Forming an interface layer for removable support

Patent metadata

Field	Value
Publication number	US-2017297098-A1
Application number	US-201715469213-A
Country	US
Kind code	A1
Filing date	Mar 24, 2017
Priority date	Apr 14, 2016
Publication date	Oct 19, 2017
Grant date	—

Abstract

Support structures are used in certain additive fabrication processes to permit fabrication of a greater range of object geometries. For additive fabrication processes with materials that are subsequently sintered into a final part, an interface layer is formed between the object and support in order to inhibit bonding between adjacent surfaces of the support structure and the object during sintering.

First claim

1 . A method comprising:
fabricating, from a first material, a support structure for an object; forming an interface layer adjacent to the support structure; and fabricating a surface of the object from a second material, the surface of the object adjacent to the interface layer and the second material including a powdered material for forming a final part and a binder system including one or more binders, wherein the one or more binders resist deformation of a net shape of the object during processing of the object into the final part, wherein processing of the object into the final part includes debinding the net shape to remove at least a portion of the one or more binders and sintering the net shape to join and densify the powdered material, and wherein the interface layer resists bonding of the support structure to the object during sintering.

2 . The method of claim 1 wherein forming the interface layer includes fabricating the interface layer using at least one of fused filament fabrication, binder jetting, and stereolithography.

3 . The method of claim 1 wherein forming the interface layer includes inkjetting a ceramic-loaded slurry onto the support structure.

4 . The method of claim 1 wherein forming the interface layer includes depositing a suspension onto the support structure.

5 . The method of claim 4 wherein the suspension includes a medium resistant to sintering at a sintering temperature of the powdered material.

6 . The method of claim 4 wherein the suspension includes a selective embrittlement material that selectively embrittles a bond between the support structure and the surface of the object.

7 . The method of claim 6 wherein the suspension includes a composition selected to introduce crack defects into the interface layer.

8 . The method of claim 7 wherein the powdered material includes an alloy of at least one of aluminum, steel, and copper, and wherein the composition of the suspension includes at least one of antimony, arsenic, bismuth, lead, sulfur, phosphorous, tellurium, iodine, bromine, chlorine, and fluorine.

9 . The method of claim 1 wherein forming the interface layer includes at least one of inkjetting, spraying, micropipetting, and painting an interface material onto the support structure as the interface layer.

10 . The method of claim 9 wherein the interface layer includes a ceramic medium.

11 . The method of claim 1 wherein the interface layer includes a dissolvable material suitable for removal with a solvent prior to sintering.

12 . The method of claim 11 wherein the interface layer includes a ceramic powder that maintains a physical separation layer between the first material and the second material after the dissolvable material is removed.

13 . The method of claim 1 wherein the interface layer is formed of a material with a debind shrinkage rate or a sintering shrinkage rate substantially matching at least one of the first material of the support structure and the second material of the object under debind and sintering conditions suitable for at least one of the first material and the second material.

14 . The method of claim 1 wherein the first material of the support structure is configured to shrink at a greater rate than the second material of the object during at least one of debinding and sintering.

15 . The method of claim 14 wherein the greater rate is a rate selected to compensate for non-shrinkage in a ceramic material of the interface layer during at least one of debind and sintering.

16 . The method of claim 14 wherein the greater rate is selected so that the support structure pulls away from the object concurrently with the second material of the object sintering to a self-supporting density.

17 . The method of claim 1 wherein forming the interface layer includes oxidizing the interface layer to inhibit bonding to the second material of the object.

18 . The method of claim 17 wherein oxidizing the interface layer includes selectively oxidizing the interface layer with a laser.

19 . The method of claim 1 wherein the interface layer includes a material having a powdery macrostructure, the material retaining the powdery macrostructure while microscopically densifying to match a shrinkage rate of the object during sintering.

20 . The method of claim 19 wherein the material includes at least one of aluminum hydroxide and gamma alumina.

21 . The method of claim 1 wherein the interface layer includes at least one of an iron oxide and a ceramic-loaded polymer.

22 . The method of claim 1 wherein the interface layer includes a composition with a ceramic additive to inhibit bonding between the support structure and the surface of the object during sintering.

23 . The method of claim 1 further comprising depositing at least one of the support structure, the interface layer, and the object in a manner that inhibits bonding of the support structure to the object while sintering.

24 . The method of claim 1 further comprising depositing at least one of the support structure, the interface layer, and the object in a manner that inhibits mixing with the interface layer.

25 . The method of claim 1 wherein the powdered material includes a metal powder, and the interface layer is fabricated from a composition that includes a second phase material with a melting point below a sintering temperature of the metal powder to form a meltable interface that melts out of the interface layer as the metal powder achieves a sintering strength during sintering.

26 . The method of claim 1 wherein the interface layer is formed of a preceramic polymer decomposable into a ceramic during sintering.

27 . The method of claim 1 wherein the interface layer includes a ceramic non-reactive with the second material.

28 . The method of claim 1 wherein the second material includes titanium and the interface layer includes at least one of yttria and zirconia.

29 . The method of claim 1 wherein the first material and the second material have a similar or substantially identical composition.

30 . A method comprising:
receiving an article including a support structure fabricated from a first material, an interface layer adjacent to the support structure, and an object supported by the support structure and fabricated from a second material, the object having a surface adjacent to the interface layer, wherein the second material includes a powdered material for forming a final part and a binder system including one or more binders, wherein the one or more binders retain a net shape of the object during processing of the object into the final part, wherein processing of the object into the final part includes debinding the net shape to remove at least a portion of the one or more binders and sintering the net shape to join and densify the powdered material, and wherein the interface layer resists bonding of the support structure to the object during sintering; and processing the article into the final part, wherein processing the article includes at least one of debinding the article and sintering the article, and wherein processing the article further includes separating the object from the support structure at the interface layer.

Assignees

• Desktop Metal Inc

Inventors

• Myerberg Jonah Samuel
• Fulop Ricardo
• Gibson Michael Andrew
• Verminski Matthew David
• Fontana Richard Remo
• Schuh Christopher Allan
• Chiang Yet-Ming
• Hart Anastasios John

Classifications

• B22F10/62

  by chemical means · CPC title

• B22F10/18

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

• B22F1/10

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

• B22F10/64

  by thermal means (control of energy beam parameters for post heating B22F10/364) · CPC title

• B22F10/32

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