U.S. patent application number 14/189819 was filed with the patent office on 2015-06-11 for object of additive manufacture with encoded predicted shape change and method of manufacturing same.
This patent application is currently assigned to Stratasys Ltd.. The applicant listed for this patent is Massachusetts Institute of Technology, Stratasys Ltd.. Invention is credited to Daniel Dikovsky, Shai Hirsch, Skylar J.E. Tibbits.
Application Number | 20150158244 14/189819 |
Document ID | / |
Family ID | 53270260 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150158244 |
Kind Code |
A1 |
Tibbits; Skylar J.E. ; et
al. |
June 11, 2015 |
Object Of Additive Manufacture With Encoded Predicted Shape Change
And Method Of Manufacturing Same
Abstract
The combination of 3D printing technology plus the additional
dimension of transformation over time of the printed object is
referred to herein as 4D printing technology. Particular
arrangements of the additive manufacturing material(s) used in the
3D printing process can create a printed 3D object that transforms
over time from a first, printed shape to a second, predetermined
shape.
Inventors: |
Tibbits; Skylar J.E.;
(Boston, MA) ; Dikovsky; Daniel; (Rehovot, IL)
; Hirsch; Shai; (Rehovot, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stratasys Ltd.
Massachusetts Institute of Technology |
Rehovot
Cambridge |
MA |
IL
US |
|
|
Assignee: |
Stratasys Ltd.
Rehovot
MA
Massachusetts Institute of Technology
Cambridge
|
Family ID: |
53270260 |
Appl. No.: |
14/189819 |
Filed: |
February 25, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61930521 |
Jan 23, 2014 |
|
|
|
61912056 |
Dec 5, 2013 |
|
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Current U.S.
Class: |
428/516 ;
264/230; 264/255; 264/479; 403/119; 403/164; 403/52; 425/166;
522/170; 522/181; 522/182; 522/183; 524/553; 524/558; 524/559;
524/612; 526/282; 526/313; 526/320; 528/421 |
Current CPC
Class: |
B29C 69/025 20130101;
B33Y 70/00 20141201; B33Y 50/02 20141201; B29C 64/386 20170801;
Y10T 403/32975 20150115; Y10T 403/32 20150115; B33Y 10/00 20141201;
B33Y 80/00 20141201; B29C 61/003 20130101; Y10T 403/32606 20150115;
B29K 2033/04 20130101; C08F 220/20 20130101; B29K 2071/02 20130101;
Y10T 428/31913 20150401; C08F 220/20 20130101; C08F 222/1067
20200201; C08F 220/20 20130101; C08F 222/1067 20200201 |
International
Class: |
B29C 61/00 20060101
B29C061/00; C08F 20/28 20060101 C08F020/28; C08G 65/26 20060101
C08G065/26; C08F 20/30 20060101 C08F020/30; C08L 33/08 20060101
C08L033/08; C08F 20/18 20060101 C08F020/18; C08L 33/14 20060101
C08L033/14; C08L 71/02 20060101 C08L071/02; C08L 35/02 20060101
C08L035/02; B29C 67/00 20060101 B29C067/00; C08F 22/10 20060101
C08F022/10 |
Claims
1. An object, comprising: an additive manufacturing material, the
additive manufacturing material having a response to an external
stimulus and being configured to cause a predicted transformation
of the object from a first manufactured shape to a second
manufactured shape in response to the external stimulus, the
external stimulus being non-biasing with respect to the predicted
transformation from the first manufactured shape to the second
manufactured shape.
2. The object of claim 1, wherein the external stimulus is a
temperature change.
3. The object of claim 2, wherein the additive manufacturing
material has a glass transition temperature of approximately
0.degree. C. to approximately 150.degree. C.
4. The object of claim 3, wherein the additive manufacturing
material has a glass transition temperature of approximately
75.degree. C. to approximately 90.degree. C.
5. The object of claim 1, wherein the additive manufacturing
material is a first additive manufacturing material and wherein the
object has a second additive manufacturing material arranged
relative to the first additive manufacturing material to enable the
predicted transformation of the object from the first manufactured
shape to the second manufactured shape in response to the external
stimulus.
6. The object of claim 5, wherein the second additive manufacturing
material has a second response to either the first external
stimulus or to a second external stimulus to enable a corresponding
second predicted transformation of the object to a third
manufactured shape.
7. The object of claim 5, wherein the first and second additive
manufacturing materials compose the entire object.
8. The object of claim 5, further comprising a third additive
manufacturing material arranged relative to the first or second
additive manufacturing materials, or both, and having a third
response to the first external stimulus, the second external
stimulus, or a third external stimulus to enable a corresponding
third predicted transformation of the object to a fourth
manufactured shape.
9. The object of claim 8, wherein the first, second, and third
additive manufacturing materials compose the entire object.
10. The object of claim 8, wherein the third additive manufacturing
material has a third response that modifies the properties of one
or more of the first or second additive manufacturing
materials.
11. The object of claim 10, wherein the property modified is the
stiffness of one or more of the first and second additive
manufacturing materials.
12. The object of claim 5, wherein the external stimulus is
selected from the group consisting of a solvent, temperature
change, electromagnetic energy, and pressure change.
13. The object of claim 5, wherein the first and second additive
manufacturing materials are arranged to form a joint of the
object.
14. The object of claim 13, wherein the joint is a means for
effecting linear or rotational displacement of a first member of
the object relative to a second member of the object.
15. The object of claim 14, wherein the joint has at least one
cylindrical disc.
16. The object of claim 14, wherein the joint has at least one
rectangular member.
17. The object of claim 14, wherein each of the first and second
additive manufacturing materials composing the joint has a
three-dimensional structure.
18. The object of claim 14, wherein the joint is a means for
curling.
19. The object of claim 14, wherein the joint is a means for
folding.
20. The object of claim 14, wherein the joint is a means for linear
elongation.
21. The object of claim 14, wherein the joint is a means for
decreasing the size of a hole.
22. The object of claim 14, wherein the joint is a means for
forming a curved crease.
23. The object of claim 14, wherein the joint is a means for linear
expansion.
24. The object of claim 5, wherein the external stimulus is a
solvent.
25. The object of claim 24, wherein the first additive
manufacturing material is more hydrophilic than the second additive
manufacturing material.
26. The object of claim 25, wherein the first additive
manufacturing material comprises a polymerized formulation
comprising one or more of hydrophilic acrylic monomers and
oligomers.
27. The object of claim 26, wherein the first additive
manufacturing material is comprises a polymerized formulation
comprising hydroxyethyl acrylate or poly(ethylene) glycol.
28. The object of claim 24, wherein the second additive
manufacturing material comprises a polymerized formulation
comprising one or more of hydrophobic acrylic monomers and
oligomers.
29. The object of claim 28, wherein the second additive
manufacturing material comprises a polymerized formulation
comprising monomers of one or more of phenoxy ethyl acrylate,
trimethylol propane triacrylate, and isobornyl acrylate.
30. The object of claim 24, wherein one or more of the first and
second additive manufacturing materials comprises a polymerization
formulation that comprises one or more of a photoinitiator, surface
active agent, stabilizer, and inhibitor.
31. A method for additive manufacturing of an object, the method
comprising: dispensing an additive manufacturing material having a
response to an external stimulus, the additive manufacturing
material being configured to cause a predicted transformation of
the object from a first manufactured shape to a second manufactured
shape in response to the external stimulus, the external stimulus
being non-biasing with respect to the predicted transformation from
the first manufactured shape to the second manufactured shape.
32. The method of claim 31, wherein the additive manufacturing
material has a glass transition temperature of approximately
0.degree. C. to approximately 150.degree. C.
33. The method of claim 32, wherein the first additive
manufacturing material has a glass transition temperature of
approximately 75.degree. C. to approximately 90.degree. C.
34. The method of claim 32, further comprising exposing the object
to an external stimulus, wherein the external stimulus is a
temperature change.
35. The method of claim 31, wherein the additive manufacturing
material is a first additive manufacturing material and further
comprising dispensing a second additive manufacturing material
arranged relative to the first additive manufacturing material to
enable the predicted transformation of the object from the first
manufactured shape to the second manufactured shape in response to
the external stimulus.
36. The method of claim 35, wherein the external stimulus is a
first external stimulus and wherein the second additive
manufacturing material has a second response to either the first
external stimulus or to a second external stimulus to enable a
corresponding second predicted transformation of the object to a
third manufactured shape.
37. The method of claim 36, wherein the first and second additive
manufacturing materials compose the entire object.
38. The method of claim 36, further comprising dispensing a third
additive manufacturing material arranged relative to the first or
second additive manufacturing materials, or both, and having a
third response to the first external stimulus, the second external
stimulus, or a third external stimulus to enable a corresponding
third predicted transformation of the object to a fourth
manufactured shape.
39. The method of claim 38, wherein the first, second, and third
additive manufacturing materials compose the entire object.
40. The method of claim 38, wherein the third response of the third
additive manufacturing material modifies the properties of one or
more of the first or second additive manufacturing materials.
41. The method of claim 40, wherein the property modified is the
stiffness of one or more of the first and second additive
manufacturing materials.
42. The method of claim 35, wherein the first and second additive
manufacturing materials are arranged to form a joint of the
object.
43. The method of claim 42, wherein the joint is a means for
effecting linear or rotational displacement of a first member of
the object relative to a second member of the object.
44. The method of claim 42 wherein the joint has at least one
cylindrical disc.
45. The method of claim 42, wherein the joint has at least one
rectangular member.
46. The method of claim 42, wherein each of the first and second
additive manufacturing materials composing the joint has a
three-dimensional structure.
47. The method of claim 42, wherein the joint is a means for
curling.
48. The method of claim 42, wherein the joint is a means for
folding.
49. The method of claim 42, wherein the joint is a means for linear
elongation.
50. The method of claim 42, wherein the joint is a means for
decreasing the size of a hole.
51. The method of claim 42, wherein the joint is a means for
forming a curved crease.
52. The method of claim 42, wherein the joint is a means for linear
expansion.
53. The method of claim 35, wherein the first additive
manufacturing material is more hydrophilic than the second
material.
54. The method of claim 53, wherein the first additive
manufacturing material comprises a polymerized formulation
comprising one or more of hydrophilic acrylic monomers and
oligomers.
55. The method of claim 54, wherein the first additive
manufacturing material comprises a polymerized formulation
comprising hydroxyethyl acrylate or poly(ethylene) glycol.
56. The method of claim 35, wherein the second additive
manufacturing material comprises a polymerized formulation
comprising one or more of hydrophobic acrylic monomers and
oligomers.
57. The method of claim 56, wherein the second additive
manufacturing material comprises a polymerized formulation
comprising monomers of one or more of phenoxy ethyl acrylate,
trimethylol propane triacrylate, and isobornyl acrylate.
58. The method of claim 35, wherein one or more of the first and
second additive manufacturing materials a polymerized formulation
further comprising one or more of a photoinitiator, surface active
agent, stabilizer, and inhibitor.
59. The method of claim 31, further comprising exposing the object
to an external stimulus selected from the group consisting of a
solvent, temperature change, electromagnetic energy, and pressure
change.
60. The method of claim 59, wherein the external stimulus is a
polar solvent.
61. The method of claim 60, wherein the polar solvent is selected
from the group consisting of water, an alcohol, and combinations
thereof.
62. The method of claim 59, wherein exposing the object to an
external stimulus causes one or more of curling, folding,
stretching, shrinking, and curved creasing.
63. A non-transient computer readable medium having stored thereon
a sequence of instructions that, when executed by a processor,
causes an apparatus to: access a database that includes first
parameters of additive manufacturing materials; access the database
that includes second parameters for arranging one or more additive
manufacturing materials relative to each other to form at least a
portion of an object having a first manufactured shape in an
absence of an external stimulus and having a second, predicted
manufactured shape in a presence of, or following exposure to, an
external stimulus; and calculate, as a function of the first and
second parameters, a sequence of machine-controllable instructions
that, when provided to a machine, programs the machine to produce
the object in the first manufactured shape.
64. The non-transient computer readable medium of claim 63, wherein
the database further includes parameters of an environment in which
the object will be employed, and wherein the sequence of
instructions further causes the apparatus to calculate
machine-controllable instructions as a function of the environment
or adjust the previously calculated machine-controllable
instructions as a function of the environment.
65. The non-transient computer readable medium of claim 63, wherein
the external stimulus comprises one or more of a solvent,
temperature change, electromagnetic energy, and pressure
change.
66. The non-transient computer readable medium of claim 63, wherein
the machine-controllable instructions cause the apparatus to
dispense a first additive manufacturing material.
67. The non-transient computer readable medium of claim 66, wherein
the machine-controllable instructions cause the apparatus to
dispense a second additive manufacturing material in an arrangement
relative to first additive manufacturing material to enable a
predicted transformation of the object from a first manufactured
shape to a second manufactured shape in response to the first
external stimulus.
68. The non-transient computer readable medium of claim 63, wherein
the external stimulus is a first external stimulus and the
predicted transformation is a first predicted transformation and
further comprising a third additive manufacturing material arranged
relative to the first or second additive manufacturing materials,
or both, wherein the third additive manufacturing material has a
third response to the first external stimulus or a second external
stimulus to enable a corresponding second predicted transformation
of the shape of the object in response to the first or second
external stimulus.
69. The non-transient computer readable medium of claim 63, wherein
the database includes a library of joints.
70. The non-transient computer readable medium of claim 69, wherein
the library of joints includes one or more of a curling joint, a
folding joint, a linear elongation joint, a joint that decreases
the size of a hole, a curved-crease joint, and a linear expansion
joint.
Description
RELATED APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/930,521, filed on Jan. 23, 2014. This
application also claims the benefit of U.S. Provisional Application
No. 61/912,056, filed on Dec. 5, 2013. The entire teachings of the
above applications are incorporated herein by reference.
COMMON OWNERSHIP UNDER JOINT RESEARCH AGREEMENT 35 U.S.C.
102(c)
[0002] The subject matter disclosed in this application was
developed, and the claimed invention was made by, or on behalf of,
one or more parties to a joint Research Agreement that was in
effect on or before the effective filing date of the claimed
invention. The parties to the Joint Research Agreement are the
Massachusetts Institute of Technology, located in Cambridge, Mass.,
USA; and Stratasys Ltd., an Israeli company located at 2 Holzman
Street, Rehovot, Israel 76124, and Stratasys, Inc., a Delaware
corporation located at 7665 Commerce Way, Eden Prairie, Minn. 55344
(collectively, "Stratasys").
BACKGROUND OF THE INVENTION
[0003] Traditional manufacturing typically involves molded
production of parts and other components having a fixed shape, and
those individual components are frequently assembled into more
complex structures. The process is often expensive and can involve
a significant amount of manual labor, and molds used in the
production are expensive to manufacture and have singular design
structure.
[0004] Three-dimensional (3D) printing has been used to create
static objects and other stable structures, such as prototypes,
products, and molds. Three dimensional printers can convert a 3D
image, which is typically created with computer-aided design (CAD)
software, into a 3D object through the layerwise addition of
material. For this reason, 3D printing has become relatively
synonymous with the term "additive manufacturing." In contrast,
"subtractive manufacturing" refers to creating an object by cutting
or machining away material to create a desired shape.
SUMMARY OF THE INVENTION
[0005] Existing 3D printing technologies hold a promise of an
ability to mass-produce customized components by substantially
reducing the time and materials necessary, which can consequently
increase efficiency. However, in some cases existing technology may
still require additional processes, for example labor-intensive
sorting and assembly of the 3D printed components in order to
arrive at a desired final product.
[0006] Embodiments described herein provide another dimension to 3D
printing technology. Particular arrangements of the additive
manufacturing materials used in the 3D printing process can create
a printed 3D object that transforms over time from a first, printed
shape to a second, predetermined shape. Therefore, the combination
of 3D printing technology plus the additional dimension of
transformation over time of the printed object is referred to
herein as 4D printing technology. This 4D printing technology in
some cases provides a number of benefits over 3D printing
technology. In particular, some physical objects made through a 3D
printing process that might otherwise have necessitated assembly or
other post-processing of printed parts can be rapidly manufactured
and assembled without requiring post-printing assembly, thereby
reducing the time and costs associated with assembly. Objects can
be printed in a first shape and transformed to a second,
predetermined shape at a later time. For example, the objects can
be printed and transported in a first shape that is flat, and then
expanded to a second shape at a later time, such as upon arrival at
a customer's location. This can permit more efficient shipping
because the first (i.e., shipping) shape is more flat and requires
a smaller shipping volume. Printing flat objects also requires
significantly less printing time, thereby also reducing the overall
fabrication costs.
[0007] Objects can be designed by reference to a second shape, and
computer software loadable from a non-transient computer-readable
medium can be used to calculate the first shape in which an object
is printed for subsequent transformation to at least one second
shape.
[0008] Disclosed herein is an object. The object can be made from
an additive manufacturing material. The additive manufacturing
material can have a response to an external stimulus and be
configured to cause a predicted transformation of the object from a
first manufactured shape to a second manufactured shape in response
to the external stimulus. The external stimulus can be non-biasing
with respect to the predicted transformation from the first
manufactured shape to the second manufactured shape.
[0009] The external stimulus can be a temperature change. The
additive manufacturing material can have a glass transition
temperature of approximately 0.degree. C. to approximately
150.degree. C., or approximately 75.degree. C. to approximately
90.degree. C.
[0010] The additive manufacturing material can be a first additive
manufacturing material, and the object can have a second additive
manufacturing material arranged relative to the first additive
manufacturing material to enable the predicted transformation of
the object from the first manufactured shape to the second
manufactured shape in response to the external stimulus. The second
additive manufacturing material can have a second response to
either the first external stimulus or to a second external stimulus
to enable a corresponding second predicted transformation of the
object to a third manufactured shape. The first and second additive
manufacturing materials can compose the entire object.
[0011] The object can further include a third additive
manufacturing material arranged relative to the first or second
additive manufacturing materials, or both, and can have a third
response to the first external stimulus, the second external
stimulus, or a third external stimulus to enable a corresponding
third predicted transformation of the object to a fourth
manufactured shape. The first, second, and third additive
manufacturing materials can compose the entire object. The third
additive manufacturing material can have a third response that
modifies the properties of one or more of the first or second
additive manufacturing materials. The property modified can be the
stiffness of one or more of the first and second additive
manufacturing materials.
[0012] The external stimulus can be selected from the group
consisting of a solvent, temperature change, electromagnetic
energy, and pressure change.
[0013] The first and second additive manufacturing materials can be
arranged to form a joint of the object. The joint can effect linear
or rotational displacement of a first member of the object relative
to a second member of the object. The joint can have at least one
cylindrical disc or at least one rectangular member. Each of the
first and second additive manufacturing materials composing the
joint can have a three-dimensional structure. The joint can curl,
fold, elongate linearly, decrease the size of a hole, form a curved
crease, or expand linearly.
[0014] The first external stimulus can be a solvent. The first
additive manufacturing material can be more hydrophilic than the
second additive manufacturing material. The first additive
manufacturing material can be formed of a polymerized formulation
that includes one or more of hydrophilic acrylic monomers and
oligomers. The first additive manufacturing material can be formed
of a polymerized formulation that includes hydroxyethyl acrylate or
poly(ethylene) glycol. The second additive manufacturing material
can be formed of a polymerized formulation that includes one or
more of hydrophobic acrylic monomers and oligomers. The second
additive manufacturing material can be formed of a polymerized
formulation that includes monomers of one or more of phenoxy ethyl
acrylate, trimethylol propane triacrylate, and isobornyl acrylate.
One or more of the first and second additive manufacturing
materials can be formed of a polymerized formulation that further
includes one or more of a photoinitiator, surface active agent,
stabilizer, and inhibitor.
[0015] Also disclosed herein is a method for additive manufacturing
of an object. The method can include dispensing an additive
manufacturing material having a response to an external stimulus.
The additive manufacturing material can be configured to cause a
predicted transformation of the object from a first manufactured
shape to a second manufactured shape in response to the external
stimulus. The external stimulus can be non-biasing with respect to
the predicted transformation from the first manufactured shape to
the second manufactured shape.
[0016] The first additive manufacturing material can have a glass
transition temperature of approximately 0.degree. C. to
approximately 150.degree. C., or approximately 75.degree. C. to
approximately 90.degree. C. The method can further include exposing
the object to an external stimulus, wherein the external stimulus
is a temperature change.
[0017] The additive manufacturing material can be a first additive
manufacturing material, and the method can further include
dispensing a second additive manufacturing material arranged
relative to the first additive manufacturing material to enable the
predicted transformation of the object from the first manufactured
shape to the second manufactured shape in response to the external
stimulus. The external stimulus can be a first external stimulus,
and the second additive manufacturing material can have a second
response to either the first external stimulus or to a second
external stimulus to enable a corresponding second predicted
transformation of the object to a third manufactured shape. The
first and second additive manufacturing materials can compose the
entire object.
[0018] The method can further include dispensing a third additive
manufacturing material arranged relative to the first or second
additive manufacturing materials, or both, and having a third
response to the first external stimulus, the second external
stimulus, or a third external stimulus to enable a corresponding
third predicted transformation of the object to a fourth
manufactured shape. The first, second, and third additive
manufacturing materials can compose the entire object. The third
response of the third additive manufacturing material can modify
the properties of one or more of the first or second additive
manufacturing materials. The property modified can be the stiffness
of one or more of the first and second additive manufacturing
materials.
[0019] The first and second additive manufacturing materials can be
arranged to form a joint of the object. The joint can effect linear
or rotational displacement of a first member of the object relative
to a second member of the object. The joint can have at least one
cylindrical disc or at least one rectangular member. Each of the
first and second additive manufacturing materials composing the
joint can have a three-dimensional structure. The joint can curl,
fold, elongate linearly, decrease the size of a hole, form a curved
crease, or expand linearly.
[0020] The first additive manufacturing material can be more
hydrophilic than the second material. The first additive
manufacturing material can be formed of a polymerized formulation
that includes one or more of hydrophilic acrylic monomers and
oligomers. The first additive manufacturing material can be formed
of a polymerized formulation that includes hydroxyethyl acrylate or
poly(ethylene) glycol. The second additive manufacturing material
can be formed of a polymerized formulation that includes one or
more of hydrophobic acrylic monomers and oligomers. The second
additive manufacturing material can be formed of a polymerized
formulation that includes monomers of one or more of phenoxy ethyl
acrylate, trimethylol propane triacrylate, and isobornyl acrylate.
One or more of the first and second additive manufacturing
materials can be formed of a polymerized formulation that further
includes one or more of a photoinitiator, surface active agent,
stabilizer, and inhibitor. The method can further include exposing
the object to an external stimulus selected from the group
consisting of a solvent, temperature change, electromagnetic
energy, and pressure change. The external stimulus can be a polar
solvent. The polar solvent can be selected from the group
consisting of water, an alcohol, and combinations thereof.
[0021] Exposing the object to an external stimulus can cause one or
more of curling, folding, stretching, shrinking, and curved
creasing.
[0022] Also disclosed herein is an object of additive manufacture
prepared according to the method described above. The method of
forming the object can include dispensing an additive manufacturing
material having a response to an external stimulus. The additive
manufacturing material can be configured to cause a predicted
transformation of the object from a first manufactured shape to a
second manufactured shape in response to the external stimulus. The
external stimulus can be non-biasing with respect to the predicted
transformation from the first manufactured shape to the second
manufactured shape.
[0023] The first additive manufacturing material can have a glass
transition temperature of approximately 0.degree. C. to
approximately 150.degree. C., or approximately 75.degree. C. to
approximately 90.degree. C. The method of forming the object can
further include exposing the object to an external stimulus,
wherein the external stimulus is a temperature change.
[0024] The additive manufacturing material can be a first additive
manufacturing material, and the method can further include
dispensing a second additive manufacturing material arranged
relative to the first additive manufacturing material to enable the
predicted transformation of the object from the first manufactured
shape to the second manufactured shape in response to the external
stimulus. The external stimulus can be a first external stimulus,
and the second additive manufacturing material can have a second
response to either the first external stimulus or to a second
external stimulus to enable a corresponding second predicted
transformation of the object to a third manufactured shape. The
first and second additive manufacturing materials can compose the
entire object.
[0025] The method of forming the object can further include
dispensing a third additive manufacturing material arranged
relative to the first or second additive manufacturing materials,
or both, and having a third response to the first external
stimulus, the second external stimulus, or a third external
stimulus to enable a corresponding third predicted transformation
of the object to a fourth manufactured shape. The first, second,
and third additive manufacturing materials can compose the entire
object. The third response of the third additive manufacturing
material can modify the properties of one or more of the first or
second additive manufacturing materials. The property modified can
be the stiffness of one or more of the first and second additive
manufacturing materials.
[0026] The first and second additive manufacturing materials can be
arranged to form a joint of the object. The joint can effect linear
or rotational displacement of a first member of the object relative
to a second member of the object. The joint can have at least one
cylindrical disc or at least one rectangular member. The joint can
curl, fold, elongate linearly, close a hole, form a curved crease,
or expand linearly.
[0027] The first additive manufacturing material can be more
hydrophilic than the second material. The first additive
manufacturing material can be formed of a polymerized formulation
that includes one or more of acrylic monomers and oligomers. The
first additive manufacturing material can be formed of a
polymerized formulation that includes hydroxyethyl acrylate. The
second additive manufacturing material can be formed of a
polymerized formulation that includes one or more of hydrophobic
acrylic monomers and oligomers. The second additive manufacturing
material can be formed of a polymerized formulation that includes
monomers of one or more of phenoxy ethyl acrylate, trimethylol
propane triacrylate, and isobornyl acrylate. One or more of the
first and second additive manufacturing materials can be formed of
a polymerized formulation that further includes one or more of a
photoinitiator, surface active agent, stabilizer, and inhibitor.
The method of forming the object can further include exposing the
object to an external stimulus selected from the group consisting
of a solvent, temperature change, electromagnetic energy, and
pressure change. The external stimulus can be a polar solvent. The
polar solvent can be selected from the group consisting of water,
an alcohol, and combinations thereof.
[0028] Exposing the object to an external stimulus can cause one or
more of curling, folding, stretching, shrinking, and curved
creasing.
[0029] Further disclosed herein is a non-transient computer
readable medium having stored thereon a sequence of instructions.
When executed by a processor, the sequence of instructions can
cause an apparatus to access a database that includes first
parameters of additive manufacturing materials, access the database
that includes second parameters for arranging one or more additive
manufacturing materials relative to each other to form at least a
portion of an object having a first manufactured shape in an
absence of an external stimulus and having a second, predicted
manufactured shape in a presence of, or following exposure to, an
external stimulus, and calculate, as a function of the first and
second parameters, a sequence of machine-controllable instructions
that, when provided to a machine, programs the machine to produce
the object in the first manufactured shape.
[0030] The database can further include parameters of an
environment in which the object will be employed. The sequence of
instructions can further cause the apparatus to calculate
machine-controllable instructions as a function of the environment
or adjust the previously calculated machine-controllable
instructions as a function of the environment.
[0031] The external stimulus can be one or more of a solvent,
temperature change, electromagnetic energy, and pressure change.
The machine-controllable instructions can cause the apparatus to
dispense a first additive manufacturing material. The
machine-controllable instructions can cause the apparatus to
dispense a second additive manufacturing material in an arrangement
relative to first additive manufacturing material to enable a
predicted transformation of the object from a first manufactured
shape to a second manufactured shape in response to the first
external stimulus.
[0032] The external stimulus can be a first external stimulus, and
the predicted transformation can be a first predicted
transformation and can further include a third additive
manufacturing material arranged relative to the first or second
additive manufacturing materials, or both, wherein the third
additive manufacturing material has a third response to the first
external stimulus or a second external stimulus to enable a
corresponding second predicted transformation of the shape of the
object in response to the first or second external stimulus.
[0033] The database can include a library of joints. The joints can
include one or more of a curling joint, a folding joint, a linear
elongation joint, a joint that decreases the size of a hole, a
curved-crease joint, and a linear expansion joint.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office
upon request and payment of the necessary fee.
[0035] The foregoing will be apparent from the following more
particular description of example embodiments of the invention, as
illustrated in the accompanying drawings in which like reference
characters refer to the same parts throughout the different views.
The drawings are not necessarily to scale, emphasis instead being
placed upon illustrating embodiments of the present invention.
[0036] FIG. 1 is a schematic representation of an arrangement of a
low swelling material and a high swelling material.
[0037] FIG. 2 is a schematic representation of an arrangement of a
low swelling material and a high swelling material that can form a
folding joint.
[0038] FIG. 3A is a computer generated model of an object formed by
an additive manufacturing process that can fold upon, or following,
exposure to an external stimulus.
[0039] FIG. 3B is a computer generated model of an object formed by
an additive manufacturing process that has folded after exposure to
an external stimulus.
[0040] FIG. 4A is a top view of a schematic representation of an
arrangement that can produce a folding transformation upon, or
following, exposure to an external stimulus.
[0041] FIG. 4B is a perspective view of a schematic representation
of an arrangement that can produce a folding transformation upon,
or following, exposure to an external stimulus.
[0042] FIG. 4C is a top view of a schematic representation of an
arrangement that has undergone a folding transformation after
exposure to an external stimulus.
[0043] FIG. 4D is a perspective view of a schematic representation
of an arrangement that has folded after exposure to an external
stimulus.
[0044] FIG. 4E is a top view of a schematic representation of an
arrangement having a plurality of joints that can fold to form a
Hilbert curve in the shape of a cube upon, or following, exposure
to an external stimulus.
[0045] FIG. 4F is a perspective view of a schematic representation
of an arrangement having a plurality of joints that has folded to
form a Hilbert curve in the shape of a cube after exposure to an
external stimulus.
[0046] FIG. 5 is a series of time-lapsed photographs showing a
transformation from a cylindrical object to a Hilbert curve in the
shape of a cube.
[0047] FIG. 6 is a table having four columns that: a) describe a
type of joint; b) provide a computer aided design (CAD) of the
joint; c) show an experimental representation of the joint after
exposure to an external stimulus; and d) illustrate a simulation
showing the predicted shape of the joint after exposure to an
external stimulus.
[0048] FIG. 7A is a top view of a schematic representation of an
arrangement of a generally cylindrical object having a series of
joints that can transform into an object that spells the letters
"MIT."
[0049] FIG. 7B is a side view of a schematic representation of an
arrangement of a generally cylindrical object having a series of
joints that can transform into an object that spells the letters
"MIT."
[0050] FIG. 7C is a schematic representation of an arrangement of a
generally cylindrical object having a series of joints that has
transformed into an object that spells the letters "MIT" after
exposure to an external stimulus.
[0051] FIG. 7D is a schematic illustrating an example joint that
can be used to spell letters upon, or following, exposure to an
external stimulus.
[0052] FIG. 7E is a schematic illustrating the example joint of
FIG. 7D after exposure to an external stimulus.
[0053] FIGS. 8A-8D are a series of time-lapsed photographs showing
a transformation from a generally cylindrical object to an object
that spells the letters "MIT."
[0054] FIG. 9A is a top view of a schematic representation of an
object that can transform into a cube having solid sides upon, or
following, exposure to an external stimulus.
[0055] FIG. 9B is perspective view of a schematic representation of
two panels having a joint that can fold upon, or following,
exposure to an external stimulus.
[0056] FIG. 9C is a side view of a schematic representation of two
panels having a joint that has folded upon exposure to an external
stimulus.
[0057] FIG. 9D is a perspective view of a schematic representation
of two panels having a joint that can fold upon, or following,
exposure to an external stimulus.
[0058] FIG. 9E is a side view of a schematic representation of two
panels having a joint that has folded after exposure to an external
stimulus.
[0059] FIG. 9F is a schematic representation of an object that has
transformed into a cube having solid sides after exposure to an
external stimulus.
[0060] FIG. 10A is a computer generated model of an object formed
by an additive manufacturing process that can transform into a cube
upon, or following, exposure to an external stimulus.
[0061] FIG. 10B is a computer generated model of an object formed
by an additive manufacturing process that has transformed into a
cube after exposure to an external stimulus.
[0062] FIGS. 11A-D are a series of time-lapsed photographs showing
a transformation of an object formed by an additive manufacturing
process into a cube upon, or following, exposure to an external
stimulus.
[0063] FIG. 12A is a schematic representation of an arrangement of
joints that can effect linear elongation.
[0064] FIG. 12B is a photograph of an object of additive
manufacture having an arrangement of joints that can effect linear
elongation.
[0065] FIG. 13A is a schematic representation of an object formed
by an additive manufacturing process that can undergo a curling
transformation upon, or following, exposure to an external
stimulus.
[0066] FIG. 13B is a simulation showing the predicted shape of the
object of FIG. 13A after exposure to an external stimulus.
[0067] FIG. 13C is a simulation showing the predicted shape of the
object of FIG. 13A after exposure to an external stimulus.
[0068] FIG. 13D is a series of photographs of an object formed by
an additive manufacturing process at various times before and after
exposure to an external stimulus. The photographs show an object
that can undergo an curling transformation upon, or following,
exposure to an external stimulus.
[0069] FIG. 14 is a block diagram of a 3D printing apparatus.
[0070] FIGS. 15A-B are schematic representations of an arrangement
of two low swelling materials and a high swelling material.
[0071] FIGS. 16A-C are schematic representations of an arrangement
of materials that can be used in a temperature-based system.
[0072] FIG. 17 is a schematic representation of an arrangement of
materials that can undergo a hole closing transformation.
[0073] FIG. 18A is four photographs of an object of additive
manufacture that can undergo a curved crease transformation.
[0074] FIG. 18B is three photographs of an object of additive
manufacture that can undergo a curved crease transformation.
[0075] FIG. 19 is three photographs of an object of additive
manufacture that can transform into an octahedron.
[0076] FIG. 20 is a series of photographs showing folding joints
having differentially-spaced cylindrical discs.
[0077] FIG. 21 is a series of photographs showing folding joints
having differentially-spaced cylindrical discs.
[0078] FIG. 22A is a computer generated model of a linear expander
formed by an additive manufacturing process that can expand upon,
or following, exposure to an external stimulus.
[0079] FIG. 22B is a computer generated model of a linear expander
formed by an additive manufacturing process that has expanded upon
exposure to an external stimulus.
[0080] FIG. 22C is a series of photographs showing the
transformation of a linear expander upon exposure to an external
stimulus.
[0081] FIGS. 23A-C are photographs showing curling.
DETAILED DESCRIPTION OF THE INVENTION
[0082] A description of example embodiments of the invention
follows.
[0083] As used herein, the term "object" and "objects" refers to
physical objects produced by an additive manufacturing process.
[0084] As used herein, the term "a," as used in describing "a first
additive manufacturing material," "a second additive manufacturing
material," and "a third additive manufacturing material," means "at
least one." It should be understood that first, second, and third
additive manufacturing materials are often described herein for
ease of convenience; however, any number of additive manufacturing
materials can be used to create a range of transformations over
time in various combinations at joints or other locations of
objects or objects in their entireties.
[0085] As used herein, the term "manufactured shape" refers to a
predetermined geometrical shape. For example, a manufactured shape
is different from a shape that would occur if an additive
manufacturing material were simply melted post-manufacturing in an
uncontrolled manner. Thus, a manufactured shape can be the shape of
an object as it is produced by an additive manufacturing apparatus,
such as a 3D printer. A manufactured shape can also be a shape
having a distinct structure and/or function. In other words, a
shape that is not a predetermined shape is not a manufactured
shape. An object according to embodiments disclosed herein can have
a first manufactured shape and at least one second manufactured
shape, wherein a predicted transformation occurs to change a state
of a manufactured object from the first manufactured shape to the
at least one second manufactured shape. It should be understood
that the term "predetermined" does not mean that every parameter,
such as volume, angle, stiffness, etc., is known in advance, but
rather that a shape is considered to be a manufactured shape
generally predicted at the time of manufacturing the object.
Depending upon the type of transformation, the actual shape may
differ from the predetermined shape by .+-.5%, .+-.10%, .+-.30%, or
.+-.50%.
[0086] As used herein, the term "non-biasing," as used with respect
to an external stimulus, means that the external stimulus does not
apply a mechanical or other force on the object in order to
transform the object from one manufactured shape to another
manufactured shape that is different from the transformation(s)
encoded in the object, as described herein. For example, exposing
an object to an external stimulus, such as exposure to a solvent,
temperature change, electromagnetic energy (e.g., light), or
pressure change is a non-biasing external stimulus because it does
not apply a mechanical force more in any particular spatial
direction.
4D Printing
[0087] Four dimensional (4D) printing is a novel process that
entails the multi-material printing of objects having the
capability to transform over time. As described herein, three of
the dimensions are spatial, and the fourth dimension refers to the
transformation of an object over time. For example, printed
structures can transform from a first shape into at least one
second shape due to exposure to at least one external stimulus.
[0088] Multi-material three-dimensional (3D) printing technologies
can allow for fabrication of 3D objects having a heterogeneous
composition. For example, 3D printed objects can be composed of two
or more materials that differ in one or more of their physical and
chemical properties. The Objet.RTM. line of 3D printers (Stratasys
Ltd., Israel) can be used for the 3D printing of multi-material
objects. Such printers are described in U.S. Pat. Nos. 6,569,373;
7,225,045; 7,300,619; and 7,500,846; and U.S. Patent Application
Publication Nos. 2013/0073068 and 2013/0040091, each of the
teachings of which being incorporated herein by reference in their
entireties. The Stratasys.RTM. Connex.TM. multi-material printers
provide multi-material Polyjet.TM. printing of materials having a
variety of properties, including rigid and soft plastics and
transparent materials, and provide high-resolution control over
material deposition.
[0089] Printing materials having differing physical or chemical
properties provides a user with the capability of programming
object structure and composition in order to achieve specific
functionality. For example, different combinations of a first, or a
first and second (or more), additive manufacturing materials can
form complex objects that cannot be generated otherwise in a single
process. Among other uses, single or multi-material 3D printing can
be used to generate heterogeneous objects having areas of different
stiffness. When the shape of these areas have a preferred
orientation, an object having anisotropic properties can be formed.
One example is an object having different properties (e.g., elastic
modulus) in different directions (e.g., X/Y/Z). Property gradients
can also be formed by gradually modifying the ratio of components
having different properties. For example, the ratio of low and high
swell components can be modified over a specific line or plane in
the 3D object. Layered structures can be made, where a rigid
component is wrapped or placed over a soft component.
Alternatively, a soft component can be wrapped or layered over a
rigid component, or the structure can include more than two layers.
This is used, for example, for functional living hinge
construction. An object can be printed in a first shape that, upon
exposure to an external stimulus, transforms into a second,
predetermined shape. For example, a gradient of the first and
second additive manufacturing materials can be varied to cause more
or less curvature during the transformation.
[0090] Current 3D printers can also utilize support materials. For
example, a support material can support a 3D printed object during
the printing process, which may be desirable or necessary if the
object has a shape that cannot support itself (e.g., the shape has
overhangs that, without support material or support material
constructions, would not be printable). The support material can be
positioned prior to beginning the 3D printing process, or it can be
printed by the 3D printer substantially simultaneously with the
printing of the additive manufacturing material. In some cases, the
support material can be removable after the printing process is
complete (e.g., by mechanical force, such as by use of a water jet
apparatus). Typically, the support material is removed before
transforming the object from a first shape into a second shape.
[0091] One of skill in the art will understand that in all of the
specific examples described herein, it may be necessary to cure
(e.g., polymerize) the object of additive manufacture (i.e., the
formulation or formulations that make up the cumulative layers of
the object). For example, it may be necessary to cure the object
prior to removal of support material, if any, and transformation of
the shape of the object.
[0092] It should be understood that while many of the embodiments
described herein include at least two additive manufacturing
materials, other embodiments can employ a single, given
manufacturing material. The additive manufacturing operations can,
for example, include applying more layers of the given additive
manufacturing material in certain locations and fewer, or none, in
others to encode a response to an external stimulus to cause a
predicted transformation to the shape of the object.
[0093] Using the ability to print several materials with different
properties simultaneously and control the placement of each
material in 3D, the listed abilities and examples are made
possible.
Joints
[0094] The object can have a first shape having joints. The joints
can be formed of different material types, such as a high swelling
material and a low swelling material. Upon exposure to an external
stimulus, the high swelling material can swell, causing a
transformation in the shape of the joint. For example, the joint
can curl, fold, stretch, shrink, and form a curved crease.
[0095] In one embodiment, a joint can curl. For example, a curling
joint can be formed by creating an object having a layer of a low
swelling material adjacent to a layer of a high swelling material.
Upon, or after, exposure to an external stimulus, the object will
curl away from the high swelling material (i.e., the low-swelling
material will be on the inside of the curl).
[0096] In one embodiment, a joint can fold. In one particular
embodiment, the joint can fold approximately 90.degree. in either
the clockwise or counterclockwise direction. In another embodiment,
a high swelling material expands so that two or more portions of
low swelling material contact each other. The portions of low
swelling material are shaped so that their forced interaction
restricts the degree of curvature.
[0097] In another embodiment, concentric rings of a high swelling
material can be alternated with concentric rings of a low swelling
material along a longitudinal axis. Upon, or after, exposure to an
external stimulus, the high swelling material expands, resulting in
linear elongation.
[0098] In another embodiment, a hole or lumen decreases in size
upon upon exposure to an external stimulus. A cylindrical object
can have an exterior portion formed of a low swelling material and
an interior portion formed of a high swelling material, wherein the
interior portion has a lumen. Upon, or after, exposure to an
external stimulus, the high swelling material in the interior of
the joint expands and decreases the diameter of the lumen.
[0099] In another embodiment, the joint can form a curved crease
upon exposure to an external stimulus. A curved crease can form
when low swelling portions of a structure constrain the deformation
of a joint in a way that creates deformation along other
directions. A first example can be formed from concentric,
alternating rings of high and low swelling material. A second
example can be formed by depositing a gradient of two additive
manufacturing materials. The center of the object can be a low
swelling material while the periphery is a high swelling
material.
[0100] In another embodiment, the joint can undergo linear
expansion. A linear expander can have a first end portion and a
second end portion that are formed, at least partially, of a low
swell material. The first and second end portions are connected via
two low swell portions that have curves that are mirror images of
each other. For example, the low swell portion on the left travels
upwards from the first end portion, curves counterclockwise for
approximately 90.degree., then curves clockwise for approximately
180.degree., then curves counterclockwise for approximately
90.degree.. The low swell portion on the left has three distinct
adjacent high swell portions. A first high swell portion is affixed
on the lower, exterior portion of the low swell material curve. A
second high swell portion is affixed on the middle, interior
portion of the low swell material. A third high swell portion is
affixed on the upper, exterior portion of the low swell material.
The low swell portion on the right travels along a trajectory that
is a mirror image of low swell portion on the left, and the high
swell portions on the right are similarly mirror images. Upon
exposure to an external stimulus, the three high swell portions
expand, causing the linear expander to expand. In other words, the
linear expansion joint has portions connected by an arrangement of
low and high swelling materials that form curling joints, the
synergistic effect of which is to provide linear expansion.
[0101] In general, the joints disclosed herein have a three
dimensional structure, which differs from joints that have only a
two dimensional structure. For example, some of the joints have
portions that mechanically interfere with each other to attune the
amount of folding.
Solvent-Based Transformation
[0102] In one embodiment, an additive manufacturing system can
deposit at least two different additive manufacturing materials.
After solidification (e.g., polymerization), the two additive
manufacturing materials can have differing degrees of swelling upon
exposure to an external stimulus. As illustrated in FIG. 1, a high
swelling material 10 can be printed adjacent to a low swelling
material 20. The high swelling material 10 has a first response to
an external stimulus, and the low swelling material 20 has a second
response to an external stimulus. In this example, the first
response is a greater degree of swelling upon exposure to the
external stimulus, and the second response is a lesser degree of
swelling upon exposure to the external stimulus. In many cases, the
low swelling material 20 has a minimal or undetectable response to
the external stimulus. In the arrangement of FIG. 1, exposure to an
external stimulus causes the high swelling material 10 to swell
more than the low swelling material 20. As a result, the object
transforms from a first shape into a second shape by curling. The
extent of distortion depends primarily on three factors. First, a
greater relative degree of swelling between the two materials leads
to a greater degree of deformation. Second, the relative stiffness
of the high and low swelling materials affects the extent of
distortion. A stiffer high swelling material and a softer low
swelling material will permit greater deformation. However, a very
soft low swelling material can be inefficient in creating
deformation and, alternatively, the overall structure may expand
but not change shape. In other words, if the low swelling material
is very soft, it will not exert enough force to resist the high
swelling material, so overall shape will not change. Third, a
thicker high swelling layer or a thinner low swelling material (or
both) will cause greater deformation.
[0103] A variety of combinations of high and low swelling materials
can be used. Typically, the high and low swelling materials will be
selected based on their response to a particular external stimulus.
One example of an external stimulus involves exposing the object to
a solvent. As one example, the solvent can be water, and the high
swelling material 10 is more hydrophilic than the low swelling
material 20. Stated differently, the low swelling material 20 is
more hydrophobic than the low swelling material 10. Alternatively,
the external stimulus can be exposure to a humid environment.
[0104] The high swelling material 10 can be a 3D printable material
that swells in an aqueous solvent. Particular types of materials
include UV-curable materials and other thermosetting materials.
After deposition of formulations and during the printing process,
the deposited material can be exposed to UV light or heat to cure
(e.g., polymerize) the material, resulting in a cured additive
manufacturing material having hydrophilic properties. One
particular example is a hydrophilic material that can be produced
by polymerizing a formulation formed of one or more hydrophilic
monomers and oligomers. Suitable examples are hydroxyethyl acrylate
and poly(ethylene) glycol. Other examples include formulations
composed of vinyl ethers, acrylamides, and/or epoxides.
[0105] A suitable UV-curable formulation resulting in a hydrophilic
material after polymerization can include approximately 50 to 90
percent of hydrophilic acrylic monomers and approximately 60 to 80
percent of oligomers. More preferably, a suitable formulation for a
hydrophilic material can include approximately 60 to 80 percent of
a hydrophilic acrylic monomer and approximately 10 to 20 percent of
oligomers.
[0106] A generalized formulation for a hydrophilic material is
disclosed in Table 1, which shows the approximate ranges of
components.
TABLE-US-00001 TABLE 1 Amount by weight (percent) Component 50-90%
Hydrophilic acrylic monomer 10-50% Hydrophobic oligomer 1-3%
Photoinitiator 0.1-0.2% Surface active agent 0.1-0.2% Stabilizer or
inhibitor
[0107] One particular example of a formulation for producing a
hydrophilic material is disclosed in Table 2. In the particular
formulation disclosed in Table 2, the hydrophilic monomer is
hydroxyethyl acrylate; the hydrophobic oligomer is composed of a
difunctional bisphenol A based epoxy acrylate; the photoinitiator
is an alphahydroxyketone; the surface active agent is a silicone
containing surface additive; and the inhibitor is a
hydroquinone.
TABLE-US-00002 TABLE 2 Amount by weight (grams) Component 70
Hydroxyethyl acrylate 15 Difunctional bisphenol A based epoxy
acrylate 2 Alphahydroxyketone 0.1 Silicone containing surface
additive 0.2 Hydroquinone
[0108] For the hydrophilic material described in Table 2, a
suitable external stimulus can be a polar solvent, such as water or
an alcohol.
[0109] The low swelling material 20 can be a 3D printable material
that does not swell, or that swells minimally, when exposed to an
aqueous solution. A formulation that includes one or more of
hydrophobic acrylic monomers and oligomers is an example of a
formulation that, after curing (e.g., polymerization), results in a
hydrophobic material. Suitable examples are disclosed in U.S. Pat.
No. 7,851,122, the entire teachings of which are incorporated
herein by reference. Particularly suitable examples include phenoxy
ethyl acrylate, trimethylol propane triacrylate, and isobornyl
acrylate.
[0110] Each of the hydrophilic and hydrophobic formulations can
include one or more of a photoinitiator, stabilizer, surfactant, or
colorant.
[0111] In one embodiment, it is possible to obtain a material
having controlled hydrophilicity by simultaneous deposition of low
and high hydrophilic formulations in predetermined ratios. For
example, this procedure can be used to produce a gradient of
hydrophilicity within the material.
Temperature-Based Transformation
[0112] In another embodiment, an additive manufacturing process can
be used to print an object having a first shape. This
temperature-based transformation can occur where the first and
second additive manufacturing materials have significantly
different coefficients of thermal expansion.
[0113] In one example, the object can soften when heated a first
time, and external force can be applied to transform the object
into a second shape. When cooled down, the object retains the
second shape. When heated a second time, the object reverts to the
first shape. Thus, the energy externally applied in the first
deformation is released upon exposure to an external stimulus, the
second heating.
[0114] In another example, a shape can be printed from two additive
manufacturing materials, a high swelling material and a low
swelling material. The shape can be immersed in hot water and
deformed. The low-swelling material softens due to the heat and
allows the swelling material to deform to the shape as it swells.
The shape is then cooled and dried at ambient temperature to yield
a cool, dry, deformed shape because as it cools, the low swelling
material becomes rigid again and prevents the shape from reverting
as the high swelling material dries and contracts. The shape is
then exposed to heat, which causes the shape to revert to the
originally printed shape.
[0115] Several different types of 3D printable materials are
suitable. Typically, the material is rigid below its glass
transition temperature (Tg) but soft and flexible above its Tg. One
particular material is the Objet VeroWhitePlus RGD835 (Stratasys
Ltd., Israel), which is rigid and stiff at room temperature but
very soft and flexible at 90.degree. C. As another example, the
Objet DurusWhite RGD30 material (Stratasys Ltd., Israel) is rigid
and stiff at room temperature but very soft and flexible at
75.degree. C. In one embodiment, the Tg can range from
approximately 75.degree. to approximately 90.degree. C. One of
skill in the art will recognize, however, that the Tg is not
restricted to the range of approximately 75.degree. C. to
approximately 90.degree. C. Rather, a wide variety of thermosetting
plastics are suitable, and the Tg can be any temperature that is
suitable for the particular application, e.g., approximately
0.degree. C. to approximately 150.degree. C.
[0116] More complex predicted transformations are also
contemplated. For example, an object can be printed from multiple
materials, each of which has a different Tg, thereby allowing
several shape transformations that occur at different
temperatures.
[0117] In addition, temperature-based materials can be combined
with swelling-based systems to create an object that transforms in
response to both exposure to solvent and temperature changes. For
example, a rigid hydrophobic material with a Tg of approximately
60.degree. C. can be combined with a hydrophilic material. When
placed in hot water, the first material softens and the hydrophilic
material swells, causing transformation. When removed to room
temperature, the first material becomes rigid again and retains its
shape, even when the swollen material dries. To reverse the first
transformation, the deformed structure can be heated, which causes
the rigid material to soften and the object to revert to its
original shape.
Pressure-Based Transformation
[0118] In another embodiment, an external stimulus can be a change
in pressure. For example, a cylindrical object having a
multimaterial composition can be printed by a 3D printer. The
exterior of the cylinder can be made of a first material that is
relatively rigid. The interior of the cylinder can be a second
material that is a soft, elastomer or other elastomer-like material
(e.g., polymerized Objet Tango Plus FLX930 material). The cylinder
can have a lumen through the middle. In response to a change in
pressure, the second material will change, thereby causing
deformation and changing the shape of the object.
Electromagnetic Energy-Based Transformation
[0119] In another embodiment, an external stimulus can be exposure
to electromagnetic energy. For example, an object can be formed of
two different materials having differential absorption
characteristics of electromagnetic energy. Upon, or following,
exposure to electromagnetic energy, a first material will heat up
more than a second material. The electromagnetic energy can be
within the infrared, visible, ultraviolet, or other portion of the
electromagnetic spectrum.
Apparatus and Non-Transient Computer Readable Medium for 4D
Printing
[0120] FIG. 14 is a block diagram of an apparatus for multimaterial
3D printing. Stored on the non-transient computer readable medium
510 is a sequence of instructions. When executed by a processor
520, the sequence of instructions causes a processor to access a
database 530 that includes first parameters of additive
manufacturing materials and second parameters for arranging the
additive manufacturing materials relative to each other to form at
least a portion of a shape of an object having a first shape in an
absence of an external stimulus and having a second, predicted
shape in a presence of, or following exposure to, the external
stimulus. The processor 520 can access the non-transient computer
readable medium 510 and the database 530 either via a local
connection or via a computer network. The processor can calculate,
as a function of the first and second parameters, a sequence of
machine-controllable instructions that, when provided to a 3D
printing apparatus 540, programs the 3D printing apparatus 540 to
produce the object in the first shape.
[0121] The database can further include parameters of an
environment in which the object will be employed. The sequence of
instructions can further cause the processor 520 to calculate
machine-controllable instructions as a function of the environment
or adjust the previously calculated machine-controllable
instructions as a function of the environment. The external
stimulus can be exposure to a solvent, temperature change,
electromagnetic energy, or pressure changes. The
machine-controllable instructions can cause the 3D printing
apparatus 540 to dispense a first additive manufacturing material
and a second additive manufacturing material in an arrangement
relative to each other to enable a predicted transformation of the
shape in response to the external stimulus. The external stimulus
can be a first external stimulus, and the predicted transformation
can be a first predicted transformation.
[0122] The machine-controllable instructions can further cause the
3D printing apparatus 540 to dispense a third additive
manufacturing material arranged relative to the first or second
additive manufacturing materials, or both. The third additive
manufacturing material can have a third response to the first
external stimulus or a second external stimulus to enable a
corresponding second predicted transformation of the shape of the
object in response to the first or second external stimulus.
EXEMPLIFICATION
Example 1
Formation of a Cube
[0123] In this example, a generally cylindrical object transforms
into a first generation of a fractal Hilbert curve in the shape of
a cube.
[0124] FIG. 2 is a schematic representation of an arrangement of a
low swelling material and a high swelling material that can form a
folding joint. The object has a generally cylindrical shape. Two
cylindrical discs 30 are spaced apart by a horizontal member 40.
The high swelling material 10 is placed on one side of the
horizontal member 40. The cylindrical discs 30 and horizontal
members 40 are made of a low swelling material. For example, the
high swelling material can be more hydrophilic than the low
swelling material. Stated differently, the low swelling material
can be more hydrophobic than the high swelling material. The
cylindrical discs 30 function as angle limiters. Upon exposure to
an external stimulus, the cylindrical discs 30 force the joint to
fold to an approximately 90.degree. angle. In order to change the
curvature of the joint, the spacing or diameter of the cylindrical
discs can be changed. Increasing the spacing between the
cylindrical discs creates a more acute angle. If the cylindrical
discs are spaced more closely together, very little folding will
occur because the discs will contact each other and prevent further
folding. The number of discs can also be modified as well.
[0125] FIGS. 3A and 3B are computer generated models of an object
formed by an additive manufacture process that can fold upon, or
following, exposure to an external stimulus. FIG. 3A is a
photograph of the object prior to exposure to an external stimulus,
and FIG. 3B is a photograph of the object after exposure to an
external stimulus. In this particular embodiment, the high swelling
material 10 is more hydrophilic than the low swelling material 20,
and the external stimulus is exposure to water. As shown in FIG.
3B, the high swelling material has expanded in size relative to the
low swelling material, causing a predicted bend in the joint.
[0126] FIGS. 4A-F are schematic representations of an arrangement
of folding joints that can form a cube. The cube is formed from a
series of joints similar to those shown in FIGS. 2, 3A, and 3B. The
edges of the cube are formed from low swelling cylindrical material
51-58. The joints 61-67 are orientated so that the generally
cylindrical shape transforms into a cube. For example, joint 62 is
rotated 90.degree. relative to joint 61 in order to align the
cylindrical materials 51-58 to form the edges of a cube.
[0127] FIG. 5 is a series of time-lapsed photographs showing a
transformation from a cylindrical object to a cube. The top image
shows the generally cylindrical first shape of the object. As
printed in a first shape, the object is approximately 18 inches
long. The middle image shows several superimposed photographs that
illustrate the predicted change of the object over time. The bottom
image is a photograph of the object after the transformation has
been completed. Geometrically, the cube is the first generation of
a fractal Hilbert curve, where a single line is drawn through all
eight points of the cube without overlapping or intersecting. In
this particular example, the low swelling material was Objet
VeroBlackPlus RGD875, and the high swelling material was a
formulation of the hydrophilic type described in Tables 1 or 2. The
object was immersed in hot water for approximately 15 to 30
minutes.
[0128] One of skill in the art will understand that the timeframe
of the transformation from a first shape to a second shape can
depend on a variety of factors. Increasing the solvent temperature
can decrease the amount of time required for the transformation.
For example, a similar transformation as in FIG. 5 using cold water
can require one hour or longer. In some cases, the transformation
upon exposure to water can be reversible or partially reversible.
Removing the object from the water after it has transformed to the
second shape can cause it to revert back to the first shape.
However, the object may not be completely straight, and for this
reason it may only partially reverse to the first shape.
Example 2
Transformation from a Cylinder to Letters
[0129] In this example, a generally cylindrical object transforms
into a series of letters that spell "MIT."
[0130] FIG. 6 is a table having four columns that: A) describe a
type of joint; B) provide a computer aided design (CAD) of the
joint; C) show an experimental representation of the joint after
exposure to an external stimulus; and D) illustrate a simulation
showing the predicted shape of the joint after exposure to an
external stimulus. Each of the joints in FIG. 6 can be used to
curve an object of additive manufacture upon exposure to an
external stimulus. Each of the joints has a different arrangement
of high swelling material 10 and low swelling material 20, and thus
each joint curves differently, as are illustrated in the
experimental and simulated curvature (columns C and D). The joint
designated Elbow-"bi" is particularly effective for creating larger
curvatures, though each of the joints listed, as well as
modifications and hybrids thereof, can provide suitable curvature.
In the VoxCAD simulation, the low swelling material was assigned a
modulus of 2 GPa and a thermal expansion of zero. The high swelling
material was assigned a modulus of 100 MPa and a thermal expansion
of 0.03.degree. C..sup.-1. Water expansion was simulated by
increasing the temperature to 50.degree. C. In general, all of the
joints illustrated in FIG. 6 are folding joints, though each folds
slightly differently.
[0131] FIGS. 7A and 7B are schematic representations of an
arrangement of a generally cylindrical object having a series of
joints that can transform into an object that spells the letters
"MIT." FIG. 7A is a top view, and FIG. 7B is a side view. The
letters are formed from low swelling material 221-239 with
intervening high swelling material 210. Upon exposure to an
external stimulus, the high swelling material 210 expands, and the
curved corners of the low swelling materials 221-239 are forced
together to form joints, thereby resulting in the schematic
representation shown in FIG. 7C, which spells the letters
"MIT."
[0132] FIG. 7D is a schematic illustrating an example joint having
low swelling materials 240 and 241 with intervening high swelling
material 210. Upon exposure to an external stimulus, the high
swelling material expands, and the two low swelling materials 240
and 241 are forced toward each other, resulting in the joint
illustrated in FIG. 7E. The relative curvature near the point of
contact between the two low swelling materials 240 and 241 causes a
predicted folding at the joint. By appropriately orientating the
low swelling materials 221-239, an object can be created that
predictably curves in 90.degree. angles in both the clockwise and
counterclockwise directions.
[0133] FIGS. 8A-D is a series of time-lapsed photographs showing a
transformation from a generally cylindrical object to an object
that spells the letters "MIT." The object corresponds to that
illustrated in FIGS. 7A-E. FIG. 8A shows the generally cylindrical
first shape of the object. As printed in a first shape, the object
is approximately one foot long. FIG. 8B shows several superimposed
photographs that illustrate the predicted change of the object over
time. FIG. 8C is a photograph of the object after the
transformation has been completed. FIG. 8D is a series of
non-superimposed photographs showing the predicted change of the
object over time. In this particular example, the low swelling
material was Objet VeroBlackPlus RGD875, and the high swelling
material was a formulation of the hydrophilic type described in
Tables 1 or 2. The object was immersed in hot water for
approximately 15 to 30 minutes.
Example 3
Formation of a Cube with Solid Sides
[0134] This example demonstrates surface transformations. A
two-dimensional flat plane was printed. The flat plane corresponds
to the six unfolded surfaces of a cube. At each of the joints, a
strip of high and low swelling material is arranged so that the
object transforms from a first shape to a second shape upon
exposure to an external stimulus. The arrangement of high and low
swelling material at each joint enables a 90.degree. curvature so
that the faces of the cube curve toward each other and stop curving
upon reaching the second, predetermined shape. When submerged in
water, the first shape transforms into a closed surface cube with
filleted edges.
[0135] FIGS. 9A-F are schematic representations of an object of
additive manufacture that can transform into a cube having solid
sides after exposure to an external stimulus. FIG. 9A is a top view
of the object, which is formed from six panels 320, one for each
face of the cube, with joints that fold upon exposure to an
external stimulus. In the embodiment shown in FIGS. 9A-F, each
joint has four rectangular members 330. While the embodiment shown
has four rectangular members, the joint can have greater or fewer
rectangular members. The panels 320 and rectangular members 330 are
formed from a low swelling material. Each of the joints is
characterized by high swelling material 310 that connects the
adjacent rectangular members 330. FIGS. 9B and 9D are schematic
illustrations of two panels 320 having a joint that can fold upon
exposure to an external stimulus. FIGS. 9C and 9E are schematic
illustrations of two panels 320 having a joint that has folded
after exposure to an external stimulus. FIG. 9F is a schematic
illustration of the object of additive manufacture illustrated in
FIG. 9A after exposure to an external stimulus.
[0136] FIG. 10A is a computer-generated model of an object formed
by an additive manufacturing process that can transform into a cube
upon exposure to an external stimulus. FIG. 10B is a
computer-generated model of the object of FIG. 10A that has
transformed into a cube after exposure to an external stimulus.
FIG. 11A is a photograph of the object of additive manufacture of
FIG. 10A. FIG. 11B shows several superimposed photographs that
illustrate the predicted change of the object over time. FIG. 11C
is a photograph of the object after the transformation has been
completed. FIG. 11D is a series of non-superimposed photographs
showing the predicted change of the object over time. In this
particular example, the low swelling material was Objet
VeroBlackPlus RGD875, and the high swelling material was a
formulation of the hydrophilic type described in Tables 1 or 2.
Example 4
Linear Elongation
[0137] In this example, the linear elongation of a hollow cylinder
is demonstrated.
[0138] FIG. 12A is a schematic representation of an arrangement of
joints that can effect linear elongation. In the embodiment shown,
the object is shaped to form a hollow cylinder. The object has
alternating rings of high swelling material 410 and low swelling
material 420. Upon exposure to an external stimulus, the high
swelling material 410 expands, and the net effect is that the
hollow cylinder expands along its longitudinal axis. In this
particular example, the low swelling material was Objet
VeroBlackPlus RGD875, and the high swelling material was a
formulation of the hydrophilic type described in Tables 1 or 2.
[0139] FIG. 12B is a photograph of an object of additive
manufacture that is similar to the schematic representation of FIG.
12A. The photographs depict the linear elongation of the object of
additive manufacture upon exposure to an external stimulus.
Example 5
Curved Crease #1
[0140] In this example, a thin disc undergoes a curling
transformation.
[0141] FIGS. 13A-D depict an object of additive manufacture that
undergoes a curling transformation upon, or following, exposure to
an external stimulus. FIG. 13A is a schematic representation of an
object formed by an additive manufacturing process that can undergo
a curling transformation upon, or following, exposure to an
external stimulus. The center of the object is a low swelling
material (depicted in red) while the periphery is a high swelling
material (depicted in purple). The object is formed with a gradient
in the distribution of material from the center to the periphery.
Manufacturing an object with a gradient in the material
distribution is particularly difficult to achieve through
conventional, subtractive manufacturing processes.
[0142] FIGS. 13B and 13C are simulations showing the predicted
shape of the curling of FIG. 13A after exposure to an external
stimulus. The difference between FIGS. 13B and 13C is that FIG. 13B
is a simulation at a shorter duration of time after exposure to an
external stimulus than FIG. 13C.
[0143] FIG. 13D is a photograph of an object formed by an additive
manufacturing process that can undergo a curling transformation
upon, or following, exposure to an external stimulus. The image on
the left is the initial shape of the object as printed. The image
in the middle is the object after exposure to water for 30 minutes.
The image on the right is the object after exposure to water for 4
hours. In the later stages of deformation, the initial symmetry was
broken, and a wavy circumference shape was attained. This
transformation is generally referred to as a curved crease. In this
particular example, the low swelling material was Objet
VeroBlackPlus RGD875, and the high swelling material was a
formulation of the hydrophilic type described in Tables 1 or 2.
[0144] Thus, FIGS. 13A-D illustrate that complex distributions of
low and high swelling material can generate complex distortion
behavior.
Example 6
Hole Closure
[0145] This example describes a self-healing structure, wherein a
hole or lumen decreases in size upon exposure to an external
stimulus. As illustrated in FIG. 17, a cylindrical object can be
printed having a high swelling material 710 deposited in the
interior and a low swelling material 720 on the exterior. Upon
exposure to an external stimulus, the high swelling material 710 in
the interior of the cylinder expands to decrease the diameter of
the hole 730.
[0146] In a first iteration of this example, the low swelling
material 720 can be relatively rigid, and the high swelling
material 710 can be a soft elastomer or elastomer-like material
(e.g., polymerized Objet Tango Plus FLX930 material). The external
stimulus can be a change in pressure, which causes the high
swelling material 710 to expand and decrease the volume of the
lumen.
[0147] In a second iteration of this example, the low swelling
material 720 can be Objet VeroBlackPlus RGD875, and the high
swelling material can be a formulation of the hydrophilic type
described in Tables 1 or 2. The external stimulus can be exposure
to water, which causes the high swelling material 710 to expand and
decrease the volume of the lumen.
[0148] In a third iteration of this example, the low swelling
material 720 can be relatively rigid that does not change shape
appreciably upon exposure to electromagnetic energy (e.g., light),
and the temperature of the high swelling material 710 can increase
upon exposure to electromagnetic energy (e.g., light). The high
swelling material 710 can then expand similarly to the
temperature-response embodiment described below in reference to
Example 8. For example the low swelling material 720 can be a clear
plastic that allows light to penetrate.
Example 7
Three Material Systems
[0149] In another embodiment, first and second additive
manufacturing materials are low swelling materials having different
rigidity that are arranged relative to a third, high swelling
additive manufacturing material. The amount of deformation can be
adjusted by altering the relative amounts of the first and second
low swelling materials. As illustrated in FIGS. 15A and 15B, a high
swelling material 610 can be printed adjacent to a first low
swelling material 620, which, in turn, is printed adjacent to a
second low swelling material 630. The relative thickness of the
first and second low swelling materials 620 and 630 can be adjusted
to control the amount of deformation. In one particular embodiment,
the first low swelling material 620 can have a lower rigidity than
the second low swelling material 630. Using a thicker layer of the
second low swelling material 630 that has a higher rigidity or a
thinner layer of the first low swelling material that has a lower
rigidity, or both as illustrated, can decrease the amount of
deformation. Increasing the thickness of the high swelling material
610 can also have the same effect. The technique is not limited to
only three materials, but rather any particular number of low
and/or high swelling materials can be printed, such as three, four,
five, or more. In another particular embodiment, the first low
swelling material 620 can have a higher rigidity than the second
low swelling material 630. In other embodiments, the relative
positions of the high swelling material 610, the first low swelling
material 620, and the second low swelling material 630 can be
adjusted. For example, the first low swelling material 620 can be
on top, the high swelling material 610 can be in the middle, and
the second low swelling material 620 can be on the bottom.
Example 8
Temperature-Based Transformation
[0150] FIGS. 16A-C illustrate an object of additive manufacture for
use in a temperature-based transformation. An object having a shape
can be printed from two additive manufacturing materials, a high
swelling material 660 and a low swelling material 670, as
illustrated in FIG. 16A. The shape can be immersed in hot water and
deformed to yield the object of FIG. 16B, which is then cooled and
dried at ambient temperature to yield a cool, dry, deformed shape.
The shape is then exposed to heat, which causes the shape to revert
to the originally printed shape, as illustrated in FIG. 16C.
[0151] Several different types of 3D printable materials are
suitable. Typically, the material is rigid below its glass
transition temperature (Tg) but soft and flexible above its Tg. One
particular material is the Objet VeroWhitePlus RGD835 (Stratasys
Ltd., Israel), which is rigid and stiff at room temperature but
very soft and flexible at 90.degree. C. As another example, the
Objet DurusWhite RGD30 material (Stratasys Ltd., Israel) is rigid
and stiff at room temperature but very soft and flexible at
75.degree. C. In one embodiment, the Tg can range from
approximately 75.degree. to approximately 90.degree. C. One of
skill in the art will recognize, however, that the Tg is not
restricted to the range of approximately 75.degree. C. to
approximately 90.degree. C. Rather, a wide variety of thermosetting
plastics are suitable, and the Tg can be any temperature that is
suitable for the particular application, e.g., approximately
0.degree. C. to approximately 150.degree. C.
Example 9
Curved Crease #2
[0152] This example describes a curved crease formation.
[0153] An object of additive manufacture can be printed in a first
shape. The first shape is generally annular. The first shape is
printed with concentric, alternating rings of high swelling and low
swelling material.
[0154] The top two photographs of FIG. 18A illustrate the generally
annular shape and concentric, alternating rings of high and low
swelling material. The bottom two photographs of FIG. 18A
illustrate the object after exposure to an external stimulus. As
can be seen, the object develops a wavy curve that is generally
referred to as a curved crease. FIG. 18B is additional photographs
of the same object of FIG. 18A.
Example 10
Octahedron
[0155] This example describes the formation of an octahedron.
[0156] FIG. 19 is a series of photographs of an object of additive
manufacture that can fold to form an octahedron. The photograph on
the left illustrates the object as printed. The photograph in the
middle is a series of superimposed time-lapsed photographs showing
the transformation from the printed shape into an octahedron upon
exposure to an external stimulus. The photograph on the right is
the object after exposure to an external stimulus and shows the
complete transformation to an octahedron.
Example 11
Joint spacing
[0157] FIG. 20 is a series of photographs of joints having
differentially-spaced discs. The joints on the left side of the
photograph have cylindrical discs that are more closely spaced
together, while the joints on the right side of the photograph have
joints that are spaced farther apart. The joints having more
closely spaced cylindrical discs do not fold as much as the joints
having greater spacing between the cylindrical discs.
[0158] FIG. 21 is another series of photographs of joints having
differentially-spaced discs. The joints on the left side of the
photograph have cylindrical discs that are more closely spaced
together, while the joints on the right side of the photograph have
joints that are spaced farther apart. The joints having more
closely spaced cylindrical discs do not fold as much as the joints
having greater spacing between the cylindrical discs.
[0159] While the spacing is illustrated with respect to joints
having a cylindrical disc, one of skill in the art will understand
that the principle is similarly applicable to joints having
rectangular members, such as those described in FIGS. 9A-F, 10A-B,
and 11A-D.
Example 12
Linear Expander
[0160] This example describes the formation of a linear
expander.
[0161] FIG. 22A is a schematic representation of a linear expander
as formed by an additive manufacturing process. The linear expander
has a first end portion 730 and a second end portion 740 that are
formed, at least partially, of a low swell material. The first and
second end portions 730 and 740 are connected via two low swell
portions 720 that have curves that are mirror images of each other.
The low swell portion 720 on the left travels upwards from the
first end portion 730, curves counterclockwise for approximately
90.degree., then curves clockwise for approximately 180.degree.,
then curves counterclockwise for approximately 90.degree.. The low
swell portion 720 on the left has three distinct adjacent high
swell portions 711, 712, and 713. The high swell portion 711 is
affixed on the lower, exterior portion of the low swell material
curve. The high swell portion 712 is affixed on the middle,
interior portion of the low swell material 720. The high swell
portion 713 is affixed on the upper, exterior portion of the low
swell material 720. The low swell portion 720 on the right travels
along a trajectory that is a mirror image of low swell portion 720
on the left, and the high swell portions on the right are similarly
mirror images. Upon exposure to an external stimulus, the high
swell portions 711, 712, and 713 expand, causing the linear
expander of FIG. 22A to transform into the linear expander of FIG.
22B. In other words, the linear expansion joint has portions
connected by an arrangement of low and high swelling materials that
form curling joints, the synergistic effect of which is to provide
linear expansion.
[0162] FIG. 22C is a series of time-lapsed photographs showing the
transformation of a linear expander from a first shape to a second,
predetermined shape upon exposure to an external stimulus.
Example 13
Curling
[0163] This example describes the formation of a curling joint.
[0164] FIGS. 23A-C are photographs of an object of additive
manufacture that can curl upon, or following, exposure to an
external stimulus. In these particular examples, an object of
additive manufacture is formed having a low swelling layer adjacent
to a high swelling layer. Upon, or after, exposure to an external
stimulus, the object will curl away from the high swelling material
(i.e., the low-swelling material will be on the inside of the
curl).
[0165] The teachings of all patents, published applications and
references cited herein are incorporated by reference in their
entirety.
[0166] While this invention has been particularly shown and
described with references to example embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
scope of the invention encompassed by the appended claims.
* * * * *