Additive manufacturing of viscoelastic materials

Patent metadata

Field	Value
Publication number	US-11052597-B2
Application number	US-201715597068-A
Country	US
Kind code	B2
Filing date	May 16, 2017
Priority date	May 16, 2016
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

Described is a method of forming a structure having viscoelastic properties. The method can include a) depositing a layer of droplets of a solidifying material and a non-solidifying material, the droplets being deposited according to an occupancy matrix specifying voxels for the solidifying and non-solidifying materials, the solidifying and non-solidifying material being interspersed within the occupancy matrix, the occupancy matrix being generated by a probabilistic function; b) exposing the droplets of solidifying material to ultraviolet radiation to cure the solidifying material; and c) repeating a) and b) to deposit additional layers of droplets of solidifying and non-solidifying materials, thereby forming the structure having viscoelastic properties.

First claim

What is claimed is:

1. A method of forming a cellular foam having viscoelastic properties, the method comprising:
a) generating an occupancy matrix from a probabilistic function, wherein the probabilistic function is based on a prescribed percent liquid in a region of the cellular foam;
b) depositing a layer of droplets of a solidifying material and a non-solidifying material, the droplets being deposited according to the occupancy matrix specifying voxels for the solidifying and non-solidifying materials, the solidifying and non-solidifying material being interspersed within the voxels specified by the occupancy matrix;
c) exposing the droplets to ultraviolet radiation to cure the solidifying material, but not the non-solidifying material; and
d) repeating b) and c) to deposit additional layers of droplets of solidifying and non-solidifying materials, thereby forming the cellular foam having viscoelastic properties.

2. The method of claim 1 , wherein the probabilistic function is a random function.

3. The method of claim 1 , wherein the prescribed percent liquid is based on a predetermined physical property of the structure cellular foam.

4. The method of claim 3 , wherein the predetermined physical property of the cellular foam is storage modulus, loss modulus, or ratio of storage modulus to loss modulus.

5. The method of claim 3 , wherein the cellular foam has isotropic mechanical properties.

6. The method of claim 3 , wherein the cellular foam has anisotropic mechanical properties.

7. The method of claim 6 , wherein the percent liquid varies as a function of position.

8. The method of claim 6 , wherein the percent liquid is radially symmetric in two dimensions and varying in a third dimension.

9. The method of claim 8 , wherein the percent liquid varies with height.

10. The method of claim 1 , wherein each dimension of the voxels is between 5 μm and 50 μm.

11. The method of claim 1 , wherein 50% to 99% of the voxels are solidifying material.

12. The method of claim 11 , wherein 64% to 96% of the voxels are solidifying material.

13. The method of claim 1 , wherein the occupancy matrix has three dimensions.

14. The method of claim 1 , wherein the occupancy matrix has two dimensions.

15. The method of claim 1 , wherein the occupancy matrix specifies a region of the object.

16. The method of claim 1 , further comprising depositing a second solidifying material.

17. The method of claim 1 , further comprising depositing a second non-solidifying material.

18. The method of claim 1 , wherein the occupancy matrix for a subsequent layer is generated while depositing the layer of droplets of solidifying and non-solidifying materials.

19. The method of claim 1 , wherein the cellular foam is an open cellular foam.

20. The method of claim 1 , wherein the cellular foam is a closed cellular foam filled with liquid.

Assignees

• Massachusetts Inst Technology

Inventors

• Maccurdy Robert Bruce
• Rus Daniela
• Lipton Jeffrey Ian

Classifications

• B33Y10/00 Primary

  Processes of additive manufacturing · CPC title

• B29C64/112

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

• B33Y80/00

  Products made by additive manufacturing · CPC title

• B29C64/129 Primary

  characterised by the energy source therefor, e.g. by global irradiation combined with a mask · CPC title