U.S. patent application number 17/566112 was filed with the patent office on 2022-04-21 for 3d printing with variable voxel sizes.
The applicant listed for this patent is UNIVERSITY OF SOUTHERN CALIFORNIA. Invention is credited to Yong Chen, Yuanrui Li, Huachao Mao, Wei Wu.
Application Number | 20220118703 17/566112 |
Document ID | / |
Family ID | 1000006066311 |
Filed Date | 2022-04-21 |
United States Patent
Application |
20220118703 |
Kind Code |
A1 |
Chen; Yong ; et al. |
April 21, 2022 |
3D PRINTING WITH VARIABLE VOXEL SIZES
Abstract
Methods, systems, and apparatus for multi-scale
stereolithography. The apparatus includes a light source for
providing a laser beam having a first shape and a first size. The
apparatus includes a dynamic aperture having multiple apertures
that are of the same or different sizes or shapes. The dynamic
aperture is configured to receive the laser beam and modify at
least one of the shape or the size of the laser beam. The apparatus
includes a platform for holding an object to be printed. The
apparatus includes a processor connected to at least one of the
light source, the dynamic aperture or the platform. The processor
is configured to move the platform to direct the laser beam or
direct the laser beam to cure resin onto the object to be printed
using a first aperture of the multiple apertures to form the
object.
Inventors: |
Chen; Yong; (Los Angeles,
CA) ; Li; Yuanrui; (Los Angeles, CA) ; Mao;
Huachao; (Los Angeles, CA) ; Wu; Wei; (Los
Angeles, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNIVERSITY OF SOUTHERN CALIFORNIA |
Los Angeles |
CA |
US |
|
|
Family ID: |
1000006066311 |
Appl. No.: |
17/566112 |
Filed: |
December 30, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15993197 |
May 30, 2018 |
11230057 |
|
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17566112 |
|
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|
|
62513643 |
Jun 1, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 64/268 20170801;
B29C 64/393 20170801; B23K 26/067 20130101; B29C 64/129 20170801;
B33Y 50/02 20141201; B33Y 30/00 20141201; B29C 64/245 20170801;
B29C 64/286 20170801; B29C 67/04 20130101; B33Y 10/00 20141201;
B29C 64/277 20170801 |
International
Class: |
B29C 64/268 20060101
B29C064/268; B29C 64/393 20060101 B29C064/393; B29C 64/277 20060101
B29C064/277; B29C 64/245 20060101 B29C064/245; B29C 67/04 20060101
B29C067/04; B33Y 10/00 20060101 B33Y010/00; B33Y 30/00 20060101
B33Y030/00; B23K 26/067 20060101 B23K026/067; B29C 64/286 20060101
B29C064/286; B29C 64/129 20060101 B29C064/129 |
Claims
1. A multi-scale stereolithography apparatus, comprising: a light
source; a dynamic aperture positioned after the light source; one
or more lenses positioned before or after the dynamic aperture; one
or more mirrors positioned after the dynamic aperture; a stage
connected to the dynamic aperture; and a processor connected to at
least one of the light source, the dynamic aperture or the
stage.
2. The multi-scale stereolithography apparatus of claim 1, wherein
the one or more lenses is positioned before the dynamic aperture to
narrow an original light beam before the original light beam enters
the dynamic aperture.
3. The multi-scale stereolithography apparatus of claim 1, wherein
the stage is configured to move based on a toolpath adapted to
optimize resolution or speed along an XY plane of a layer of a
fabricated part.
4. The multi-scale stereolithography apparatus of claim 1, wherein
the one or more lenses is positioned before the dynamic aperture to
narrow an original light beam before the original light beam enters
the dynamic aperture and wherein the stage is configured to move
based on a toolpath adapted to optimize resolution or speed along
an XY plane of a layer of a fabricated part.
5. The multi-scale stereolithography apparatus of claim 1, wherein
the light source produces a light beam having a first dimension at
a first time point and a second dimension at a second time
point.
6. The multi-scale stereolithography apparatus of claim 1, wherein
the stage is a linear or rotary stage.
7. The multi-scale stereolithography apparatus of claim 1, wherein
the dynamic aperture has a plurality of apertures that are of
different sizes or shapes.
8. The multi-scale stereolithography apparatus of claim 1, wherein
the dynamic aperture has a first aperture at a first time point and
a second aperture at a second time point.
9. The multi-scale stereolithography apparatus of claim 1, further
comprising a resin tank interfacing with the one or more
mirrors.
10. The multi-scale stereolithography apparatus of claim 1, wherein
the light source produces a light beam and the light beam is
configured to cure resin in a resin tank to create a portion of a
fabricated part.
11. The multi-scale stereolithography apparatus of claim 9, further
comprising a platform interfacing with the light source.
12. A multi-scale stereolithography apparatus, comprising: a beam
optics device, the beam optics device including a light source, a
dynamic aperture, one or more mirrors, one or more lenses, and a
stage; and a processor connected to the beam optics device.
13. The multi-scale stereolithography apparatus of claim 12,
wherein the one or more lenses is positioned before the dynamic
aperture.
14. The multi-scale stereolithography apparatus of claim 12,
wherein the light source produces a plurality of light beams and
the plurality of light beams cures a resin onto a printed object,
the resin having a first thickness when a first light beam is used
and the resin having a second thickness when a second light beam is
used.
15. The multi-scale stereolithography apparatus of claim 12,
wherein the dynamic aperture has a first aperture that allows a
small-scale light source to pass through and a second aperture that
allows a large-scale light source to pass through.
16. The multi-scale stereolithography apparatus of claim 12,
further comprising a resin tank interfacing with the beam optics
device and a platform interfacing with the beam optics device the
platform holding a printed object.
17. The multi-scale stereolithography apparatus of claim 12,
wherein the stage is at a first position at a first time point and
a second position at a second time point to modify a shape or a
size of a first laser beam to a second laser beam with a shape or a
size that is different than the shape or size of the first laser
beam.
18. A multi-scale stereolithography apparatus, comprising: a light
source for providing a laser beam having a first shape and a first
size; a dynamic aperture having a plurality of apertures that are
of different sizes or shapes, the dynamic aperture configured to:
receive the laser beam, and modify at least one of the shape or the
size of the laser beam; a platform for holding an object to be
printed; and a processor connected to at least one of the light
source, the dynamic aperture or the platform and configured to:
move the platform or direct the laser beam to cure resin onto the
object to be printed using a first aperture of the plurality of
apertures to form the object.
19. The multi-scale stereolithography apparatus of claim 18,
further comprising one or more lenses for narrowing an original
laser beam prior to modifying the original laser beam.
20. The multi-scale stereolithography apparatus of claim 18,
further comprising one or more mirrors that direct the laser beam
at the resin to cure the resin onto the object to be printed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of U.S. Non-Provisional
patent application Ser. No. 15/993,197 titled "3D PRINTING WITH
VARIABLE VOXEL SIZES," filed on May 30, 2018 and claims priority to
and the benefit of U.S. Provisional Patent Application No.
62/513,643 titled "3D PRINTING WITH VARIABLE VOXEL SIZES BASED ON
APERTURE PLATE," filed on Jun. 1, 2017, the entirety of which is
hereby incorporated by reference herein.
BACKGROUND
Field
[0002] This specification relates to a system, method or apparatus
for multi-scale three-dimensional (3D) printing.
Description of the Related Art
[0003] Current stereolithography (SL) fabricates three-dimensional
(3D) objects in a single scale level, e.g., printing macro-scale or
micro-scale objects. However, it is difficult for SL printers to
fabricate a 3D macro-scale object with micro-scale features. When
fabricating using SL, there are various tradeoffs between part
size, resolution and speed.
[0004] For example, there is a tradeoff between fabrication
resolution and fabrication speed. An SL printer that has a high
resolution requires a longer period of time to print or fabricate
the feature or object. An SL printer that has a low resolution,
however, sacrifices resolution to fabricate or print the object
faster. In another example, there is a tradeoff between scalability
and fabrication speed. As the size of the object to be printed
increases, an SL printer requires more time to print the object,
and thus, the speed of printing the object decreases. An SL printer
that fabricates micro-scale features requires a significant amount
of time to build objects of large sizes. In another example, there
is a tradeoff between feature resolution and part size. An SL
printer that has a large part size has difficulty in fabricating
highly detailed features.
[0005] Accordingly, there is a need for a multi-scale SL apparatus
or process that optimizes the laser beam to fabricate features at
different scales.
SUMMARY
[0006] In general, one aspect of the subject matter described in
this specification may be embodied in a multi-scale
stereolithography (SL) apparatus. The apparatus includes a light
source for providing a laser beam having a first shape and a first
size. The apparatus includes a dynamic aperture having multiple
apertures that are of different sizes or shapes. The dynamic
aperture is configured to receive the laser beam and modify at
least one of the shape or the size of the laser beam. The apparatus
includes a platform for holding an object to be printed. The
apparatus includes a processor connected to at least one of the
light source, the dynamic aperture or the platform. The processor
is configured to move the platform and to direct the laser beam to
cure resin onto the object to be printed using a first aperture of
the multiple apertures to form the object.
[0007] These and other embodiments may optionally include one or
more of the following features. The apparatus may include a linear
or rotation stage for positioning the dynamic aperture. The
apparatus may be in a first position. The processor may be
connected to the linear or rotation stage. The processor may be
configured to move the linear or rotation stage to a second
position from the first position to position a second aperture of
the multiple apertures in a path of the laser beam to modify the
shape or the size of the laser beam to a second shape or a second
size.
[0008] The cured resin may be of a second shape or a second size.
The cured resin onto the printed object may be of a second shape or
a second size. The cured resin may be of a first thickness when the
first aperture is used and may be of a second thickness when a
second aperture is used.
[0009] The multiple apertures may include a first aperture of a
first size, a second aperture of a second size and a third aperture
of a third size. The processor may be configured to determine a
first offset based on the first size, a second offset based on the
second size and a third offset based on the third size. The
processor may be configured to slice the object to be printed into
multiple layers. Each layer may have the same or a different
thickness. The processor may be configured to generate one or more
toolpaths to form the object to be printed based on the first
offset, the second offset, the third offset and the thickness of
each layer. The thickness of a first layer may be different than a
thickness of a second layer. The multiple apertures may include a
first aperture that allows a small-scale light source to pass
through and a second aperture that allows a large-scale light
source to pass through. The multiple apertures may include a first
aperture having a first shape and a second aperture having a second
shape. The first shape may be different from the second shape.
[0010] In another aspect, the subject matter may be embodied in a
method of providing differing light beams in a multi-scale
stereolithography (SL) apparatus. The method includes providing,
using a light source, an original light beam having a beam
dimension. The method includes adjusting, using a processor, a
dynamic aperture to a first aperture. The method includes
projecting, using the light source, the original light beam through
the first aperture to form a second light beam with a small-scale
beam dimension and onto a resin. The method includes adjusting,
using the processor, the dynamic aperture to a second aperture. The
method includes projecting, using the light source, the original
light beam through the second aperture to form a third light beam
with a large-scale beam dimension and onto the resin.
[0011] In another aspect, the subject matter may be embodied in a
multi-scale stereolithography apparatus. The apparatus includes a
light source for providing a laser beam having a size. The
apparatus includes a platform for holding an object to be printed.
The apparatus includes a dynamic aperture having multiple apertures
that are of different sizes. The dynamic aperture is configured to
receive the laser beam and to modify the size of the laser beam.
The apparatus includes a linear stage (or a rotation stage)
connected to the dynamic aperture and configured to move the
dynamic aperture among the multiple apertures. The apparatus
includes a processor connected to at least one of the light source,
the dynamic aperture or the linear or rotation stage. The processor
is configured to move the linear or rotation stage to a first
position to position a first aperture of the multiple apertures
into a path of the laser beam and move the platform or direct the
laser beam to cure resin onto the object to be printed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Other systems, methods, features, and advantages of the
present invention will be apparent to one skilled in the art upon
examination of the following figures and detailed description.
Component parts shown in the drawings are not necessarily to scale,
and may be exaggerated to better illustrate the important features
of the present invention.
[0013] FIG. 1 shows an example multi-scale stereolithography (SL)
apparatus according to an aspect of the invention.
[0014] FIG. 2 shows a beam optics device of the multi-scale SL
apparatus of FIG. 1 according to an aspect of the invention.
[0015] FIG. 3 shows different apertures with different sized and/or
shaped pinholes for the apertures of the dynamic aperture according
to an aspect of the invention.
[0016] FIG. 4 shows an example of an aperture with a pillar shape
and the corresponding pillar-shaped part formed by the multi-scale
SL apparatus of FIG. 1 using the pillar-shaped aperture according
to an aspect of the invention.
[0017] FIG. 5 is a flow diagram of an example process for
fabricating different regions or portions of the part using the
multi-scale SL apparatus of FIG. 1 according to an aspect of the
invention.
[0018] FIG. 6 is a flow diagram of an example process for
generating one or more toolpaths used by the multi-scale SL
apparatus of FIG. 1 to fabricate the different regions or portions
of the part according to an aspect of the invention.
[0019] FIG. 7 shows resin recoating the part after a layer of the
part has been fabricated according to an aspect of the
invention.
[0020] FIG. 8 is a table that compares different SL processes
and/or apparatuses over different metrics according to an aspect of
the invention.
[0021] FIG. 9 shows a large layer of a part and the corresponding
interior portion and boundary portion according to an aspect of the
invention.
DETAILED DESCRIPTION
[0022] Disclosed herein are systems, apparatuses, devices and/or
methods for a multi-scale stereolithography (SL) apparatus
("multi-scale SL apparatus") that optimizes the three-dimensional
fabrication of a part or an object. Particular embodiments of the
subject matter described in this specification may be implemented
to realize one or more of the following advantages. The multi-scale
SL apparatus has multiple apertures of the same or differing shapes
and/or sizes. The multi-scale SL apparatus directs a light source,
such as a laser, through at least one of the multiple apertures of
the same or differing shapes and/or sizes to optimize both the
resolution and the speed. For example, the multi-scale SL apparatus
may use a high-resolution laser beam to form micro-features to
provide higher resolution and/or fidelity on a part or an object
and may use a lower resolution laser beam to form macro-features to
increase the speed at which the part or the object is fabricated or
printed. This optimizes both the resolution and the speed in the XY
planar direction.
[0023] Other benefits and advantages of the multi-scale SL
apparatus include the capability to optimize the resolution and the
speed in the Z direction. The multi-scale SL apparatus slices
different portion of the part into layers with the same or
different thicknesses and fabricates the different layers using
laser beams with different dimensions. This optimizes the
resolution and the speed in the Z direction. Additionally, the
multi-scale SL apparatus may use different shapes to achieve
different levels of the resolution and/or the speed when forming
features on the part.
[0024] FIG. 1 shows a multi-scale SL apparatus 100. The multi-scale
SL apparatus 100 forms laser beams of different dimensions to form
micro-features and/or macro-features to optimize the resolution and
the speed of the fabrication process. Conventional approaches use a
single scale in size to print or fabricate features on a part or an
object. Whereas, the multi-scale SL apparatus 100 has a dynamic
aperture with multiple apertures having the same or different
pinholes that control or modify the shape, e.g., pattern, and/or
the resolution, i.e., size, of the laser beam to control the shape
and/or the size of the cured portion onto the part or the object
(hereinafter referred to as "part"). The multi-scale SL apparatus
100 may control the resolution and the speed of the fabrication
process by switching between different apertures with different
pinholes having different sizes and/or shapes. The multi-scale SL
apparatus 100 optimizes the printing or the fabrication of the
features on the part for both the resolution and the speed.
[0025] The multi-scale SL apparatus 100 includes a processor 102, a
light source 104, a dynamic aperture 106, one or more lenses 108, a
memory 110 and/or a platform 112. The multi-scale SL apparatus 100
may include a linear or rotation stage 114, a user interface 116, a
resin tank 118 and/or one or more mirrors 120. The light source
104, the dynamic aperture 106, the one or more lenses 108, and the
one or more mirrors 120 may form a beam optics device 200, as shown
in FIG. 2, for example.
[0026] The multi-scale SL apparatus 100 includes a processor 102.
The processor 102 may include one or more data processing
apparatuses, such as a controller or a computer. The processor 102
may access the memory 110 to perform programmed instructions stored
on the memory 110, move the platform 112, adjust the dynamic
aperture 106 or perform other functions to cure the resin to print
or fabricate the part 122 or features on the part 122. For example,
the processor 102 may move a linear or rotation stage 114 to
position one of the pinholes of an aperture of the dynamic aperture
106 into the path of the laser beam outputted from the light source
104. The laser beam passes through the dynamic aperture 106 and
cures the resin to form a feature on the part 122.
[0027] A memory 110 may be coupled to the processor 102. The memory
110 may be local or remote. The memory 110 may store instructions
to execute on the processor 102 and may include a computer-readable
medium, such as one or more of a RAM or other volatile or
non-volatile memory. The memory 110 may be a non-transitory memory
or a data storage device, such as a hard disk drive, a solid-state
disk drive, a hybrid disk drive, or other appropriate data storage,
and may further store machine-readable instructions, which may be
loaded and executed by the processor 102. The memory 110 may store,
for example, a computer-aided design (CAD) drawing or model. The
CAD drawing or model may be a precision model that provides
instructions to generate a toolpath for the printing or the
fabrication of a part.
[0028] The multi-scale SL apparatus includes a user interface 116.
The user interface 116 may be a display or a personal device, e.g.,
a mobile phone, a tablet, a personal computer, that is connected to
the processor 102. The user interface 116 may include any device
capable of receiving user input, such as a button, a dial, a
microphone, or a touch screen, and any device capable of output,
such as a display, a speaker, or a refreshable braille display. The
user interface 116 allows a user to interact with the processor
102.
[0029] The multi-scale SL apparatus 100 includes a light source
104. The light source 104 may be a laser diode or other laser. The
light source 104 outputs a laser beam. The laser beam may have a
dimension. The dimension may include a shape and/or a size. The
processor 102 may be connected to the light source 104 to operate
the light source 104, such as to turn the light source 104 on or
off. The processor 102 may intermittently turn the light source 104
on or off.
[0030] The multi-scale SL apparatus 100 includes a dynamic aperture
106. The dynamic aperture 106 may have multiple apertures. The
different apertures each have different sized and/or shaped
pinhole. In some embodiments, the different apertures may have the
same sized and/or shaped pinholes.
[0031] For example, the dynamic aperture 106 may have an aperture
with a small-scale pinhole that forms a light beam into a light
beam with a small-scale dimension, an aperture with a medium-scale
pinhole that forms the light beam into a light beam with a
medium-scale dimension, and an aperture with a large-scale pinhole
that forms the light beam into a light beam with a large-scale
dimension. The small-scale dimension may be smaller in size than
the medium-scale dimension and smaller in size than the large-scale
dimension. The medium-scale dimension may be larger in size than
the small-scale dimension and smaller in size than the large-scale
dimension. The large-scale dimension may be larger in size than the
small-scale dimension and larger in size than the medium-scale
dimension.
[0032] In another example, the dynamic aperture 106 may have
apertures with a large-scale pinhole 302, a small-scale pinhole
304, a matrix of pinholes in a pattern 306 or a densely populated
matrix of pinholes in a pattern 308, as shown in FIG. 3, for
example. FIG. 3 shows different patterns for the pinholes of the
different apertures of the dynamic aperture 106. The differently
shaped pinholes may be useful in fabricating a functional surface
with different micro patterns of pillars, as shown in FIG. 4, for
example.
[0033] In order to adjust the dynamic aperture 106 to use different
apertures with different pinholes of varying sizes and/or shapes,
the dynamic aperture 106 may be mounted on a linear stage 114. The
processor 102 may cause the linear or rotation stage 114 or
rotation stage to move in one or more directions to select, set or
use one of the apertures with one of the pinholes for the laser
beam to pass through. The processor 102 moves the linear or
rotation stage 114 to a first position to select an aperture with a
small-scale pinhole, a second position to select an aperture with a
medium-scale pinhole, or a third position to select an aperture
with a large-scale pinhole, for example.
[0034] Other components modify and/or direct the laser beam within
the beam optics device 200. FIG. 2 shows the arrangement of the
various components of the beam optics device 200 and the path of
the laser beam through the beam optics device 200. The beam optics
device 200 may include the light source 104, the one or more lenses
108, the dynamic aperture 106 and/or one or more mirrors 120.
[0035] The multi-scale SL apparatus 100 includes one or more lenses
108 that focus and/or narrow the laser beam. The one or more lenses
108 may include a collimating lens 108a and/or a focus lens 108b.
The collimating lens 108a may narrow a laser beam that passes
through. The collimating lens 108a may be positioned before the
dynamic aperture 106 to narrow the laser beam prior to entering the
dynamic aperture 106. The focus lens 108b may focus a laser beam
that passes through. The focus lens 108b may be positioned after
the dynamic aperture 106 and before a mirror 120 to focus the laser
beam onto the mirror 120.
[0036] The multi-scale SL apparatus 100 may include one or more
mirrors 120. The one or more mirrors 120 may direct the laser beam
onto resin to be cured to form a part 122 or a feature onto the
part 122. The one or more mirrors may include a galvo mirror that
deflects and/or redirects the laser beam onto the resin to be
cured. The one or more mirrors 120 may direct the laser beam onto
resin to cure the resin to form the part 122 and/or form a feature
on the part 122. The multi-scale SL apparatus 100 may include a
resin tank 118 that stores and holds the resin and/or a platform
112 that holds the part 122. The platform 112 may have a motor
and/or an actuator. The processor 102 may move the platform 112
using the motor and/or the actuator to move the platform 112
vertically to adjust the thickness of the fabricated layer.
[0037] The laser beam from the light source 104 may pass through
and be narrowed by the collimating lens 108a. The dynamic aperture
106 receives the laser beam that passes through the collimating
lens 108a. The dynamic aperture 106, which may be positioned or set
by moving the linear or rotation stage 114, has any number of
pinholes with different shapes and/or sizes that modify the laser
beam and provide the laser beam to the focus lens 108b. Then, the
focus lens 108b focuses the laser beam onto a galvo mirror, for
example, to be redirected at the resin in the resin tank 118. The
resin is cured to form the part or a feature of the part 122.
[0038] FIG. 4 shows a matrix of pinholes 402. The multi-scale SL
apparatus 100 may set the dynamic aperture 106 to use the aperture
with a matrix of pinholes 402 to modify the laser beam to form a
pillar-shaped part 404, for example. The multi-scale SL apparatus
100 may use other shapes, such as a rectangular shape, a triangular
shape or other polygon shape to form other types or other shaped
parts. The differently shaped beams allow for simultaneous curing
of a part to increase fabrication speed and provide for specific
micro patterns to modify the surface texture of the part 122.
[0039] FIG. 5 describes the process 500 to fabricate the part 122
and/or a feature on the part 122 using the multi-scale SL apparatus
100. One or more computers or one or more data processing
apparatuses, for example, the processor 102 of the multi-scale SL
apparatus 100 of FIG. 1, appropriately programmed, may implement
the process 500.
[0040] The multi-scale SL apparatus 100 provides a laser beam using
a light source 104 (502). The light source 104 may be a laser
diode. The light source 104 may provide the laser beam that is
subsequently modified and used to cure the resin to form the part
122 and/or a feature on the part 122. The light source 104 may
provide the laser beam to one or more lenses 108, such as a
collimating lens 108a, to narrow the laser beam prior to modifying
the laser beam into a different shape and/or size to form a second
laser beam.
[0041] The multi-scale SL apparatus 100 may obtain the toolpath
from the memory 110 (503). The toolpath may include information as
to the portion width to be fabricated along the XY planar
direction, e.g., the boundary portion or interior portion, the one
or more offsets, and the corresponding aperture to be used for the
portions, e.g., the small-scale aperture, the medium-scale aperture
or the large-scale aperture. The toolpath may include other
information including the thickness of each layer within each
portion, such as the boundary portion and/or the interior portion,
and the corresponding aperture to be used for the layers within the
portion.
[0042] The multi-scale SL apparatus 100 determines an initial
position and/or an initial setting of the dynamic aperture 106
(504). The initial position and/or the initial setting may be based
on the toolpath. The dynamic aperture 106 may have multiple
apertures with different types and/or sizes of pinholes that are
each associated with a different position and/or setting. The
multi-scale SL apparatus 100 may determine the position and/or the
setting based on a toolpath. FIG. 5 describes the process 500 for
generating one or more toolpaths.
[0043] The multi-scale SL apparatus 100 may determine that the
initial setting is a small-scale setting, a medium-scale setting
and/or a large-scale setting, for example. The different settings
and/or different positions are associated with different apertures
with different sized pinholes. The small-scale setting may be
associated with an aperture with a pinhole with a small-scale size.
The medium-scale setting may be associated with an aperture with a
pinhole with a medium-scale size. The large-scale setting may be
associated with an aperture with a pinhole with a large-scale size.
Other settings may be associated with other pinholes with different
shapes and/or sizes.
[0044] The multi-scale SL apparatus 100 may associate each setting
with a position for the dynamic aperture 106. The dynamic aperture
106 may be connected or mounted to a linear or rotation stage 114.
The processor 102 may move the linear or rotation stage 114 to
position different apertures with different sized and/or shaped
pinholes into the path of the laser beam based on the setting. For
example, a first position may place the small-scale pinhole into
the path of the laser beam, a second position may place the
medium-scale pinhole into the path of the laser beam and a third
position may place the large-scale pinhole into the path of the
laser beam.
[0045] The multi-scale SL apparatus 100 sets or positions one of
the pinholes of the dynamic aperture 106 into the path of the laser
beam to form another laser beam based on the initial setting or the
initial position (506). The multi-scale SL apparatus 100 uses the
pinhole to modify the laser beam to form a differently shaped
and/or sized laser beam. The multi-scale SL apparatus 100 may set
or position a small-scale pinhole into the path of the laser beam
to form a small-scale laser beam. The multi-scale SL apparatus 100
may use the small-scale laser beam to form a boundary portion
before switching to a different aperture to use a large-scale laser
beam to form an interior portion. In some implementations, the
multi-scale SL apparatus 100 uses the large-scale laser beam to
form the interior portion before switching to a different aperture
to use the small-scale laser beam to form the boundary portion.
[0046] In order to set or position the pinhole into the path of the
laser beam, the multi-scale SL apparatus 100 may move or position a
linear or rotation stage 114 from one position to another position
to set the pinhole into the path of the laser beam. The position of
the linear or rotation stage 114 places a corresponding aperture in
the path of the laser beam. For example, the multi-scale SL
apparatus 100 may move the linear or rotation stage 114 in one
direction to transition from a medium-scale aperture to a
small-scale aperture and/or move the linear or rotation stage 114
in the other direction to transition from the medium-scale aperture
to a large-scale aperture.
[0047] The multi-scale SL apparatus 100 may use the small-scale
aperture to position the small sized pinhole into the path of the
laser beam, for example, to provide for high-resolution within the
boundary portion, which has more detailed features than the
interior portion. The multi-scale SL apparatus 100 may use the
large-scale aperture to position the large sized pinhole into the
path of the laser beam, for example, to provide for faster print
speeds within the interior portion, which does not have detailed
features. Thus, the multi-scale SL apparatus 100 optimizes both the
resolution and the speed along the XY planar direction.
[0048] The multi-scale SL apparatus 100 moves the platform 112 or
direction of the laser beams to fabricate a region of the part 122
based on the toolpath (508). The multi-scale SL apparatus 100
controls the direction of the laser beams using the one or more
mirrors 120 to cure resin onto the part 122 along the XY planar
direction. The multi-scale SL apparatus 100 uses the one or more
offsets as boundaries.
[0049] The multi-scale SL apparatus 100 uses the thickness
information of each layer to move the platform 112 to fabricate the
region of the part 122 in the Z direction. Since the thickness of
each layer within the boundary portion is less than the thickness
of each layer within the interior portion, the multi-scale SL
apparatus 100 may use a small-scale pinhole to fabricate each layer
within the boundary portion, e.g., to provide high resolution, and
a large-scale pinhole to fabricate each layer within the interior
portion, e.g., to provide faster print speeds. The multi-scale SL
apparatus 100 adjusts the platform 112 in the vertical direction by
the thickness of each layer upon completion of fabrication of one
of the layers.
[0050] The multi-scale SL apparatus 100 fabricates the part 122
(510). The multi-scale SL apparatus 100 may activate the light
source 104 when the at least one of the light source 104 or the
platform 112 are positioned to fabricate or print the part 122. The
multi-scale SL apparatus may use one or more lenses 108 and/or one
or more mirrors 120 to focus and direct the laser beam from the
light source 104 at the resin to cure the resin onto the region of
the part 122. The resin may be stored in the resin tank 118. When
the multi-scale SL apparatus 100 finishes one layer of the part,
the multi-scale SL apparatus 100 may adjust a height of the
platform 112 by the thickness to fabricate the next layer of the
part 122.
[0051] After the multi-scale SL apparatus 100 uses the small-scale
laser beam to fabricate the part 122, e.g., the boundary portion,
the multi-scale SL apparatus 100 may recoat the fabricated portion
of the part 122 with resin (512). For example, the multi-scale SL
apparatus 100 may recoat the boundary portion that is fabricated
using the small-scale laser beam with resin. In some
implementations, since the multi-scale SL apparatus slices the
boundary portion into multiple small layers, the multi-scale SL
apparatus does not need to recoat the small layer with resin prior
to moving the platform 112 upward to form another small layer
within the boundary portion. Even if the multi-scale SL apparatus
100 recoats the small layer within the boundary portion, the amount
of time to recoat the small layer within the boundary portion is
less than the time to recoat a large layer. This is because the
amount of resin necessary to displace the volume that is vacated
when the platform 112 moves after finishing a small layer with a
small-scale laser beam is less than the amount of resin necessary
after finishing a large layer with a large-scale laser beam. Thus,
the time necessary to recoat is less after finishing the small
layer with the small-scale laser beam than after finishing the
large layer with the large-scale laser beam. FIG. 7 shows the part
122 within the resin tank 118. When the part 122 is moved upward, a
gap 702 is formed. The surrounding resin 704 fills-in the gap 702
to recoat the part 122 after being moved upward. Thus, the
multi-scale SL apparatus 100 may not need to wait a period of time
to recoat the part 122 after being moved upward because the volume
of the gap 702 is naturally filled by the resin 704 within a small
amount of time.
[0052] After the multi-scale SL apparatus 100 recoats the portion
of the part 122, the multi-scale SL apparatus may repeat the
process for another portion, such as the interior portion, to
fabricate the other portion of the part 122. The multi-scale
apparatus may determine a new setting or position of the dynamic
aperture 106 to set or position a different aperture, such as an
aperture with a large-scale pinhole, into the path of the laser
beam based on a toolpath (514).
[0053] Different sizes, shapes and/or thicknesses have different
advantages. The multi-scale SL apparatus 100 uses these different
pinholes to take advantage of the different advantages for
different portions of the part 122. For example, a small-scale
laser beam and a small layer thickness may cure features with a
high resolution, while a large-scale laser beam may quickly cure a
large portion of resin and a large layer thickness. The multi-scale
SL apparatus 100 may automatically select the appropriate aperture
with the appropriate pinhole that corresponds with a laser beam
that optimizes these different advantages based on the
toolpath.
[0054] Once the multi-scale SL apparatus 100 determines the new
setting or position, the multi-scale SL apparatus 100 sets or
positions the associated aperture with the appropriate pinhole into
the path of the laser beam based on the new setting or position to
modify the laser beam into another shape and/or size (516). That
is, the multi-scale SL apparatus 100 may move the linear or
rotation stage 114 from the initial position to a new position that
sets or positions the different aperture with the different pinhole
that optimizes a corresponding feature, such as fabrication speed,
into the path of the laser beam. After the multi-scale SL apparatus
100 sets or positions the associated pinhole, the multi-scale SL
apparatus 100 moves the platform 112 or directs the laser beam to
fabricate another portion of the part 122 (518) and fabricates the
other portion of the part 122 (520).
[0055] FIG. 6 describes the process 600 to generate one or more
toolpaths used to fabricate the part or feature of the part using
the multi-scale SL apparatus 100. One or more computers or one or
more data processing apparatuses, for example, the processor 102 of
the multi-scale SL apparatus 100 of FIG. 1, appropriately
programmed, may implement the process 600.
[0056] The multi-scale SL apparatus 100 obtains or generates a
digital model of the part 122 (602). The digital model may be a
computer-aided design (CAD) drawing or other digital model. The
digital model is a technical drawing used by computer software to
design curves, figures, solids or other objects, such as the part,
in three-dimensional (3D) space. The multi-scale SL apparatus 100
may receive or obtain the digital model via user input from the
user interface 116 or may be obtained from the memory 110.
[0057] The multi-scale SL apparatus 100 slices the digital model of
the part 122 into multiple large layers (604). The large layer may
have a large thickness, which may be greater in thickness than a
small thickness of a small layer, respectively. The large layer may
have a thickness of approximately 100 .mu.m, for example.
[0058] The multi-scale SL apparatus 100 determines a size of one or
more offsets (606). The one or more offsets may be based on the
size and/or the shape of the one or more pinholes of the different
apertures, i.e., the aperture size, of the dynamic aperture 106
and/or the contours of the part 122 that is to be printed. The
different shapes and/or sizes may be pre-configured and/or may be
user inputted into the multi-scale SL apparatus 100. In some
implementations, the multi-scale SL apparatus 100 may detect the
different shapes and/or sizes of the one or more pinholes. The size
of an offset may be a function of the radius of the corresponding
aperture of the dynamic aperture 106 and a thickness of the layer
of the portion of the feature within the offset region.
[0059] The multi-scale SL apparatus 100 determines the size of the
pinhole for each of the one or more apertures of the dynamic
aperture 106. The size of the pinhole for each of the one or more
apertures may be pre-configured or user-inputted. The multi-scale
SL apparatus 100 calculates an offset for each aperture. The
multi-scale SL apparatus 100 may order the different apertures with
differently sized pinholes from smallest to largest to determine
the one or more offsets from the contour of the part 122.
[0060] For example, the multi-scale SL apparatus 100 identifies the
aperture with the smallest pinhole, i.e., the smallest aperture
size, and sets a smallest offset a distance from the contour of the
part 122. The first distance may be approximately the size of the
smallest aperture size. This forms a boundary portion between the
contour of the part 122 and the smallest offset. The multi-scale SL
apparatus 100 reserves this boundary portion to use a small-scale
aperture that has a small-scale pinhole to form a small-scale laser
beam to ensure that small or highly detailed features of the
boundary portion are fabricated with a high resolution.
[0061] After determining the smallest offset, the multi-scale SL
apparatus 100 determines the next offset based on the ordering of
the apertures. The next offset is offset relative to the offset for
the previous aperture, e.g., the previous aperture with the
previous smaller sized pinhole and based on the size of the next
aperture in the ordering. The multi-scale SL apparatus 100 repeats
this process of determining the offset until the last remaining
aperture, which may be the aperture with the largest sized pinhole
and which may be used to form the interior portion. The last
aperture, such as the aperture with the largest sized pinhole, may
be used to form the remaining portion, i.e., the interior portion
of the part 122, after all the other offsets, for example.
[0062] For example, if there are 3 apertures and the smallest
aperture size is approximately 50 .mu.m, the first offset is
approximately 50 .mu.m from the contour of the part 122. If next
smallest apertures size, e.g., the medium aperture size, is
approximately 100 .mu.m, the second offset is approximately 100 p.m
from the first offset and approximately 150 .mu.m from the contour
of the part 122. Lastly, the multi-scale SL apparatus 100 uses the
largest aperture size, which may be approximately 200 .mu.m to 300
.mu.m, for the remaining portion that is farthest inward from the
contour of the part 122, i.e., the interior portion.
[0063] The multi-scale SL apparatus 100 may divide one or more of
the multiple large layers into a boundary portion and an interior
portion based on the one or more offsets (608). The multi-scale SL
apparatus 100 may determine that a portion between the contour of
the part 122 and the one or more offsets is the boundary portion
and determine that the remaining portion that is inward of the one
or more offsets is the interior portion. By using the largest
aperture size to fabricate the interior portion and the other
aperture sizes to fabricate the boundary portion, the multi-scale
SL apparatus 100 optimizes resolution and/or speed along the XY
plane.
[0064] The multi-scale SL apparatus 100 may slice the boundary
portion of each of the multiple large layers into multiple smaller
layers (610). The multiple smaller layers may be of any number of
layers with differing thicknesses. The multiple smaller layers may
have a small thickness, which may be smaller in thickness than the
large thickness of the large layer. A smaller layer may have a
thickness of approximately 20 .mu.m, for example. In some
implementations, the multi-scale SL apparatus 100 may slice the
boundary portion of each of the multiple large layers into multiple
medium layers with a medium thickness and slice each of the
multiple medium layers into the multiple smaller layers. The medium
thickness may be greater than the small thickness but less than the
large thickness. The multi-scale SL apparatus 100 may use any
number of slices to optimize the resolution and/or the speed of the
fabrication.
[0065] When the multi-scale SL apparatus 100 slices the boundary
portion of each of the multiple larger layers into multiple smaller
layers, the multi-scale SL apparatus 100 provides for higher
resolution along the boundary portion, since the layers within the
boundary portion are of a smaller thickness. Whereas, when the
multi-scale SL apparatus 100 slices the interior portion into
multiple large layers, the multi-scale SL apparatus 100 provides
for faster fabrication speed(s). Since only the boundary portion
utilizes the smaller layers, this saves a significant amount of
printing time since the inner portion is filled using the
large-scale laser beam and larger layers. FIG. 9 shows a large
layer 900 of the multiple large layers of a part 122 and the
corresponding interior portion 902 and boundary portion 904 of the
large layer 900. The boundary portion 904 is divided into multiple
small layers 906a-e.
[0066] Instead of dividing the large layer into the boundary
portion and interior portion and slicing the boundary portion into
multiple small layers, in some implementations, the multi-scale SL
apparatus 100 may slice each of the multiple large layers that form
the part 122 into multiple small layers, and then, divide each of
the multiple small layers into a boundary portion and an interior
portion based on the one or more offsets. Similarly, this provides
for a higher resolution along the boundary portion, since the
layers within the boundary portion are of a smaller thickness. And,
since the multi-scale SL apparatus 100 may use a large-scale laser
beam to fabricate the interior portion, which is a common region
among the multiple smaller layers, this provides for a faster
fabrication speed.
[0067] The multi-scale SL apparatus 100 generates one or more
toolpaths based on the sliced digital model including the one or
more offsets and the thickness of each layer of the digital model
(612). The multi-scale SL apparatus 100 may generate a toolpath for
each aperture of the dynamic aperture 106 that is used to form
layers within portions among the one or more offsets.
[0068] For example, the multi-scale SL apparatus 100 may generate a
toolpath for the small-scale aperture that is used to fabricate the
boundary portion within the smallest offset, which is closest to
the contours of the part 122, and has a small layer thickness. The
multi-scale SL apparatus 100 may generate a toolpath for each of
the other apertures that are used to fabricate the boundary portion
within the other offsets. And, the multi-scale SL apparatus 100 may
generate a last toolpath for the large-scale aperture that is used
to fabricate the interior portion, which is the most inward and
farthest from the contours of the part, and has a large layer
thickness.
[0069] The multi-scale SL apparatus 100 may generate a toolpath for
each layer of each offset within the boundary portion and for the
interior portion of the part 122. The multi-scale SL apparatus 100
may associate the corresponding aperture of a particular size with
a layer of a particular thickness within an offset from the
contours of the part 122. The multi-scale SL apparatus 100 may
associate any number of aperture sizes with any number of
thicknesses. For example, a small-scale aperture size may be
associated with a small-scale offset and a small layer thickness, a
medium-scale aperture size may be associated with a medium-scale
offset and a small layer thickness, and a large-scale aperture size
may be associated with a large-scale offset and a large layer
thickness. In another example, a small-scale aperture size may be
associated with a small-scale offset and a small layer thickness, a
medium-scale aperture size may be associated with a medium-scale
offset and a medium layer thickness, and a large-scale aperture
size may be associated with a large-scale offset and a large layer
thickness. In some implementations, two or more toolpaths may
overlap or have an overlapping portion to ensure that the toolpaths
are blended together and/or a buffer region to prevent any empty
regions between the toolpaths.
[0070] FIG. 8 shows a table that compares different
stereolithography apparatuses and/or processes across different
metrics. The various apparatuses and/or processes included
laser-based SLA (LSL), projection-based micro SLA (PuSL), two
photon polymerization (TPP), continuous interface liquid production
(CLIP) and large area projection-based micro SLA (LaPuSL). The
comparison is done across five major fabrication metrics including
part size, feature resolution, part-size-to-feature-size ratio,
fabrication speed and cost. As shown in FIG. 8, the conventional SL
processes face trade-offs among fabrication speed, resolution,
scalability and cost. However, the multi-scale SL apparatus 100
optimizes the resolution, speed and cost. The multi-scale SL
apparatus 100 uses the multi-scale laser beams in the XY plane and
multi-scale layer thickness in the Z direction to optimize the
resolution, speed and cost.
[0071] Exemplary embodiments of the invention have been disclosed
in an illustrative style. Accordingly, the terminology employed
throughout should be read in a non-limiting manner. Although minor
modifications to the teachings herein will occur to those well
versed in the art, it shall be understood that what is intended to
be circumscribed within the scope of the patent warranted hereon
are all such embodiments that reasonably fall within the scope of
the advancement to the art hereby contributed, and that that scope
shall not be restricted, except in light of the appended claims and
their equivalents.
* * * * *