Supports for sintering additively manufactured parts

Patent metadata

Field	Value
Publication number	US-10040242-B2
Application number	US-201815892750-A
Country	US
Kind code	B2
Filing date	Feb 9, 2018
Priority date	Dec 2, 2016
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

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 shrinking supports of the composite upon the shrinking platform;
forming, in at least one shrinking support, a separation clearance dividing the 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 portable platform 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.

2. The method according to claim 1 , 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 platform assembly during deposition;
debinding the first matrix in the portable platform assembly from the green state to the brown state, in a first common chamber;
transporting the portable platform assembly in the brown state to a second common chamber for sintering;
sintering the portable platform 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 platform assembly during at least part of the sintering; and
maintaining, with the ceramic powder, the shrinking supports separate from the part.

3. The method according to claim 1 , wherein the separation clearance is formed as a vertical clearance separating neighboring shrinking supports and extending for substantially a height of the neighboring shrinking supports, and wherein the method further comprises:
separating the neighboring shrinking supports from one another along the vertical clearance.

4. The method according to claim 1 , wherein the first matrix and the second matrix are at least partially debindable by a common debinder.

5. The method according to claim 1 , wherein forming the separation clearance comprises forming the fragments as blocks separable from one another along the separation clearance contiguous within a plane intersecting the shrinking supports.

6. The method according to claim 1 , 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.

7. The method according to claim 6 , 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.

8. The method according to claim 6 , further comprising:
dividing the lateral support shell into shell fragments;
debinding the first matrix sufficient to form a portable assembly in the brown state including the shrinking platform, shrinking supports, lateral support shell, and part;
separating the lateral support shell into the shell fragments; and
separating the shell fragments from the part.

9. The method according to claim 1 , 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.

10. The method according to claim 1 , further comprising:
providing a sliding powder layer below the shrinking platform, of equal or larger surface area than a bottom of the shrinking platform, the sliding powder layer configured to reduce lateral resistance between the shrinking platform and an underlying surface during sintering.

11. 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 first shrinking support of the composite upon a first portion of the part and supporting 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;
forming, in the first shrinking support, a separation clearance dividing the first shrinking support into fragments separable along the separation clearance; and
forming the shrinking platform, first shrinking support, separation material, and part as a portable platform assembly in a green state, wherein the first binder component and third binder component are configured to maintain a shape of the portable platform assembly during depositing of the portable platform assembly, wherein the first shrinking support is configured to prevent the portable platform assembly from distorting from gravitational force during sintering of the metal particles of the portable platform 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.

12. The method according to claim 11 , 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 platform 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.

13. The method according to claim 11 , 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.

14. The method according to claim 11 , further comprising:
maintaining, with the first binder component and second binder component, a shape of the portable platform 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 platform assembly in the brown s

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

• B29C64/165

  using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber · CPC title

• B29C64/245

  Platforms or substrates (support structures intended to be sacrificed after manufacture B29C64/40) · CPC title

• B29K2079/085

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