Systems and methods for electrophotography-based additive manufacturing of parts

Patent metadata

Field	Value
Publication number	US-2017192377-A1
Application number	US-201615386904-A
Country	US
Kind code	A1
Filing date	Dec 21, 2016
Priority date	Dec 31, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

In a method of producing a 3D part using an electrophotography-based additive manufacturing system, a plurality of layers of a powder-based material are developed using at least one electrophotography (EP) engine. The developed layers are transferred to a transfer medium. The layers on the transfer medium are dried by heating the layers without fully fusing the powder-based material to itself using a dryer. This reduces a water content of the layers. The dried layers are heated on the transfer medium to at least a fusion temperature, at which the power-based material fuses together, using a pre-transfusion heater. The dried layers are then transfused together on a build platform using a transfusion assembly to build the part in a layer-by-layer manner.

First claim

What is claimed is:

1 . A method of producing a 3D part using an electrophotography-based additive manufacturing system comprising:
developing a plurality of layers of a powder-based material using at least one electrophotography (EP) engine; transferring the developed layers to a transfer medium; drying the layers on the transfer medium comprising heating the layers without fully fusing the powder-based material to itself using a dryer, thereby reducing a water content of the layers; heating each of the dried layers on the transfer medium to at least a fusion temperature, at which the power-based material fuses together, using a first pre-transfusion heater; and transfusing the dried layers together on a build platform using a transfusion assembly to build the part in a layer-by-layer manner.

2 . The method according to claim 1 , wherein heating the layers comprises a heating step selected from the group consisting of radiating heat to the printed layers, blowing hot air over the printed layers, and emitting infrared radiation over the printed layers.

3 . The method according to claim 1 , wherein heating the layers without fully fusing the powder-based material to itself comprises heating the layers without fully Frenkel fusing the powder-based material to itself.

4 . The method according to claim 1 , wherein reducing a water content of the layers comprises reducing the water content of the layers to less than about 0.1% by weight using the dryer.

5 . The method according to claim 1 , wherein reducing a water content of the layers comprises reducing the water content of the layers to less than about 0.07% by weight using the dryer.

6 . The method according to claim 4 , wherein reducing a water content of the layers comprises reducing the water content of the layers from greater than about 0.4% water by weight to less than about 0.1% by weight using the dryer.

7 . The method according to claim 4 , wherein reducing the water content of the layers comprises heating the layers without bonding the printed layers to the transfer medium.

8 . The method according to claim 4 , wherein heating the layers comprises heating the layers on the transfer medium to a temperature in a range of about 150° C. to about 175° C. when the layers are formed of ABS.

9 . The method according to claim 4 , wherein transfusing the dried layers comprises processing each of the dried layers using a transfusion assembly including pressing each of the dried layers against a previously transfused dried layer supported on the build platform.

10 . The method according to claim 4 , further comprising heating a top surface of a layer supported on the build platform using a second pre-transfusion heater before transfusing the dried layers together.

11 . The method according to claim 1 , wherein developing a plurality of the layers comprises developing layers of the powder-based material using the at least one EP engine selected from the group consisting of part layers, and support structure layers.

12 . The method according to claim 11 , wherein transferring the developed layers to a transfer medium comprises electrostatically attracting the developed layers to the transfer medium.

13 . An electrophotography-based additive manufacturing system for producing 3D parts comprising:
a transfer assembly including a transfer medium, and a drive mechanism configured to feed the transfer medium in a feed direction; at least one electrophotography (EP) engine configured to develop layers of a powder-based material and transfer the layers to the transfer medium; a dryer positioned downstream of the at least one EP engine relative to the feed direction, and configured to heat the layers on the transfer medium to reduce a water content of the layers without fully fusing the powder-based part material; a first pre-transfusion heater positioned downstream of the dryer relative to the feed direction, the pre-transfusion heater configured to heat the layers on the transfer medium to at least a fusion temperature, at which the power-based material fuses together; and a transfusion assembly positioned downstream of the dryer and the first pre-transfusion assembly relative to the feed direction and configured to transfuse the layers to each other on a build platform in a layer-by-layer manner to build the part.

14 . The system according to claim 13 , wherein the dryer comprises a heating device selected from the group consisting of a resistive heating element, a radiant heater, an infrared radiation heater, and a hot air blower.

15 . The system according to claim 13 , wherein the dryer is configured to reduce the water content of the layers on the transfer medium to less than about 0.1% by weight.

16 . The system according to claim 15 , wherein the dryer is configured to reduce the water content of the layers on the transfer medium to less than about 0.07% by weight.

17 . The system according to claim 15 , wherein the dryer is configured to reduce the water content of the layers on the transfer medium without bonding the layers to the transfer medium.

18 . The system according to claim 15 , wherein the dryer is configured to heat the layers on the transfer medium to a temperature that is in the range of about 150° C. to about 175° C. when the layers are formed of ABS.

19 . The system according to claim 15 , wherein the layers comprise part layers and support structure layers.

20 . The system according to claim 15 , further comprising a second pre-transfusion heater configured to heat at least a top surface of the layers on the build platform.

Assignees

• Stratasys Inc

Inventors

• Batchelder J Samuel
• Chowdry Arun
• Chillscyzn Steven A

Classifications

• B33Y10/00

  Processes of additive manufacturing · CPC title

• G03G15/224

  Machines for forming tactile or three dimensional images by electrographic means, e.g. braille, 3d printing · CPC title

• G03G2215/1695

  at the second or higher order transfer point · CPC title

• G03G15/1625

  on a base other than paper · CPC title

• B33Y30/00 Primary

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title