Supports for sintering additively manufactured parts

Patent metadata

Field	Value
Publication number	US-10377083-B2
Application number	US-201816057721-A
Country	US
Kind code	B2
Filing date	Aug 7, 2018
Priority date	Dec 2, 2016
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A method comprising forming a shrinking platform of layers of a composite, the composite including a metal particulate filler in a first matrix, forming a shrinking support of layers of the composite upon the shrinking platform, forming a first release layer of a release material upon the shrinking support, the release material including a ceramic particulate and a second matrix, and forming a part of the composite upon the shrinking support to form a portable assembly from the combined shrinking platform, shrinking support, release layer and part, wherein substantially horizontal portions of the part are vertically supported by the shrinking platform, wherein the first release layer is configured, after sintering, to separate the part from the shrinking support and to allow the part to be readily removed from the shrinking support, and wherein the shrinking support is configured to prevent the part from distorting during sintering.

First claim

What is claimed is:

1. A method of reducing distortion in an additively manufactured part, comprising:
forming a sintering tray through depositing successive layers of a composite, the composite including a metal particulate filler in a first matrix;
forming sintering supports through depositing successive layers of the composite upon the sintering tray, wherein the sintering supports are configured to support the part during a sintering process to prevent the part from distorting due to gravitational force;
forming the part through depositing successive layers of the composite above the sintering tray;
forming an interior structure in at least one of the sintering tray, the sintering supports, and the part, wherein the interior structure is comprised of a plurality of chambers having interconnections therebetween;
forming a first separation layer of a separation material upon the sintering supports, wherein the first separation layer is configured to separate the part from the sintering supports and to allow the part to be readily removed from the sintering supports after the sintering process, and wherein the separation material includes a particulate filler in a second matrix; and
forming from the sintering tray, the sintering supports, the first separation layer, and the part a portable assembly that is configured to be transported, debound, and sintered as a unit.

2. The method according to claim 1 , further comprising:
penetrating a fluid debinder into the interior structure to debind at least one of the first matrix and the second matrix from within the interior structure.

3. The method according to claim 1 , further comprising;
forming a lateral support shell of the composite following a lateral contour of the part; and
connecting the lateral support shell to the lateral contour of the part by forming separable attachment protrusions of the composite between the lateral support shell and the part.

4. The method according to claim 1 , further comprising:
providing a sliding particulate layer below the sintering tray, of equal or larger surface area than a bottom surface of the sintering tray, that reduces lateral resistance between the sintering tray and an underlying surface;
simultaneously debinding in a chamber the first matrix and the second matrix in the portable assembly to form a brown portable assembly during a debinding process; and
heating, during the sintering process, the brown portable assembly to shrink the sintering tray, the sintering supports, and the part at a uniform rate.

5. The method according to claim 4 , wherein the underlying surface comprises a portable build plate, wherein forming the sintering tray comprises forming the sintering tray above the portable build plate, wherein providing the sliding particulate layer comprises forming the sliding particulate layer below the sintering tray and upon the portable build plate with the separation material, and wherein the method further comprises:
keeping the portable assembly together as a unit during the debinding process;
sintering the brown portable assembly during the sintering process;
keeping the brown portable assembly together during the sintering process; and
separating, after the sintering process, the portable build plate, the sliding particulate layer, the sintering tray, the first separation layer, and the sintering supports from the part.

6. The method according to claim 4 , further comprising:
powderizing the first separation layer during the sintering process to leave loose particulate between the opposing surfaces.

7. The method according to claim 1 , further comprising:
forming a support structure of the composite in a location supported by the part; and
forming a second separation layer of the separation material intervening between the part and the support structure, wherein the support structure is configured to shrink while continuously being supported by the part during sintering of the portable assembly, and the second separation layer is configured to powderize during the sintering process to leave loose particulate that allows the support structure to be readily removed from the part after the sintering process.

8. The method according to claim 1 , further comprising:
forming a third separation layer of the separation material intervening between a surface of the part and a top surface of the sintering tray; and
forming a lowermost portion of the part from successive layers of the composite directly upon the third separation layer.

9. A method of reducing distortion in an additively manufactured part; comprising:
depositing successive layers of a composite to form a sintering tray, wherein the composite includes a metal particulate filler in a first matrix,
depositing successive layers of the composite upon the sintering tray to form a plurality of sintering supports, wherein the plurality of sintering supports are configured to support the part during a sintering process to prevent it from distorting due to gravitational force;
interconnecting the composite of the sintering tray to the composite of plurality of sintering supports to permit mass diffusion between metal particles found in the sintering tray that are adjacent to metal particles found in the plurality of sintering supports to unitarily shrink the sintering tray and plurality of sintering supports and to provide a continuous foundation for the plurality of sintering supports;
depositing a first separation layer of a separation material upon the plurality of sintering supports, wherein the separation material includes a particulate filler in a second matrix;
depositing successive layers of the composite above the sintering tray to form the part;
forming an interior structure in at least one of the sintering tray, sintering supports, and the part, wherein the interior structure is comprised of a plurality of chambers having interconnections therebetween;
forming a portable assembly from the sintering tray, the plurality of sintering supports, the first separation layer, and the part;
debinding, during a debinding process, the first matrix and second matrix within the portable assembly simultaneously in a chamber to form a brown portable assembly; and
heating, during the sintering process, the brown portable assembly to a temperature sufficient to simultaneously sinter and shrink the sintering tray, the plurality of sintering supports, and the part at a uniform rate.

10. The method according to claim 9 , further comprising:
penetrating a fluid debinder into the interior structure to debind the first matrix from within the interior structure.

11. The method according to claim 9 , further comprising:
forming a lateral support shell of the composite following a lateral contour of the part; and
connecting the lateral support shell to the lateral contour of the part by forming separable attachment protrusions of the composite between the lateral support shell and the part.

12. The method according to claim 9 , further comprising:
providing a sliding particulate layer below the sintering tray, of equal or larger surface area than a bottom surface of the sintering tray, that reduces lateral resistance between the sintering tray and an underlying surface;
transporting the portable assembly from an additive manufacturing printer to a first location for debinding; and
following the debinding process, transporting the brown portable assembly together from the first location to a second location for sintering; and
sintering, during the sintering process, the brown portable assembly at the second location.

13. The method according to claim 12 , wherein th

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B29C64/40 Primary

  Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof · CPC title

• B22F10/47

  characterised by structural features · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B22F3/1118

  comprising internal reinforcements · CPC title

• B29K2025/08

  Copolymers of styrene, e.g. AS or SAN, i.e. acrylonitrile styrene (B29K2055/02 takes precedence) · CPC title