Additive manufacturing with continuous debinding

Patent metadata

Field	Value
Publication number	US-2018154438-A1
Application number	US-201815862156-A
Country	US
Kind code	A1
Filing date	Jan 4, 2018
Priority date	Dec 2, 2016
Publication date	Jun 7, 2018
Grant date	—

Abstract

In printing a sinterable part using a 3D printing model material including a binder and a ceramic or metal sintering material, a release layer intervenes between support structures and the part, each of the support structures and the part formed of the model material. The release layer includes a spherized or powdered higher melting temperature material—ceramic or high temperature metal for example, optionally deposited with a similar (primary) matrix or binder component to the model material. After sintering, the release layer may become a loose powder, permitting the supports to be easily removed.

First claim

What is claimed is:

1 . A method of depositing part layers to form a part in additive manufacturing, comprising:
depositing a part layer of green material including a first binder and a sinterable powder; depositing a release layer of release material including a second binder and a release powder upon the part layer of green material; and debinding a portion of the first binder from the part layer of green material before depositing a subsequent layer of green material.

2 . The method according to claim 1 , further comprising:
depositing a plurality of part layers of green material; and debinding the plurality of part layers of green material before depositing a subsequent plurality of part layers of green material.

3 . The method according to claim 2 , further comprising:
depositing the part layer of green material with a print head; and debinding the portion of the first binder by immersing the part in solvent before depositing the subsequent plurality of part layers of green material.

4 . The method according to claim 1 , further comprising:
depositing the part layer of green material with a print head; and debinding the portion of the first binder with a debinding head following a same trajectory as the print head.

5 . The method according to claim 1 , further comprising:
debinding the portion of the first binder with a debinding head scanning across the part layer of green material.

6 . The method according to claim 1 , following debinding all part layers of green material of the part, sintering the entire part.

7 . A method of depositing material for additive manufacturing, comprising:
depositing a part layer of green material including a first binder and a sinterable powder; debinding a portion of the first binder from the part layer of green material to form a layer of brown material; depositing a release layer of release material including a second binder and a release powder upon the layer of brown material; and depositing a part layer of green material upon the part layer of brown material.

8 . The method according to claim 7 , further comprising:
following depositing a plurality of part layers of brown material, further debinding the brown material.

9 . The method according to claim 7 , further comprising:
following depositing a plurality of part layers of brown material, sintering the entire part.

10 . The method according to claim 9 , further comprising:
following depositing a plurality of part layers of brown material, pyrolysing the second binder during sintering to leave a loose layer of the release powder.

11 . An apparatus for additive manufacture of parts, comprising:
a sealed chamber in which a part is deposited; a heated build plate for receiving the deposited part; a print head that deposits part layers of model material containing a binder and a sinterable powder upon the heated build plate and upon prior deposited part layers; a debinding applicator that substantially continuously debinds the binder from the model material as it is deposited on the heated build plate; and a fume extractor that removes the debound binder from the sealed chamber.

12 . The apparatus according to claim 11 , wherein the fume extractor includes a vacuum pump that maintains the sealed chamber under vacuum.

13 . The apparatus according to claim 11 , wherein the debinding applicator includes a debinding head that substantially continuously follows a trajectory of the print head.

14 . The apparatus according to claim 13 , wherein a portion of the fume extractor is transported together with the debinding head to remove debound binder from a position continuously adjacent the debinding head.

15 . The apparatus according to claim 13 , wherein the debinding applicator operates upon one or more of the part layers, but fewer than all of the part layers, at one time.

16 . The apparatus according to claim 13 , wherein the debinding head includes a solvent nozzle that releases debinding fluid upon a part layer of green material.

17 . The apparatus according to claim 13 , wherein the debinding head includes a heat energy projector that projects heat energy upon a part layer of green material.

18 . The apparatus according to claim 11 , wherein the debinding applicator includes a debinding carriage that main scans a part a layer at a time to debind the debinder, and a portion of the fume extractor is transported together with the debinding carriage to remove debound binder from a position continuously adjacent the debinding carriage.

19 . The apparatus according to claim 11 , wherein the debinding applicator includes a solvent bath into which the part is immersed and removed before subsequent part layer deposition by the print head.

20 . The apparatus according to claim 11 , wherein the print head deposits part layers of model material upon prior deposited part layers that have not been debound by the debinding applicator as well as upon layers that have been debound by the debinding applicator.

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B22D11/01 Primary

  without moulds, e.g. on molten surfaces · CPC title

• B22F10/43

  characterised by material · 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

• B22F10/18

  by mixing binder with metal in filament form, e.g. fused filament fabrication [FFF] · CPC title

• B22F10/62

  by chemical means · CPC title