Additive fabrication support structures

Patent metadata

Field	Value
Publication number	US-9183325-B2
Application number	US-201414275459-A
Country	US
Kind code	B2
Filing date	May 12, 2014
Priority date	Apr 5, 2013
Publication date	Nov 10, 2015
Grant date	Nov 10, 2015

Abstract

Some aspects provide a method of generating a support structure for an object, the support structure and the object to be fabricated via one or more additive fabrication techniques, comprising identifying one or more regions of the object as one or more regions to which mechanical support is to be provided, identifying one or more support points within at least a first region of the one or more regions, and generating the support structure for the object, the support structure comprising one or more support tips coupled to the object at the one or more support points, the support tips being generated based at least in part on a direction normal to the surface of the object at the respective support point.

First claim

What is claimed is:

1. A method of generating a support structure for an object, the support structure and the object to be fabricated via one or more additive fabrication techniques, comprising:
identifying one or more regions of the object as one or more regions to which mechanical support is to be provided;
identifying one or more support points within at least a first region of the one or more regions;
determining, for each of the one or more support points, a direction normal to the surface of the object; and
generating the support structure for the object, the support structure comprising one or more support tips coupled to the object at the one or more support points,
wherein an orientation of each of the support tips is determined based at least in part on the determined direction normal to the surface of the object at a respective support point,
wherein the support structure comprises at least one scaffolding portion, and
wherein at least a first support tip of the one or more support tips contacts the at least one scaffolding portion at a non-zero angle.

2. The method of claim 1 , further comprising fabricating the support structure using the one or more additive fabrication techniques.

3. The method of claim 1 , wherein at least a subset of the one or more support tips are oriented in the direction normal to the surface of the object at the respective support point.

4. The method of claim 1 , wherein orientations of each of the one or more support tips are determined by applying an offset, based on directions of expected forces at the respective support point, to the direction normal to the surface of the object at the respective support point.

5. The method of claim 1 , wherein at least a first support tip of the one or more support tips has a strength determined based at least in part on a degree to which the first region is self-supporting.

6. The method of claim 1 , wherein the one or more support tips have geometries that depend, at least in part, upon a degree of support to avoid mechanical damage calculated based on directions of expected forces at respective support points.

7. The method of claim 6 , wherein the geometries include an asymmetric cross-sectional area of contact with the object.

8. The method of claim 7 , wherein at least a subset of the support tip geometries include a long axis and a short axis, and wherein the tips of the subset are positioned on the object such that the long axis of each tip is substantially perpendicular to a line extending from a centroid of the object.

9. The method of claim 7 , wherein at least a subset of the support tip geometries include a long axis and a short axis, and wherein the tips of the subset are positioned on the object such that the long axis of each tip is substantially normal to a direction of a force predicted to be exerted on the object during fabrication thereof.

10. The method of claim 1 , further comprising determining a plurality of layers that together correspond to a shape of the support structure.

11. The method of claim 1 , wherein the support structure is formed in contact with a build platform, and wherein the at least one scaffolding portion contacts the build platform.

12. The method of claim 1 , wherein the first support tip is mechanically weaker than the at least one scaffolding portion.

13. The method of claim 1 , wherein a length of the first support tip is less than 10% of a length of the at least one scaffolding portion.

14. The method of claim 1 , wherein the support structure comprises a plurality of scaffolding portions, and wherein each of the one or more support tips contacts a respective scaffolding portion of the plurality of scaffolding portions at a non-zero angle.

15. The method of claim 1 , wherein the at least one scaffolding portion is generated using a minimum spanning tree.

16. The method of claim 1 , wherein the support structure comprises a plurality of scaffolding portions, and wherein a majority of the one or more support tips contact a respective scaffolding portion at a non-zero angle.

17. The method of claim 16 , wherein the majority of the one or more support tips contact a respective scaffolding portion at angles greater than 15 degrees.

18. The method of claim 16 , wherein the majority of the one or more support tips contact a respective scaffolding portion at angles greater than 30 degrees.

19. The method of claim 1 , wherein the non-zero angle is greater than 30 degrees.

20. The method of claim 1 , wherein the non-zero angle is greater than 45 degrees.

21. The method of claim 1 , wherein the non-zero angle is greater than 60 degrees.

22. The method of claim 1 , wherein determining the direction normal to the surface of the object for at least a first support point of the one or more support points comprises:
constructing a voxel representation of the object, the representation comprising a plurality of voxels;
identifying a first voxel of the plurality of voxels as comprising the first support point; and
calculating the direction normal to the surface of the object for the first support point by determining whether one or more voxels neighboring the first voxel are exterior to the object.

23. The method of claim 1 , wherein determining the direction normal to the surface of the object for at least a first support point of the one or more support points comprises:
accessing data describing a plurality of polygons that describe the object, the data comprising a normal direction for each of the plurality of polygons;
identifying a first polygon of the plurality of polygons as comprising the first support point; and
identifying the normal direction associated with the first polygon as the direction normal to the surface of the object for the first support point.

Assignees

• Formlabs Inc

Inventors

• Wighton Shane
• Lobovsky Maxim
• Keeter Matthew
• Hogge Akimitsu

Classifications

• G06F2111/10

  Numerical modelling · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29C64/112

  using individual droplets, e.g. from jetting heads · CPC title

• B29C64/40 Primary

  Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof · 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