement mechanism coupled
to a support surface, and a controllable light engine. The
stereolithography system forms a three dimensional (3D) article of
manufacture by selectively curing layers of the photocurable
resin.
[0004] In one system embodiment the vessel includes a transparent
sheet that forms part of a lower surface of the vessel. The support
surface is positioned above and in facing relation with the
transparent sheet. The following steps take place: (1) The movement
mechanism positions the support surface whereby a thin layer of the
photocurable resin resides between the support surface and the
transparent sheet. (2) The light engine transmits pixelated light
up through the transparent sheet to selectively cure a layer of the
photocurable resin proximate to and onto the support surface. The
focus of the pixelated light curing is referred to a "build plane."
(3) The movement mechanism then incrementally raises the support
surface. Steps (2) and (3) are repeated to form a three dimensional
(3D) article of manufacture having a lower face in facing relation
with the transparent sheet.
[0005] One difficulty is an accumulation of particles on the
transparent sheet and/or within the photocurable resin. The
particles are formed from the photocurable resin and are the result
of portions of a fabricated article that may break off and settle
into the resin. A required gap between the build plane and the
transparent sheet is very small. The lower face of the support
surface or three dimensional article of manufacture must therefore
be positioned very close (a small fraction of a millimeter
typically) to the transparent sheet in order to perform step (2)
above. During this positioning, the accumulated particles can
become compressed between the transparent sheet and the lower face.
These particles can be compressed and can damage the transparent
sheet and become embedded in the three dimensional article of
manufacture, possibly creating a defect. Damage to the transparent
sheet will affect its light transmissive properties and therefore
impact the quality of all subsequent fabrication. The transparent
sheet is also expensive and disruptive to replace. What is needed
is a system and method to prevent the particle accumulation and
facilitate their automated removal.
BRIEF DESCRIPTION OF THE FIGURES
[0006] FIG. 1 is a block diagram schematic of an exemplary
embodiment of a three dimensional printing system for forming a
three dimensional article of manufacture.
[0007] FIG. 2A is a block diagram schematic depicting a print
engine and a first embodiment of a configuration whereby the print
engine traps deleterious particles.
[0008] FIG. 2B is a block diagram schematic depicting a print
engine and a second embodiment of a configuration whereby the print
engine traps deleterious particles.
[0009] FIG. 2C is a block diagram schematic depicting a print
engine and a third embodiment of a configuration whereby the print
engine traps deleterious particles.
[0010] FIG. 3 is a plan view schematic of an exemplary fixture for
supporting a particle trapping sheet.
[0011] FIG. 4 is a sectional view taken from AA' of FIG. 3 with an
exemplary particle trapping sheet included.
[0012] FIG. 5 is a schematic plan view of an exemplary particle
trapping sheet.
[0013] FIG. 5A is a cross sectional view of an exemplary particle
trapping sheet taken through BB' of FIG. 5. This particle trapping
sheet embodiment corresponds to FIG. 2A.
[0014] FIG. 5B is a cross sectional view of an exemplary particle
trapping sheet taken through BB' of FIG. 5. This particle trapping
sheet embodiment corresponds to FIG. 2B.
[0015] FIG. 6A is a flowchart depicting a first embodiment of a
process for operating printing system 2 which corresponds to FIG.
2A.
[0016] FIG. 6B is a flowchart depicting a second embodiment of a
process for operating printing system 2 which corresponds to FIG.
2B.
[0017] FIG. 6C is a flowchart depicting a third embodiment of a
process for operating printing system 2 which corresponds to FIG.
2C.
SUMMARY
[0018] In a first aspect of the disclosure, a three dimensional
printing system includes a print engine, a fixture, and a
controller. The print engine further includes a vessel, a light
engine, and a movement mechanism. The vessel is for containing a
photocurable resin and has a lower portion with a transparent sheet
defining at least part of a lower surface of the vessel. The light
engine is configured to project radiation up through the
transparent sheet over a lateral build plane which defines a
maximum addressable lateral range of the light engine. The fixture
has a lower face that faces downwardly. The controller is
configured to: (1) position the lower face of the fixture at the
build plane which is at an operating distance from the transparent
sheet, and (2) operate the light engine and movement mechanism to
solidify a particle trapping sheet proximate to the transparent
sheet and substantially spanning the build plane and to thereby
trap particles that are present along the build plane.
[0019] In one implementation the controller includes a processor
coupled to an information storage device. The information storage
device includes a non-transient or non-volatile storage device
storing instructions that, when executed by the processor, control
the light engine and the movement mechanism. The controller can be
at one location or distributed among a plurality of locations in
the printing system. In a first embodiment the controller is
entirely within the print engine which operates as a standalone
three dimensional printer. In a second embodiment the controller
includes a control server that controls the overall printing system
and a print engine controller that is located within the print
engine. In the second embodiment the three dimensional printing
system includes various modules including one or more of a fixture
cassette, a post processing station, an inspection station, and a
robotic transport mechanism for transporting the fixture between
the modules.
[0020] In another implementation the fixture has a lower end
defining a recessed surface from which a plurality of projections
extend downwardly from the recessed surface to distal tips. The
particle trapping sheet defines an upper surface coupled to the
distal tips and an opposed lower surface. The opposed lower surface
further defines a plurality of tapering features. The controller is
further configured to operate the light engine and the movement
mechanism to form a three dimensional article of manufacture that
is coupled to the tapering features. The tapering features minimize
a surface area of connection between the three dimensional article
of manufacture and the particle trapping sheet in order to
facilitate the later physical separation of the particle trapping
sheet from the three dimensional article of manufacture.
[0021] In yet another implementation the printing system includes a
transport mechanism and the controller is further configured to:
(3) unload the fixture from the print engine, (4) load a new
fixture into the printing system, and (5) operate the light engine
and the movement mechanism to form a three dimensional article of
manufacture. The fixture used in steps (1) and (2) is a disposable
fixture that is used exclusively for forming the particle trapping
sheet and removing particles. The disposable fixture has a lower
end defining a recessed surface from which a plurality of
projections extend downwardly from the recessed surface to distal
tips. An upper surface of the particle trapping sheet is formed
onto the distal tips. The fixture used in steps (3) to (5) is a
reusable fixture that is used entirely for forming three
dimensional articles of manufacture.
[0022] In a further implementation the controller is configured to
operate the light engine and the movement mechanism to form a three
dimensional article of manufacture onto the fixture before forming
the particle trapping sheet. The particle trapping sheet includes a
plurality of upwardly extending extensions that form a framework
for supporting the particle trapping sheet onto the three
dimensional article of manufacture.
[0023] In a yet further implementation the particle trapping sheet
has an upper surface and an opposed lower surface. The particle
trapping sheet defines at least one opening passing from the upper
surface to the opposed lower surface to provide flow of
photocurable resin therethrough when the movement mechanism is
raising or lowering the fixture. Preferably the at least one
opening includes an array or plurality of openings that are
laterally distributed across the particle trapping sheet.
[0024] In another implementation the particle trapping sheet
includes a thin parallelepiped portion covering most or essentially
all of the lateral area of the build plane. The thickness is
minimized so as to minimize a required amount of resin for
fabricating the particle trapping sheet. The particle trapping
sheet also includes a framework of ribs or thickened portions to
provide mechanical support for the thin parallelepiped portion. In
some embodiments the particle trapping sheet includes tapering
features and/or extensions for coupling to a three dimensional
article of manufacture. The coupling occurs at a narrowed distal
tip. The tapering features and/or extensions can be laterally
aligned with the ribs so as to improve structural integrity. The
thin parallelepiped portion can define openings therethrough to
allow a flow of photocurable resin therethrough to facilitate
vertical movement of the fixture.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] FIG. 1 is a block diagram schematic of an exemplary
embodiment of a three dimensional printing system 2 for forming
three dimensional articles of manufacture. Three dimensional
printing system 2 includes fixture cassettes 4, print engines 6,
post-processing stations 8, inspection stations 10, a transport
mechanism 12, and a control server 14.
[0026] A fixture cassette 4 stores a stack of fixtures that are
utilized in print engine 6, post-process stations 8, and inspection
station 10. In some embodiments there are different fixtures stored
in different fixture cassettes 4. One stack of fixtures can be
disposable and utilized for a particle removal process. Another
stack of fixtures can be reusable and utilized for the formation
and transport of a three dimensional article of manufacture.
[0027] An embodiment of print engine 6 will be described in further
detail with respect to FIGS. 2A, 2B, and 2C. Post process stations
8 are for added processes for a three dimensional article of
manufacture after it is formed. Post processing stations can
include rinsing and cleaning stations, drying stations, and curing
stations, to name some examples. Inspection stations 10 can be
utilized to inspect for defects and/or to measure critical
dimensions for a three dimensional article of manufacture after
fabrication and post processing is complete.
[0028] Transport mechanism 12 is configured to pick up a fixture
from a fixture cassette 4 and to transfer it to a print engine 6.
Transport mechanism 12 also transfers the fixture to the post
process stations 8 and to the inspection stations 10. In one
embodiment, the transport mechanism includes a robotic gripper that
can move in three axes.
[0029] FIG. 2A is a schematic block diagram depicting print engine
6 and a first embodiment through which print engine 6 removes
deleterious particles. In this and other figures, mutually
perpendicular axes X, Y and Z will be used. Axes X and Y are
lateral axes. In some embodiments X and Y are also horizontal axes.
Axis Z is a central axis. In some embodiments Z is a vertical axis.
In some embodiments the direction +Z is generally upward and the
direction -Z is generally downward.
[0030] Print engine 6 includes a vessel 16 containing photocurable
resin 18. Vessel 16 includes a transparent sheet 20 that defines at
least a portion of a lower surface 22 of vessel 16. A light engine
24 is disposed to project light up through the transparent sheet 20
to selectively cure the photocurable resin 18 during formation of a
three dimensional article of manufacture 26. Light engine 24
includes light source 28 and spatial light modulator 30.
[0031] Between a lower face 32 of the three dimensional article of
manufacture 26 and the transparent sheet 20 is a thin layer 34 of
photocurable resin 18. As the light engine 24 operates, a portion
of the thin layer 34 of photocurable resin 18 is cured and
solidified at and proximate to a build plane 36. Build plane 36
defines a lateral extent (along X and Y) of a layer of photocure
resin that the light engine 24 is capable of curing when forming
the three dimensional article of manufacture 26.
[0032] Print engine 6 also includes a vertical movement mechanism
38 coupled to a fixture 40. Fixture 40 is for supporting the three
dimensional article of manufacture 26. Fixture 40 includes a lower
end 42 having an upwardly recessed surface 44 and projections 46
that extend downwardly from the recessed surface 44.
[0033] Print engine 6 includes print engine controller 48 that is
under control of control server 14 and is coupled to light engine
24 and to vertical movement mechanism 38. In the illustrated
embodiment, the print engine controller 48 controls the light
engine 24 and the movement mechanism 38 to form a particle trapping
sheet 50 before forming the three dimensional article of
manufacture 26. The particle trapping sheet 50 is first formed at
and proximate to the build plane 36 and just above the transparent
sheet 20. During formation of the particle trapping sheet 50 the
deleterious particulates are "bound up" in the particle trapping
sheet 50 so that they are removed from the vicinity of the
transparent sheet 20 to prevent build-up of particles and
subsequent damage. The lateral extent of the particle trapping
sheet 50 is preferably substantially the entire build plane 36.
[0034] The particle trapping sheet 50 includes tapering features 52
that taper between the particle trapping sheet 50 and the three
dimensional article of manufacture 26. These tapering feature 52
facilitate removal of the particle trapping sheet 50 from the three
dimensional article of manufacture 26 after processing is
complete.
[0035] FIG. 2B is a schematic block diagram depicting print engine
6 and a second embodiment through which print engine 6 removes
deleterious particles. In comparing FIGS. 2A and 2B, like reference
numerals indicate like elements. The discussion for FIG. 2B will be
limited to those features that necessarily make it different than
FIG. 2A.
[0036] In the illustrated embodiment of FIG. 2B, the print engine
controller 48 controls the light engine 24 and the movement
mechanism 38 to form a three dimensional article of manufacture 26
before forming a particle trapping sheet 50. The particle trapping
sheet 50 includes extensions 54 that form a framework for coupling
the particle trapping sheet 50 to the three dimensional article of
manufacture 26. As with FIG. 2A, the particle trapping sheet 50
preferably covers the entire build plane 36 of light engine 24.
[0037] FIG. 2C is a schematic block diagram depicting print engine
6 and a third embodiment through which print engine 6 removes
deleterious particles. In comparing FIGS. 2A, 2B, and 2C, like
reference numerals indicate like elements. The discussion for FIG.
2C will be limited to those features that necessarily make it
different than FIGS. 2A and 2C.
[0038] In the illustrated embodiment of FIG. 2C, the fixture 40 is
a disposable fixture 40 that is used entirely for forming the
particle trapping sheet 50 to remove the deleterious particles.
Other than being disposable, the fixture 40 is similar to the
fixture 40 illustrated with respect to FIG. 2A and includes the
upwardly recessed surface 44 from which the projections 46 extend
downwardly.
[0039] FIG. 3 is a plan view schematic of fixture 40 looking
upwardly in the +Z direction. The fixture 40 is shown having a
recessed surface 44 from which projections 46 extend in the
downward -Z direction. While the illustrated embodiment depicts
nine projections 46 it is to be understood that any number of
projections 46 can be employed. The use of closely spaced
projections 46 can allow a reduction in the thickness and rigidity
of the particle trapping sheet 50 because an unsupported distance
is thereby reduced. The fixture 40 also includes openings 56 for
allowing the photocurable resin 18 to pass through the fixture 40
as it is raised and lowered in the vessel 16.
[0040] FIG. 4 is a cross-sectional view of fixture 40 taken through
AA' of FIG. 3. FIG. 4 also includes the particle trapping sheet 50
which has been formed onto the projections 46 of the fixture 40.
The projections 46 taper in downward -Z direction toward a distal
end 58. Having a distal end 58 with a smaller cross sectional area
reduces the impact of the projections 46 upon particles that are
proximate to the transparent sheet 20.
[0041] FIG. 5 is a schematic plan view of an exemplary particle
trapping sheet 50. FIG. 5A is a cross section of a first embodiment
of the particle trapping sheet 50 that corresponds to the
embodiment depicted in FIG. 2A. The particle trapping sheet 50
includes a thin parallelepiped portion 60 covering most or
essentially all of a lateral area of the build plane 36. Minimizing
the thickness of the thin parallelepiped portion 60 minimizes an
amount of photocurable resin required to fabricate the particle
trapping sheet 50. The particle trapping sheet 50 also includes
thicker sections or ribs 62 that form a frame for supporting the
thin parallelepiped portion 60. The particle trapping sheet 50 also
includes tapering features 52 for attachment to the three
dimensional article of manufacture 26. The tapering geometry of the
tapering features 52 minimizes a lateral area of contact between
the particle trapping sheet 50 and the three dimensional article of
manufacture 26 to facilitate their later separation. The tapering
features 52 are preferably laterally aligned with ribs 62 to
improve structural integrity. The thin parallelepiped portion 60
also defines openings 64 that allow the flow of the photocurable
resin 18 as the particle trapping sheet 50 is raised or lowered in
the vessel 16. In this embodiment the particle trapping sheet 50 is
attached to the fixture 40 at an upper side and to the three
dimensional article of manufacture at a lower side defined by the
tapering features 52 as in FIG. 2A.
[0042] While only a few openings 64 are shown, it is to be
understood that a large number of such openings 64 can be defined.
The openings can be angled or stepped whereby particles are trapped
at the lateral positions of the openings 64. With a large number of
openings 64, they can have a relatively small lateral dimensions to
further enhance particle trapping in their vicinity.
[0043] FIG. 5B is a cross section of a second embodiment of the
particle trapping sheet 50 that corresponds to the embodiment
depicted in FIG. 2B. In comparing the embodiment of FIGS. 5A and
5B, like element numbers corresponding to like features. Therefore
this discussion will focus on differences. The illustrated particle
trapping sheet 50 includes extensions 54 for coupling the particle
trapping sheet 50 to a lower side of the three dimensional article
of manufacture 26. The extensions 54 may vary greatly in a vertical
extent in Z according to a geometry of the three dimensional
article of manufacture 26. Distal ends 66 of the extensions 54 are
of a minimal cross sectional area to facilitate the separation of
the particle trapping sheet 50 from the three dimensional article
of manufacture 26. Preferably the extensions 54 are laterally
aligned with ribs 62 to improve structural integrity.
[0044] FIG. 6A is a flowchart depicting a process 70 for operating
printing system 2 to fabricate a three dimensional article of
manufacture 26. All steps of this process are executed by control
server 14 and print engine controller 48 that control portions of
printing system 2 and print engine 6. Process 70 corresponds to the
description of FIG. 2A.
[0045] According to step 72, the transport mechanism 12 retrieves a
fixture 40 from a fixture cassette 4 and loads it into a print
engine 6. The fixture 40 is an embodiment similar to that discussed
with respect to FIG. 2A, FIG. 3, and/or FIG. 4. Upon loading the
fixture 40 into print engine 6, the movement mechanism 38 can
engage and vertically position the fixture 40.
[0046] According to step 74, the movement mechanism 38 lowers and
positions the fixture 40 whereby the distal ends 58 of projections
46 are positioned at build plane 36. Build plane 36 is at an
operating distance from the transparent sheet 20.
[0047] According to step 76, the print engine controller 48
operates the light engine 24 and the vertical movement mechanism 38
to form a particle trapping sheet 50 as is illustrated in FIG. 2A,
FIG. 4, or FIG. 5A. The particle trapping sheet 50 preferably spans
essentially the entire build plane 36 and is coupled to all of the
projections 46. Formation of the particle trapping sheet traps
loose particles that are primarily solidified photocurable resin.
Also as part of step 76, the connecting features 52 are formed that
taper downwardly.
[0048] According to step 78, the print engine controller 48
operates the light engine 24 and the vertical movement mechanism 38
to form a three dimensional article of manufacture 26 that couples
to the connecting features 52. A lateral cross sectional area over
which the connecting features 52 couple to the three dimensional
article of manufacture 26 is preferably minimized to facilitate
later separation.
[0049] According to step 79, the transport mechanism unloads the
fixture 40 from the print engine 6 and additional processes are
performed. These additional processes can include post processing,
inspection, and removal of the particle trapping sheet 50 from the
three dimensional article of manufacture 26. In one embodiment the
transport mechanism 12 sequentially transfers the fixture 40 to
different post process stations 8 and inspection stations 10. When
the particle trapping sheet 50 is removed it separates along the
lateral area between the connecting features 52 and the three
dimensional article of manufacture 26.
[0050] In an alternative embodiment the print engine 6 is a
standalone unit and steps 72 and 79 are performed manually. This
includes manual loading and unloading of fixture 40 as well as
cleaning, drying, UV curing, inspection, and removal of the
particle trapping sheet 50.
[0051] FIG. 6B is a flowchart depicting a process 80 for operating
printing system 2 to fabricate a three dimensional article of
manufacture 26. All steps of this process are executed by control
server 14 and print engine controller 48 that control portions of
printing system 2 and print engine 6. Process 80 corresponds to the
description of FIG. 2B.
[0052] According to step 82, the transport mechanism 12 retrieves a
fixture 40 from a fixture cassette 4 and loads it into a print
engine 6. The fixture 40 has a lower face 45 that faces
downwardly.
[0053] According to step 84, the movement mechanism lowers and
positions the lower face 45 of fixture 40 at the build plane 36.
The build plane 36 is at an operating distance from the transparent
sheet 20. According to step 86, the print engine controller 48
operates the light engine 24 and the vertical movement mechanism 38
to form a three dimensional article of manufacture 26.
[0054] According to step 88, the print engine controller 48
operates the light engine 24 and the vertical movement mechanism 38
to form a particle trapping sheet 50 as is illustrated in FIG. 2B
or FIG. 5B. The particle trapping sheet 50 preferably spans the
entire build plane 36. The particle trapping sheet 50 is coupled to
the three dimensional article of manufacture 26 via extensions 54.
The extensions 54 form a framework for properly supporting the
particle trapping sheet 50 in the vessel 24.
[0055] According to step 89, the transport mechanism unloads the
fixture 40 from the print engine 6 and additional processes are
performed. These additional processes can include post processing,
inspection, and removal of the particle trapping sheet 50 from the
three dimensional article of manufacture 26. In one embodiment the
transport mechanism 12 sequentially transfers the fixture 40 to
different post process stations 8 and inspection stations 10. When
the particle trapping sheet 50 is removed it separates along an
interface between the distal ends 66 of extensions 54 and the three
dimensional article of manufacture 26.
[0056] In an alternative embodiment the print engine 6 is a
standalone unit and steps 82 and 89 are performed manually. This
includes manual loading and unloading of fixture 40 as well as
cleaning, drying, UV curing, inspection, and removal of the
particle trapping sheet 50.
[0057] FIG. 6C is a flowchart depicting a process 90 for operating
printing system 2 to fabricate a three dimensional article of
manufacture 26. All steps of this process are executed by control
server 14 and print engine controller 48 that control portions of
printing system 2 and print engine 6. Process 90 corresponds to the
description of FIG. 2C.
[0058] According to step 92, the transport mechanism 12 retrieves a
disposable fixture 40 from a fixture cassette and loads it into a
print engine 6. The fixture can be an embodiment that is similar to
that discussed with respect to FIG. 2C, FIG. 3, or FIG. 4. Upon
loading the fixture 40 into print engine 6, the movement mechanism
38 can engage and vertically position the fixture 40.
[0059] According to step 94, the movement mechanism 38 lowers and
positions the fixture 40 whereby the distal ends 58 of projections
46 are positioned at build plane 36. Build plane 36 is at an
operating distance from the transparent sheet 20.
[0060] According to step 96, the print engine controller 48
operates the light engine 24 and the vertical movement mechanism 38
to form a particle trapping sheet 50 as is illustrated in FIG. 2C.
The particle trapping sheet 50 preferably spans essentially the
entire build plane 36 and is coupled to all of the projections 46.
Formation of the particle trapping sheet traps loose particles that
are primarily solidified photocurable resin.
[0061] According to step 98, the transport mechanism unloads the
disposable fixture 40 from the print engine 6. According to step
100, the transport mechanism loads a new fixture 40 into the print
engine 6. According to step 102, the print engine controller 48
operates the light engine 24 and the vertical movement mechanism 38
to form a three dimensional article of manufacture 26.
[0062] According to step 104, the transport mechanism unloads the
fixture 40 from the print engine 6 and additional processes are
performed. These additional processes can include post processing,
and inspection. In one embodiment the transport mechanism 12
sequentially transfers the fixture 40 to different post process
stations 8 and inspection stations 10.
[0063] The specific embodiments and applications thereof described
above are for illustrative purposes only and do not preclude
modifications and variations encompassed by the scope of the
following claims.
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