# US 10,245,820 B2 · Forming sacrificial structures using phase-change materials that sublimate

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- Number: US 10,245,820 B2
- Document ID: US10245820B2
- Status: Granted
- Kind: B2
- Application number: 15/391,723
- Filed: 2016-12-27
- Published: 2017-04-20
- Granted: 2019-04-02
- Earliest claimed: 2014-12-11
- Assignees: Palo Alto Research Center Incorporated
- Applicants: Palo Alto Research Center Incorporated
- Inventors: Tse Nga Ng; Bing R. Hsieh; Steven E. Ready
- Web page: https://patentgrep.com/patent/US10245820B2

## CPC

- B29C 64/124: using layers of liquid which are selectively solidified
- B29C 33/448: {destructible (B29C33/52 takes precedence; in particular used in injection moulding B29C45/4457)}
- B29C 64/106: using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
- B29C 64/112: using individual droplets, e.g. from jetting heads
- B29C 64/118: using filamentary material being melted, e.g. fused deposition modelling [FDM]
- B29C 64/40: Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
- B33Y 10/00: Processes of additive manufacturing
- B29K 2075/00: Use of {PU, i.e.} polyureas or polyurethanes {or derivatives thereof}, as moulding material
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

A structure can include a first layer of a polymer material and a second layer of the polymer material on the first layer, the first and second layers of the polymer material defining a hollow space that was formed by way of a temporary sacrificial structure that was made of a sublimable material.

## Claims

### Claim 1

A method, comprising:
depositing a first layer of a polymer material;
depositing a first amount of sublimable material on the first layer of the polymer material to form a first sacrificial structure, wherein the sublimable material includes cyclododecane;
depositing a second layer of the polymer material on the first amount of sublimable material and first layer of the polymer material; and
removing the sublimable material to form a channel defined by the first and second layers of the polymer material.

### Claim 2 (depends on 1)

The method of claim 1, wherein the removing includes performing sublimation.

### Claim 3 (depends on 2)

The method of claim 2, wherein the sublimation includes heating at a certain temperature and at a certain pressure.

### Claim 4 (depends on 3)

The method of claim 3, wherein the certain pressure is approximately 1 millitorr.

### Claim 5 (depends on 3)

The method of claim 3, wherein the certain temperature is less than 160 degrees Celsius.

### Claim 6 (depends on 5)

The method of claim 5, wherein the certain temperature is approximately 55 degrees Celsius.

### Claim 7

A method, comprising:
depositing a first layer of a polymer material;
depositing a first amount of sublimable material on the first layer of the polymer material to form a first sacrificial structure;
depositing a second layer of the polymer material on the first amount of sublimable material and first layer of the polymer material;
removing the first amount of sublimable material to form a first hollow space defined by the first and second layers of the polymer material;
depositing a second amount of sublimable material on the first layer of the polymer material to form a second sacrificial structure;
depositing a third layer of the polymer material on the second amount of sublimable material and first layer of the polymer material; and
removing the sublimable material to form a second hollow space defined by the first and third layers of the polymer material.

### Claim 8

A method, comprising:
depositing a first layer of a polymer material;
depositing a first amount of sublimable material on the first layer of the polymer material to form a first sacrificial structure;
depositing a second layer of the polymer material on the first amount of sublimable material and first layer of the polymer material;
removing the first amount of sublimable material to form a first hollow space defined by the first and second layers of the polymer material;
depositing a second amount of sublimable material on the second layer of the polymer material to form a second sacrificial structure;
depositing a third layer of the polymer material on the second amount of sublimable material and second layer of the polymer material; and
removing the second amount of sublimable material to form a second hollow space defined by the second and third layers of the polymer material.

### Claim 9 (depends on 7)

The method of claim 7, wherein removing either or both of the first and second amounts of sublimable material includes performing sublimation.

### Claim 10 (depends on 9)

The method of claim 9, wherein the sublimation includes heating at a certain temperature and at a certain pressure.

### Claim 11 (depends on 10)

The method of claim 10, wherein the certain pressure is approximately 1 millitorr.

### Claim 12 (depends on 10)

The method of claim 10, wherein the certain temperature is less than 160 degrees Celsius.

### Claim 13 (depends on 7)

The method of claim 7, wherein either or both of the first and second amounts of sublimable material includes cyclododecane.

### Claim 14 (depends on 7)

The method of claim 7, wherein removing either or both of the first and second amounts of sublimable material includes performing sublimation.

### Claim 15 (depends on 14)

The method of claim 14, wherein the sublimation includes heating at a certain temperature and at a certain pressure.

### Claim 16 (depends on 15)

The method of claim 15, wherein the certain pressure is approximately 1 millitorr.

### Claim 17 (depends on 15)

The method of claim 15, wherein the certain temperature is less than 160 degrees Celsius.

### Claim 18 (depends on 8)

The method of claim 8, wherein either or both of the first and second amounts of sublimable material includes cyclododecane.