Forming an interface layer for removable support

Patent metadata

Field	Value
Publication number	US-11969795-B2
Application number	US-201715469213-A
Country	US
Kind code	B2
Filing date	Mar 24, 2017
Priority date	Apr 14, 2016
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

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

What is claimed is:

1. A method of fabricating a metallic three-dimensional object having a separable support, comprising the steps of:
forming a plurality of successive layers of build material into a desired shape of the three-dimensional object and a support structure, the build material including a binder system and a metal powder;
wherein during the step of forming a plurality of successive layers the desired shape of the three-dimensional object is connected to the support structure by a weak connection;
debinding at least a portion of the binder system; and
sintering the shape of the three-dimensional object in a sintering furnace into a densified final object and the support structure into a densified support structure separable therefrom at the weak connection; and
wherein the during the step of sintering the support structure is subject to drag on a furnace floor that, absent the presence of the support structure, the shape of the three-dimensional object would be subject to.

2. The method of claim 1 wherein the step of forming a plurality of successive layers of build material includes extruding the build material through a nozzle that is moved relative to a build plate.

3. The method of claim 2 wherein the step of extruding the build material through a nozzle includes delivering discrete units of the build material through an intermediary channel via a drive train.

4. The method of claim 1 wherein during the step of forming a plurality of successive layers the support structure is disposed on a surface of a build plate and extends upwards therefrom such that it is disposed below the desired shape of the three-dimensional object.

5. The method of claim 1 wherein the build material is adapted from a metal injection molding (“MIM”) feedstock.

6. The method of claim 1 wherein the densified final object includes at least two nested parts.

7. A method of fabricating a three-dimensional object having a separable support, comprising the steps of:
forming a plurality of successive layers of build material into a desired shape of the three-dimensional object and a support structure, the build material including a binder system and a sinterable powder;
wherein during the step of forming a plurality of successive layers the desired shape of the three-dimensional object is connected to the support structure by a weak connection;
debinding at least a portion of the binder system; and
sintering the shape of the three-dimensional object in a sintering furnace into a densified final object and the support structure into a densified support structure separable therefrom at the weak connection; and
wherein the during the step of sintering the support structure is subject to drag on a furnace floor that, absent the presence of the support structure, the shape of the three-dimensional object would be subject to during the step of sintering.

8. The method of claim 7 wherein the step of forming a plurality of successive layers of build material includes extruding the build material through a nozzle that is moved relative to a build plate.

9. The method of claim 8 wherein the step of extruding the build material through a nozzle includes delivering discrete units of the build material through an intermediary channel via a drive train.

10. The method of claim 7 wherein during the step of forming a plurality of successive layers the support structure is disposed on a surface of a build plate and extends upwards therefrom such that it is disposed below the desired shape of the three-dimensional object.

11. The method of claim 7 wherein the build material is adapted from a metal injection molding (“MIM”) feedstock.

12. The method of claim 7 wherein the densified final object includes at least two nested parts.

13. A method of fabricating a metallic three-dimensional object, comprising the steps of:
depositing a build material into a desired shape of the three-dimensional object and a support structure, the build material including a binder system and a sinterable powder;
wherein the support structure at least partially underlies the three-dimensional object and provides structural support to at least a portion of a feature thereof against gravity-induced deformation;
wherein during the step of depositing the build material into the desired shape of the three-dimensional object is connected to the support structure by a weak connection;
debinding at least a portion of the binder system;
sintering the shape of the three-dimensional object in a sintering furnace into a densified final object and the support structure into a densified support structure;
wherein the during the step of sintering the support structure is subject to drag on a furnace floor that, absent the presence of the support structure, the shape of the three-dimensional object would be subject to during the step of sintering; and
applying a mechanical force sufficient to separate the densified final object and the support structure at the weak connection without damage to the densified final object.

14. The method of claim 13 wherein the step of forming a plurality of successive layers of build material includes extruding the build material through a nozzle that is moved relative to a build plate.

15. The method of claim 13 wherein the step of extruding the build material through a nozzle includes delivering discrete units of the build material through an intermediary channel via a drive train.

16. The method of claim 13 wherein during the step of forming a plurality of successive layers the support structure is disposed on a surface of a build plate and extends upwards therefrom such that it is disposed below the desired shape of the three-dimensional object.

17. The method of claim 13 wherein the densified final object includes at least two nested parts.

18. A method comprising:
fabricating, from a first material, a support structure for an object;
fabricating a weak connection 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 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 weakly connects the support structure to the object during sintering;
and wherein the support structure is subject to drag on a furnace floor that, absent the presence of the support structure, the shape of the three-dimensional object would be subject to during the step of sintering.

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

• B22F3/1021 Primary

  Removal of binder or filler (removal of binder from ceramics C04B35/638) · CPC title

• B22F1/10

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

• B22F3/22

  for producing castings from a slip · CPC title

• B22F3/24

  After-treatment of workpieces or articles {(B22F3/1146 takes precedence)} · CPC title

• B22F7/02

  of composite layers {(B22F7/002 takes precedence)} · CPC title