U.S. patent application number 14/567010 was filed with the patent office on 2016-06-16 for forming sacrificial structures using phase-change materials that sublimate.
The applicant listed for this patent is Palo Alto Research Center Incorporation. Invention is credited to Bing R. Hsieh, Tse Nga Ng, Steven E. Ready.
Application Number | 20160167089 14/567010 |
Document ID | / |
Family ID | 56110234 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160167089 |
Kind Code |
A1 |
Ng; Tse Nga ; et
al. |
June 16, 2016 |
FORMING SACRIFICIAL STRUCTURES USING PHASE-CHANGE MATERIALS THAT
SUBLIMATE
Abstract
A structure can include a first layer of a polymer material and
a second layer of the polymer material on the first layer, the
first and second layers of the polymer material defining a hollow
space that was formed by way of a temporary sacrificial structure
that was made of a sublimable material.
Inventors: |
Ng; Tse Nga; (Sunnyvale,
CA) ; Hsieh; Bing R.; (Pleasanton, CA) ;
Ready; Steven E.; (Los Altos, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Palo Alto Research Center Incorporation |
Palo Alto |
CA |
US |
|
|
Family ID: |
56110234 |
Appl. No.: |
14/567010 |
Filed: |
December 11, 2014 |
Current U.S.
Class: |
428/319.3 ;
427/255.7 |
Current CPC
Class: |
B29C 64/118 20170801;
B29C 33/448 20130101; B29C 64/40 20170801; B33Y 10/00 20141201;
B29K 2075/00 20130101; B29C 64/106 20170801; B29C 64/112 20170801;
B29C 64/124 20170801 |
International
Class: |
B05D 7/00 20060101
B05D007/00 |
Claims
1. A structure, comprising: a first layer of a polymer material;
and a second layer of the polymer material on the first layer, the
first and second layers of the polymer material defining a hollow
space that was formed by way of a temporary sacrificial structure
that was made of a sublimable material.
2. The structure of claim 1, wherein the sublimable material
includes cyclododecane and/or other phase-change composites.
3. The structure of claim 1, wherein the sacrificial structure has
been removed by way of sublimation.
4. The structure of claim 3, wherein the sublimation was performed
at a pressure of approximately 1 millitorr.
5. The structure of claim 3, wherein the sublimation was performed
at a temperature less than 160 degrees C.
6. The structure of claim 5, wherein the temperature was
approximately 55 degrees C.
7. The structure of claim 1, wherein the polymer material is an
ultraviolet-curable polymer material.
8. The structure of claim 1, wherein the hollow space is a cavity
or a channel.
9. The structure of claim 1, the first and second layers of the
polymer material defining another hollow space that was formed by
way of another temporary sacrificial structure that was made of the
sublimable material.
10. The structure of claim 1, further comprising a third layer of
the polymer material on the second layer, the third and second
layers of the polymer material defining another hollow space that
was formed by way of another temporary sacrificial structure that
was made of the sublimable material.
11. A method, comprising: depositing a first layer of a polymer
material; depositing a first amount of sublimable material on the
first layer of the polymer material to form a first sacrificial
structure; depositing a second layer of the polymer material on the
first amount of sublimable material and first layer of the polymer
material; and removing the sublimable material to form a first
hollow space defined by the first and second layers of the polymer
material.
12. The method of claim 11, wherein the removing includes
performing sublimation.
13. The method of claim 12, wherein the sublimation includes
heating at a certain temperature and at a certain pressure.
14. The method of claim 13, wherein the certain pressure is
approximately 1 millitorr.
15. The method of claim 13, wherein the certain temperature is less
than 160 degrees C.
16. The method of claim 15, wherein the certain temperature is
approximately 55 degrees C.
17. The method of claim 11, wherein the sublimable material
includes cyclododecane and/or other phase-change composites.
18. The method of claim 11, wherein the hollow space is a cavity or
a channel.
19. The method of claim 11, further comprising to build multiple
layered structures. depositing a second amount of sublimable
material on the first layer of the polymer material to form a
second sacrificial structure; depositing a third layer of the
polymer material on the second amount of sublimable material and
first layer of the polymer material; and removing the sublimable
material to form a second hollow space defined by the first and
third layers of the polymer material.
20. The method of claim 11, further comprising to build multiple
layered structures. depositing a second amount of sublimable
material on the second layer of the polymer material to form a
second sacrificial structure; depositing a third layer of the
polymer material on the second amount of sublimable material and
second layer of the polymer material; and removing the second
amount of sublimable material to form a second hollow space defined
by the second and third layers of the polymer material.
Description
TECHNICAL FIELD
[0001] The disclosed technology relates generally to the field of
forming sacrificial structures and, more particularly, to forming
sacrificial structures using phase-change materials that
sublimate.
BACKGROUND
[0002] In today's layer-by-layer printing techniques for forming
three-dimensional (3D) structures, sacrificial materials are
generally needed to form temporary support structures that are
later removed to leave behind voids or channels. Typical
sacrificial materials include polymers or waxes that are
dissolvable by solvents or can be decomposed by high-temperature
annealing. However, such removal procedures can disadvantageously
cause problems arising from stiction (e.g., static friction that
needs to be overcome to enable relative motion of stationary
objects in contact) resulting from capillary force during washing.
These removal procedures may also undesirably cause decomposition
residues to be left behind.
SUMMARY
[0003] According to aspects illustrated herein, there is provided a
structure comprising a first layer of a polymer material and a
second layer of the polymer material on the first layer, the first
and second layers of the polymer material defining a hollow space
that was formed by way of a temporary sacrificial structure that
was made of a sublimable material such as cyclododecane and then
removed. This process may be repeated any of a number of times,
e.g., to build up layered structures having multiple hollow
spaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a block diagram illustrating the depositing and
crosslinking of a photonic curable polymer material, such as
UV-curable polymers and composites, in accordance with certain
embodiments of the disclosed technology.
[0005] FIG. 2 is a block diagram illustrating the depositing of a
sacrificial material (e.g., cyclododecane) from its liquid state on
top of the layer of UV-crosslinked polymer material illustrated by
FIG. 1 in accordance with certain embodiments of the disclosed
technology.
[0006] FIG. 3 is a block diagram illustrating the depositing of a
second layer of UV-curable polymer material to cover the
sacrificial structure on the first layer of UV-curable polymer
material as illustrated by FIG. 2 in accordance with certain
embodiments of the disclosed technology.
[0007] FIG. 4 is a block diagram illustrating a three-dimensional
(3D) structure having a channel or hollow space defined therein in
accordance with certain embodiments of the disclosed
technology.
[0008] FIG. 5 is a graphical representation illustrating an example
of the viscosity versus shear rate data for cyclododecane.
[0009] FIG. 6 is a flowchart illustrating an example of a method of
creating a structure in accordance with certain embodiments of the
disclosed technology.
DETAILED DESCRIPTION
[0010] Embodiments of the disclosed technology generally pertain to
the use of a sacrificial material that can be removed by
sublimation, accelerated by heat and/or a low pressure environment.
Such embodiments generally do not rely on the use of solvents to
wash off the sacrificial materials, thus simplifying the removal
process as compared to the decomposition of polymers that requires
high temperature burning, for example,
[0011] Certain embodiments of the disclosed technology generally
include the use of materials that can be sublimated at low
temperature (e.g., less than 160 degrees C.) as the sacrificial
structures. Use of such materials may advantageously avoid the use
of a solvent or high temperature decomposition during the removal
process. Phase-change material may be deposited as a liquid, and
the liquid state may fill in empty spaces and subsequently solidify
to enable temporary planarization.
[0012] Certain embodiments of the disclosed technology may include
the use of cyclododecane, which is a hydrocarbon having a melting
point around 58-60 degrees C. and high vapor pressure that allows
sublimation thereof at low temperature. The phase-change material
may be heated to its liquid state for deposition, and then solidify
upon contacting a surface below its melting point.
[0013] As cyclododecane has high vapor pressure (e.g.,
approximately 10 Pa), it may typically be sublimated at room
temperature, though generally at slow rate. In certain embodiments,
material removal may be accelerated by heating the structure in a
low vacuum oven (e.g., 1 millitorr or mTorr) at a certain
temperature (e.g., approximately 55 degrees C.). In such
embodiments, the sacrificial cyclododecane may be sublimated within
minutes, depending on the volume of materials.
[0014] FIGS. 1-4 together illustrate an example in which a
sacrificial material is used with an ultraviolet (UV)-curable
polymer (e.g., polyurethane) to form a three-dimensional (3D)
structure having a cavity or hollow space therein in accordance
with certain embodiments of the disclosed technology.
[0015] FIG. 1 is a block diagram 100 illustrating the depositing
and crosslinking of a UV-curable polymer material and/or other
composites 102.
[0016] FIG. 2 is a block diagram 200 illustrating the depositing of
a sacrificial ink or other suitable material 204 (e.g.,
cyclododecane) from its liquid state on top of the layer of
UV-crosslinked polymer material 102 illustrated by FIG. 1. The
sacrificial material 204 then solidifies into a sacrificial
structure.
[0017] FIG. 3 is a block diagram 300 illustrating the depositing of
a second layer of UV-curable polymer material 306 to cover the
sacrificial structure 204 on the first layer of UV-curable polymer
material 102 as illustrated by FIG. 2. This second layer of
UV-curable polymer material 306 may be subsequently
cross-linked.
[0018] The entire structure illustrated by FIG. 3 may be placed in
a vacuum oven at a certain temperature (e.g., 55 degrees C.) and at
a certain pressure (e.g., approximately 1 millitorr or mTorr). The
sacrificial material 204 may then be removed (e.g., by
sublimation), leaving behind a structure having a channel 408
defined therein as illustrated by the block diagram 400 of FIG.
4.
[0019] The sacrificial ink used in the example illustrated by FIGS.
1-4 may be composed of neat cyclododecane with no solvent, but the
cyclododecane [or other sublimable material(s)] may also be mixed
with an organic solvent, such as toluene or acetone, for example,
in order to change the viscosity for different deposition methods.
While mixing solvent with the sacrificial material may result in a
structural shrinkage issue when the solvent evaporates, this
potential issue may be addressed by programming the printing tool
to compensate for the dimensional change.
[0020] FIG. 5 is a graphical representation 500 illustrating an
example of the viscosity versus shear rate data for
cyclododecane.
[0021] FIG. 6 is a flowchart illustrating an example of a method
600 of creating a structure in accordance with certain embodiments
of the disclosed technology.
[0022] At 602, a first layer of a polymer material, such as the
ultraviolet (UV)-curable polymer material 102 illustrated by FIGS.
1-4, may be deposited, e.g., onto a substrate. The polymer material
may also be crosslinked.
[0023] At 604, a sublimable material, such as the sacrificial
material 204 illustrated by FIGS. 2 and 3, may be deposited onto
the first layer of the polymer material. The sublimable material,
such as cyclododecane, may be deposited from its liquid state and
subsequently solidify into a sacrificial structure.
[0024] At 606, a second layer of the polymer material, such as the
UV-curable polymer material 306 illustrated by FIGS. 3 and 4, may
be deposited to cover the sacrificial structure and first layer
polymer material. This second layer of polymer material may also be
subsequently cross-linked. The process from 602 to 606 may be
repeated any of a number of times, e.g., to build multiple-layered
structures having multiple hollow spaces defined therein.
[0025] At 608, the sublimable material may be removed, e.g., by a
sublimation process, to form a hollow space, such as the channel
408 illustrated by FIG. 4, defined by the first and second layers
of polymer material. For example, the entire structure may be
placed in a vacuum oven at a certain temperature (e.g.,
approximately 120 degrees C.) and at a certain pressure (e.g.,
approximately 1 millitorr or mTorr). The process from 602 to 608
may be repeated any of a number of times, e.g., to build
multiple-layered structures having multiple hollow spaces defined
therein.
[0026] Materials having different vapor pressure may be chosen to
form sacrificial structures that are sequentially removed. For
example, if a certain structural part is to be released before
another, the first part may be patterned by a sacrificial material
having a certain vapor pressure and the second part to be released
may be patterned using a sacrificial material having a vapor
pressure that is lower than that of the first sacrificial
material.
[0027] In addition to patterning a sacrificial material in a
layer-by-layer manner, the material may also be deposited into a
well structure in order to fill in the empty space and hence
provide temporary structural support.
[0028] It will be appreciated that several of the above-disclosed
and other features and functions, or alternatives thereof, may be
desirably combined into many other different systems or
applications. Also that various presently unforeseen or
unanticipated alternatives, modifications, variations, or
improvements therein may be subsequently made by those skilled in
the art which are also intended to be encompassed by the following
claims.
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