Method for fabricating an interface layer to separate binder jetted objects from support structures

Patent metadata

Field	Value
Publication number	US-2017297100-A1
Application number	US-201715469425-A
Country	US
Kind code	A1
Filing date	Mar 24, 2017
Priority date	Apr 14, 2016
Publication date	Oct 19, 2017
Grant date	—

Abstract

Binder jetting techniques can be used to deposit and bind metallic particles or the like in a net shape for debinding and sintering into a final part. Where support structures are required to mitigate deformation of the object during the debinding and/or sintering, an interface layer may be formed between the support structures and portions of the object in order to avoid bonding of the support structure to the object during sintering.

First claim

1 . A method comprising:
depositing a number of layers of a powdered material in a bed, the powdered material including a sinterable powder of a material selected for sintering into a final part; applying a first binder in a first pattern to the number of layers as they are deposited to form a support structure from the powdered material within the bed; applying a second binder in a second pattern to the number of layers as they are deposited to form an object from the powdered material within the bed; and applying an interface material at an interface between the support structure and the object, wherein the interface material resists bonding of the support structure to the object during sintering.

2 . The method of claim 1 wherein the powdered material includes a metallic powder.

3 . The method of claim 1 wherein the first binder and the second binder are a substantially similar or identical binder system deposited from a single print head.

4 . The method of claim 1 wherein applying the interface material includes jetting the interface material through a jetting print head.

5 . The method of claim 1 wherein the interface material includes a colloidal suspension of ceramic particles sized to infiltrate the sinterable powder in a surface of the support structure adjacent to the object.

6 . The method of claim 5 wherein the ceramic particles have a mean particle size of less than one micron.

7 . The method of claim 5 wherein the sinterable powder has a mean particle size of about fifteen to thirty-five microns.

8 . The method of claim 5 wherein the ceramic particles have a mean particle size at least one order of magnitude smaller than a similarly measured mean particle size of the sinterable powder.

9 . The method of claim 1 wherein the interface material includes a layer of ceramic particles deposited at a surface of the support structure adjacent to the object.

10 . The method of claim 9 wherein the layer of ceramic particles is solidified to prevent displacement by subsequent layers of the sinterable powder, thereby forming a sinter-resistant ceramic layer between the support structure and the object.

11 . The method of claim 9 wherein the layer of ceramic particles is deposited in a carrier that gels upon contact with the sinterable powder.

12 . The method of claim 9 wherein the layer of ceramic particles is deposited in a curable carrier, the method further comprising curing the curable carrier substantially concurrently with deposition on the sinterable powder.

13 . The method of claim 1 wherein the interface material includes a material that remains as an interface layer physically separating the support structure from the object after debind and into a thermal sintering cycle.

14 . The method of claim 13 wherein the interface material is deposited in an intermittent pattern between the support structure and the object to create a corresponding pattern of gaps between the support structure and the object, thereby weakening a mechanical structure between the support structure and the object to facilitate removal.

15 . The method of claim 1 wherein the first binder is debindable with a chemical solvent, and wherein the interface material is at least partially non-soluble in the chemical solvent.

16 . The method of claim 1 wherein the interface material includes a soluble metal salt that transforms to a ceramic upon dehydration and heating.

17 . The method of claim 16 wherein the interface material includes at least one of a hydroxide, a chloride, a sulfate, a nitrate, an acetate, and a stearate.

18 . The method of claim 16 wherein the interface material further includes aluminum.

19 . The method of claim 16 wherein the interface material includes at least one of zirconium, yttrium, silicon, titanium, iron, magnesium, and calcium.

20 . The method of claim 1 further comprising applying successive layers of the powdered material in opposing directions with a bi-directional spreader.

21 . The method of claim 1 further comprising sintering the support structure and the object in a thermal sintering cycle.

22 . The method of claim 1 wherein the second binder includes a secondary infiltrant selected to modify properties of a final part formed by sintering the object.

23 . The method of claim 22 wherein the secondary infiltrant includes at least one of a carbon, a boron, and a metal salt.

Assignees

• Desktop Metal Inc

Inventors

• Gibson Michael Andrew
• Myerberg Jonah Samuel
• Sachs Emanuel Michael
• Fulop Ricardo
• Schuh Christopher Allan
• Chiang Yet-Ming
• Hart Anastasios John

Classifications

• B22F10/28

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title

• B22F10/32

  of the atmosphere, e.g. composition or pressure in a building chamber · CPC title

• B22F1/10

  Metallic powder containing lubricating or binding agents; Metallic powder containing organic material · CPC title

• B22F10/62

  by chemical means · CPC title

• B22F10/40

  Structures for supporting workpieces or articles during manufacture and removed afterwards · CPC title