Supports for sintering additively manufactured parts

Patent metadata

Field	Value
Publication number	US-10556384-B2
Application number	US-201816057730-A
Country	US
Kind code	B2
Filing date	Aug 7, 2018
Priority date	Dec 2, 2016
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

A method comprising depositing, in layers, a shrinking platform formed from a composite including metal particles embedded in a first matrix, depositing shrinking supports of the composite upon the shrinking platform, forming a separation clearance dividing at least one shrinking support into fragments, depositing, from the composite, a part upon the shrinking platform and shrinking supports, depositing a separation material intervening between the part and the shrinking supports, the separation material including a ceramic powder and a second matrix, and forming, from the shrinking platform, shrinking supports, separation material, and part, a portable platform assembly in a green state, wherein the shrinking support is configured to prevent the portable platform assembly from distorting from gravitational force during sintering of the metal particles of the assembly in a brown state, and wherein the ceramic powder of the separation material is configured to separate the shrinking support from the part following sintering.

First claim

What is claimed is:

1. A method of reducing distortion in an additively manufactured part, comprising:
depositing, in successive layers, a shrinking platform formed from a composite, the composite including metal particles embedded in a first matrix;
depositing, from the composite, a part upon the shrinking platform;
depositing a sliding layer below the shrinking platform, of equal or larger surface area than a bottom of the shrinking platform, the sliding layer configured to reduce lateral resistance between the shrinking platform and an underlying surface during sintering; and
forming, from the shrinking platform, sliding layer, and part, a portable assembly in a green state.

2. The method according to claim 1 , further comprising:
depositing shrinking supports of the composite upon the shrinking platform;
depositing a separation material intervening between the part and the shrinking supports, the separation material including a ceramic powder and a second matrix; and
forming the portable assembly from the shrinking platform, sliding layer, shrinking supports, separation material, and part in a green state, wherein the shrinking supports are configured to prevent the portable assembly from distorting due to gravitation force during sintering of the metal particles of the portable assembly in a brown state, and wherein the ceramic powder of the separation material is configured to separate the shrinking support from the part following sintering.

3. The method according to claim 2 , wherein the shrinking platform interconnects the shrinking supports with one another, and wherein the method further comprises:
maintaining, with the first matrix and second matrix, a shape of the portable assembly during deposition;
debinding the first matrix in the portable assembly from the green state to the brown state, in a first common chamber;
transporting the portable assembly in the brown state to a second common chamber for sintering;
sintering the portable assembly in the brown state to shrink at a rate uniform throughout as neighboring metal particles throughout the shape-retaining brown part assembly undergo atomic diffusion, and during sintering in the second common chamber, decomposing the second matrix to leave the ceramic powder loose via the heat of the sintering;
maintaining, with the first matrix, a shape of the portable assembly during at least part of the sintering; and
maintaining, with the ceramic powder, the shrinking supports separate from the part.

4. The method according to claim 3 , wherein the first matrix and the second matrix are at least partially debindable by a common debinder.

5. The method according to claim 2 , wherein depositing shrinking supports comprises forming a lateral support shell of the composite as the shrinking supports to follow a lateral contour of the part.

6. The method according to claim 5 , further comprising:
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.

7. The method according to claim 2 , further comprising:
depositing the separation material to intervene at a non-horizontal surface of the part opposing a surface of the shrinking supports, the non-horizontal surface of the part including at least one of a vertical surface, a curved surface, and a surface angled with respect to horizontal.

8. A method of reducing distortion in an additively manufactured part, comprising:
depositing, in successive layers, a shrinking platform formed from a composite, the composite including metal particles, a first binder component, and a second binder component;
depositing, from the composite, a part supported by the shrinking platform, the shrinking platform forming a foundation that holds the part and is configured, during shrinking of the composite, to prevent movement of the shrinking platform versus the part;
depositing a sliding layer below the shrinking platform, of equal or larger surface area than a bottom of the shrinking platform, the sliding layer configured to reduce lateral resistance between the shrinking platform and an underlying surface during sintering; and
forming the shrinking platform, sliding layer, and part as a portable assembly in a green state, wherein the first binder component is configured to maintain a shape of the portable assembly during depositing of the portable assembly.

9. The method according to claim 8 , further comprising:
depositing a first shrinking support of the composite upon a first portion of the part to support a second portion of the part;
depositing a separation material intervening between the part and the first shrinking support, the separation material including a ceramic powder and a third binder component, wherein the third binder component is responsive to a same debinder as the first binder component; and
forming the portable assembly from the shrinking platform, sliding layer, first shrinking support, separation material, and part in a green state, wherein the first binder component and third binder component are configured to maintain a shape of the portable assembly during depositing of the portable assembly, wherein the first shrinking support is configured to prevent the portable assembly from distorting due to gravitational force during sintering of the metal particles of the portable assembly in a brown state, and wherein the separation material is configured to separate the first shrinking support from the part during sintering and powderize to permit the first shrinking support to be removed from the part after sintering.

10. The method according to claim 9 , further comprising:
depositing second shrinking supports of the composite upon the shrinking platform, wherein the shrinking platform interconnects the shrinking supports with one another; and
depositing the separation material intervening between the part and the second shrinking supports, wherein the second shrinking supports are included in the portable assembly in the green state, and the ceramic powder of the separation material is configured to separate the second shrinking support from the part following sintering.

11. The method according to claim 9 , further comprising:
depositing the separation material intervening directly between the part and the shrinking platform, wherein the ceramic powder of the separation material is configured to separate the part from the shrinking platform following sintering.

12. The method according to claim 9 , further comprising:
maintaining, with the first binder component and second binder component, a shape of the portable assembly during deposition;
debinding the first binder component in the platform assembly from a green state to a brown state, in a first common chamber;
transporting the portable assembly in the brown state to a second common chamber;
sintering, in the second common chamber, the portable assembly in the brown state to shrink at a rate uniform throughout as neighboring metal particles throughout the shape-retaining brown part assembly undergo atomic diffusion and the second binder decomposes in the heat of sintering; and
decomposing the third binder component to leave the ceramic powder loose in the second common chamber.

13. The method according to claim 9 , wherein depositing the first shrinking support comprises forming a lateral support shell of the same composite as the first shrinking support to follow a lateral contour of the part.

14. The method according to claim 9 , wherein depositing the separation material comprises depositing the separation material to

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B29C70/16

  using fibres of substantial or continuous length {(non-woven fabrics per se D04H3/00)} · CPC title

• B29K2079/085

  Thermoplastic polyimides, e.g. polyesterimides, PEI, i.e. polyetherimides, or polyamideimides; Derivatives thereof · CPC title

• B29K2025/08

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

• B22F3/1118

  comprising internal reinforcements · CPC title

• B29C64/141

  using only solid materials · CPC title