# US 11,993,006 B2 · Selective deposition-based additive manufacturing device and method of printing 3D parts with semi-crystalline materials

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- Number: US 11,993,006 B2
- Document ID: US11993006B2
- Status: Granted
- Kind: B2
- Application number: 17/615,366
- Filed: 2020-05-29
- Published: 2022-07-21
- Granted: 2024-05-28
- Earliest claimed: 2019-05-31
- Assignees: Evolve Additive Solutions, Inc.
- Applicants: Evolve Additive Solutions, Inc.
- Inventors: J. Samuel Batchelder; Eric Carl Stelter
- Web page: https://patentgrep.com/patent/US11993006B2

## CPC

- B29C 64/147: using sheet material, e.g. laminated object manufacturing [LOM] or laminating sheet material precut to local cross sections of the 3D object
- B29C 64/188: involving additional operations performed on the added layers, e.g. smoothing, grinding or thickness control (surface shaping B29C59/00; after-treatment of articles without altering their shape B29C71/00)
- B29C 64/218: Rollers
- B29C 64/223: Foils or films, e.g. for transferring layers of building material from one working station to another
- B29C 64/295: Heating elements
- B29C 64/321: Feeding
- B29C 64/227: Driving means
- 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
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 40/20: Post-treatment, e.g. curing, coating or polishing
- B33Y 70/00: Materials specially adapted for additive manufacturing
- 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

## Abstract

A selective deposition-based additive manufacturing system capable of building a three-dimensional (3D) part utilizing a semi-crystalline polymeric material includes at least one electrostatographic engine configured to develop one or more layers of particles of semi-crystalline polymeric material corresponding to one or more slices of a 3D model of a 3D part. The system includes a transfer medium configured to receive the one or more layers of particles of the semi-crystalline polymeric material on a front side from the at least one electrostatographic engine and to move the one or more layers away from the electrostatographic engine and a platen configured to carry the 3D part or support being printed. The system includes a gantry coupled to the platen and configured to move the platen into registration with the one or more layers, and a heater configured to heat a top surface of the 3D part being printed to a transfuse temperature. The system includes a layer transfer assembly having a roller contacting a back side of the transfer medium and a driver configured to cause the layer to transfer from the front side of the transfer medium to the heated top surface of the part. The system includes a cooler configured to cool the heated semi-crystalline polymeric material at a maximum rate of at least 20° C. per second such that the semi-crystalline material is in a super-cooled state wherein the semi-crystalline polymeric material does not completely initially crystallize.

## Claims

### Claim 1

A selective deposition-based additive manufacturing system capable of building a three-dimensional (3D) part utilizing a semi-crystalline polymeric material, the system comprising:
at least one electrostatographic engine configured to develop one or more layers including particles of semi-crystalline polymeric material corresponding to one or more slices of a 3D model of a 3D part or their corresponding supports;
a transfer medium configured to receive the one or more layers of particles of the semi-crystalline polymeric material on a front side from the at least one electrostatographic engine and to move the one or more layers away from the electrostatographic engine;
a platen configured to carry the 3D part or support being printed;
a gantry coupled to the platen and configured to move the platen into registration with the one or more layers;
a heater configured to heat a top surface of the 3D part being printed to a transfuse temperature;
a layer transfer assembly comprising:
a roller contacting a back side of the transfer medium; and
a driver configured to cause the layer to transfer from the front side of the transfer medium to the heated top surface of the part; and
a cooler configured to cool the heated semi-crystalline polymeric material at a rate of at least 20° C. per second such that the semi-crystalline material is in a super-cooled state wherein the semi-crystalline polymeric material does not completely initially crystallize.

### Claim 2 (depends on 1)

The system of claim 1, wherein the cooler is configured to cool the heated semi-crystalline polymeric material at a rate of at least 30° C. per second.

### Claim 3 (depends on 1)

The system of claim 1, wherein the cooler comprises an air tunnel that shears cooling air across the top surface of the 3D part as the material cools to the super-cooled state.

### Claim 4 (depends on 1)

The system of claim 1, wherein the cooler comprises an air tunnel or an air knife.

### Claim 5 (depends on 1)

The system of claim 1, wherein the transfer medium comprises a continuous belt.

### Claim 6

A method of printing a 3D part in a layer-wise manner with a semi-crystalline polymeric material utilizing a selective-deposition-based additive manufacturing system:
developing a first partial layer of semi-crystalline polymeric material using at least one electrostatotographic engine;
conveying the first partial layer from the at least one electrostatographic engine to a transfusion assembly with a transfer medium;
moving a platen carrying a 3D part being printed with a gantry to a location upstream from the transfusion assembly;
heating a top layer of the 3D part to a transfusion temperature;
registering the layer with the 3D part;
moving the 3D part and the layer through a transfusion assemble to thermally transfer the layer to the top surface of the 3D part while applying a pressure to a back surface of the transfer medium;
cooling the transfused layer to a temperature below a cold crystallization temperature at a rate of least 20° C. per second such that the semi-crystalline material is super-cooled; and
repeating the above steps until the 3D part is printed.

### Claim 7 (depends on 6)

The method of claim 6, wherein the cooling step comprises cooling the heated layer to super-cool the semi-crystalline material at a rate of least 30° C. per second.

### Claim 8 (depends on 6)

The method of claim 6, wherein the cooling step allows for less than 50% of full crystallization.

### Claim 9 (depends on 6)

The method of claim 6, wherein the cooling step allows for less than 30% of full crystallization.

### Claim 10 (depends on 6)

The method of claim 6, wherein the applying pressure step comprises applying between about 0.5 psi and about 200 psi to the back surface of the transfer medium.

### Claim 11 (depends on 6)

The method of claim 6, and further comprising:
subjecting the printed part to one or more post build processes to increase a volume percent crystallinity in the printed part.

### Claim 12 (depends on 6)

The method of claim 6, and further comprising:
developing a second partial layer of a second polymeric material using a second electrostatographic engine;
depositing the second partial layer onto the transfer medium with the first partial layer to form the first layer; and
conveying the first layer from the at least one electrostatographic engine to a transfusion assembly with a transfer medium.

### Claim 13 (depends on 12)

The method of claim 12, wherein the second polymeric material is semi-crystalline.

### Claim 14 (depends on 12)

The method of claim 12, wherein the second polymeric material is amorphous.

### Claim 15 (depends on 6)

The method of claim 6, wherein the cooling the part comprises varying cooling rate to adjust the initial crystallinity of the part being printed.

### Claim 16 (depends on 6)

The method of claim 6, wherein conveying the first partial layer comprises utilizing a continuous belt.