Systems and methods for designing and fabricating support structures for overhang geometries of parts in additive manufacturing

Patent metadata

Field	Value
Publication number	US-10010936-B2
Application number	US-201514940564-A
Country	US
Kind code	B2
Filing date	Nov 13, 2015
Priority date	Nov 13, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

Systems and methods are provided for designing and fabricating contact-free support structures for overhang geometries of parts fabricated using electron beam additive manufacturing. One or more layers of un-melted metallic powder are disposed in an elongate gap between an upper horizontal surface of the support structure and a lower surface of the overhang geometry. The powder conducts heat from the overhang geometry to the support structure. The support structure acts as a heat sink to enhance heat transfer and reduce the temperature and severe thermal gradients due to poor thermal conductivity of metallic powders underneath the overhang. Because the support structure is minimally or not connected to the part, the support structure can be removed with minimal or no post-processing step.

First claim

The invention claimed is:

1. An article of manufacture comprising:
a primary part comprising at least one overhang portion, the overhang portion having a lower surface;
a secondary part comprising a parallel support portion and at least one substantially vertical support portion extending between the parallel support portion and the lower surface of the overhang portion, the parallel support portion lying within a plane that is substantially parallel with the lower surface of the overhang portion,
wherein:
the lower surface of the overhang portion and the secondary part are fabricated during one process using the same metallic powder, and
an upper surface of the parallel support portion of the secondary part and the lower surface of the overhang portion of the primary part define an elongate gap therebetween, and un-melted metallic powder is disposed within the gap, and
the at least one vertical support portion has a first surface area in contact with the lower surface of the overhang portion, and the lower surface of the overhang portion has a second surface area that includes a total surface area of the lower surface, including the first surface area of the at least one vertical support portion, and a ratio of the first surface area to the second surface area is less than or equal to about 0.02.

2. The article in claim 1 , wherein the at least one vertical support portion comprises a first vertical support portion and a second vertical support portion, and the first surface area comprises the sum of the surface area of the first vertical support portion and the surface area of the second vertical support portion in contact with the lower surface of the overhang portion.

3. The article of claim 1 , wherein the at least one vertical support portion has a first outer perimeter length around an outer portion of the first surface area and the lower surface of the overhang portion has a second outer perimeter length, wherein a ratio of the first outer perimeter length to the second outer perimeter length is less than or equal to about 0.13.

4. The article of claim 1 , wherein the at least one vertical support portion is an upper vertical support portion and the secondary part further comprises at least one lower vertical support portion, the at least one lower vertical support portion extending between the parallel support portion and a build plate, the lower vertical support portion configured for conducting heat from the parallel support portion to the build plate.

5. The article of claim 4 , wherein the parallel support portion and the elongate gap are substantially parallel to the build plate.

6. The article of claim 4 , wherein the parallel support portion and the lower surface of the overhang portion extend at an angle greater than 0° relative to the build plate.

7. The article of claim 4 , wherein the lower vertical support portion comprises at least one leg extending between the parallel support portion and the build plate.

8. The article of claim 7 , wherein the parallel portion of the secondary part defines a perimeter, and the at least one leg comprises two or more legs that extend between the perimeter of the parallel portion to the build plate and are spaced apart from each other.

9. The article of claim 8 , wherein the parallel portion of the secondary part is rectangularly shaped, and each of the two or more legs are disposed at corners of the parallel portion.

10. The article of claim 4 , wherein the lower vertical support portion comprises one or more side walls that extend between a perimeter of the parallel support portion and the build plate.

11. The article of claim 10 , wherein the gap is a parallel gap, and a vertical gap is defined between the primary part and the side wall adjacent the primary part, wherein un-melted powder is disposed within the vertical gap.

12. The article of claim 4 , wherein the un-melted powder in the gap is configured for conducting heat from the overhang portion to the secondary part without fusing.

13. The article of claim 1 , wherein the one process comprises electron beam additive manufacturing.

14. The article of claim 1 , wherein the un-melted powder is disposed in a layer-by-layer fashion.

15. The article of claim 1 , wherein the overhang portion is a cantilever.

16. The article of claim 1 , wherein the overhang portion is an undercut portion.

Assignees

• Univ Alabama
• Nasa
• The Board Of Trustees Of The Univ Of Alabma
• Nasa

Inventors

• Chou Yuag-Shan
• Cooper Kenneth

Classifications

• G06F30/00 Primary

  Computer-aided design [CAD] · CPC title

• B33Y30/00

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B33Y50/00 Primary

  Data acquisition or data processing for additive manufacturing · CPC title

• G06F2119/18

  Manufacturability analysis or optimisation for manufacturability · CPC title