Method for selective deposition modeling

• US 5,855,836 A
• Filed: 06/12/1997
• Issued: 01/05/1999
• Est. Priority Date: 09/27/1995
• Status: Expired due to Term

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Inventors: Hull, Charles W., Leyden, Richard N.
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US08/876,695
• Time in Patent Office: 572 Days
• Field of Search: 264/308, 264/401, 106/31.3, 106/31.62, 364/468.27, 524/62, 524/277, 524/296, 524/495, 524/563, 524/577
• US Class Current: 264/401
• CPC Class Codes: B29C 64/112 using individual droplets, e.g. from jetting heads
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing

Abstract

A novel thermopolymer material adapted for use in thermal stereolithography. More particularly, a thermopolymer material comprising a mixture of: a low shrinkage polymer resin; a low viscosity material such as paraffin wax; at least one microcrystalline wax; a toughening polymer, a plasticizer. Alternative embodiments further include components to improve the materials ability to transfer heat and to improve strength. The subject material, together with the described process greatly reduce part building distortions while retaining desirable toughness, strength and jetting properties.

Claims

1. A selective deposition modeling method of forming at least a portion of a three-dimensional object on a layer-by-layer basis, comprising the steps of:

a) generating computer data corresponding to layers of said object;

b) providing a building material which is a fluid at at least one temperature between 80°

C. and about 140°

C., comprising;

(i) about 20-80%_w of a reactive material;

(ii) about 10-30%_w of a low shrinkage polymer resin;

(iii) about 5-20%_w of at least one microcrystalline wax;

(iv) about 2-10%_w of a toughening polymer; and

(v) about 1-3%_w of a plasticizer;

c) elevating the temperature of said material to a temperature above 80°

C. to about 140°

C.;

d) selectively dispensing said material at said elevated temperature according to said computer data to form a layer of said object;

e) providing an environment that lowers the temperature of said dispensed material;

f) repeating steps d) and e) to form subsequent layers until at least said portion of the object is formed; and

g) reacting the reactive material included in at least one layer of the object.

2. The method of claim 1 wherein said reactive material is a photopolymer.

3. The method of claim 1 wherein the temperature of said material is elevated to a temperature about 90°

C.-130°

C.

4. The method of claim 1 wherein the temperature of said material is elevated until it has a viscosity in the range of about 18 cps to 25 cps.

5. The method of claim 1 wherein said material is configured to solidify over a range of at least 10°

C.

6. The method of claim 1 wherein said material comprises:

a) about 40-50%_w of a photopolymer;

b) about 20-30%_w of a hydrocarbon resin which is a copolymer of -methylstyrene and vinyl toluene;

c) about 15-20%_w of a combination of between 5 to 10%_w microcrystalline ester wax, between 5 to 10%_w soft microcrystalline wax, and between 2 to 5%_w hard microcrystalline wax;

d) about 5-10%_w of a low viscosity polymer with a melting point between 90°

C.;

e) about 1-5%_w of an ethylene-vinyl acetate copolymer with a viscosity of about 575 cps at about 140°

C. and a melting point of about 85°

C. to 95°

C.;

f) about 1-5%_w of tetrakis methane with a melting point about 110°

-125°

C.; and

g) about 1-5%_w of Diisononyl phthalate (DINP).

18. The method of claim 1 wherein the selective deposition modeling method is a thermal stereolithography method.

19. The method of claim 18 wherein the material is dispensed using an ink jet.

20. The method of claim 1 wherein said material is dispensed into an environment which is within about 10°

C. of a solidus temperature of the material.

28. The method of claim 20 comprising up to about 2.0%_w of the coloring agent.

31. The method of claim 1 wherein said building material is configured to have a viscosity of less than 25 cps at a temperature of about 90°

C.

7. A selective deposition modeling method of forming at least a portion of a three dimensional object on a layer-by-layer basis comprising the steps of:

a) generating computer data corresponding to the layers of said object;

b) providing a building material which is solid at ambient temperature and a fluid at at least one temperature between about 80°

C. and about 140°

C. comprising;

i) a low shrinkage thermoplastic resin,

ii) at least a first microcrystalline wax, said microcrystalline wax being present in an amount such that the building material solidifies over a broad temperature range, and

iii) a low viscosity polymer, said low viscosity polymer being present in an amount such that the viscosity of the building material when heated to a dispensable fluid state is suitable for delivery through a dispenser in a selective deposition modeling system;

c) elevating the temperature of said building material to a temperature in the range of about 80°

C. and about 140°

C. to cause said building material to become fluid;

d) selectively dispensing said building material in accordance with said computer data to form a cross-section of said three dimensional object when said material is elevated to a temperature in said range;

e) providing an environment that lowers the temperature of said dispensed building material; and

f) repeating steps d) and e) to form subsequent layers until at least said portion of the object is formed.

8. The method of claim 7 wherein the building material shrinks about 11% on cooling from about 130°

C. to about 25°

C.

9. The method of claim 8 wherein the building material transforms from a liquid to a solid over a temperature range of about 10°

C.

10. The method of claim 9 wherein the building material has a viscosity from about 18 to 25 cps at a temperature from about 125°

to about 130°

C.

21. The method of claim 7 wherein the selective deposition modeling method is a thermal stereolithography method.

22. The method of claim 21 wherein the material is dispensed from an ink jet device.

23. The method of claim 7 wherein the building material is dispensed into an environment which is within about 10°

C. of a solidus temperature of the material.

24. The method of claim 7 wherein the building material has a viscosity of about 7-28 cps at a temperature of about 125°

C. to about 135°

C.

25. The method of claim 8 wherein the building material transforms from a liquid to a solid over a temperature range of at least 10°

C.

26. The method of claim 7 additionally comprising a coloring agent.

29. The method of claim 7 additionally comprising the formation of a support structure from the building material, the support structure being removed after formation of the object.

11. A selective deposition modeling method of forming at least a portion of a three dimensional object on a layer-by-layer basis comprising the steps of:

a) generating computer data corresponding to the layers of said object;

b) providing a building material which is solid at ambient temperature and a fluid at at least one temperature between about 80°

C. and about 140°

C. comprising;

i) about 10-30%_w of at least one microcrystalline wax,

ii) about 20-60%_w of a low shrinkage material,

iii) about 10-40%_w of a low viscosity material, said low viscosity material not being included in i) or ii) above; and

iv) about 2-25%_w of a toughening polymer

c) elevating the temperature of said building material to a temperature in the range of about 80°

C. and about 140°

C.;

d) selectively dispensing a layer of said building material in accordance with said computer data to form a layer of said three dimensional object;

e) providing an environment that lowers the temperature of said dispensed building material; and

D repeating steps d) and e) to form subsequent layers until at least said portion of said three dimensional object is formed.

12. The method of claim 11 wherein the building material further comprises about 1-5%_w of a plasticizer.

13. The method of claim 11 wherein the selective deposition modeling method is a thermal stereolithography method.

14. The method of claim 13 wherein the material is dispensed from an ink jet device.

15. The method of claim 11 wherein said building material is configured to have a viscosity between about 7 to 28 cps at at least one temperature between about 125°

C. and 135°

C.

17. The method of claim 11 wherein said material is dispensed into an environment which is within about 10°

C. of a solidus temperature of the material.

27. The method of claim 11 additionally comprising a coloring agent.

30. The method of claim 11 additionally comprising the formation of a support structure from the building material, the support structure being removed after formation of the object.

32. The method of claim 12 wherein said building material is configured to have a viscosity between about 18 and 25 cps at a temperature of about 130°

C.

33. The method of claim 12 wherein said building material is configured to have a viscosity of less than 25 cps at a temperature of about 130°

C.

34. The method of claim 32 wherein the temperature of said material is elevated to a temperature of about 125°

C. and 135°

C.

35. The method of claim 12 wherein the temperature of said material is elevated until it has a viscosity for dispensing in the range of about 18 cps to about 25 cps.

36. The method of claim 32 wherein said material is configured to solidify over a range of at least 10°

C.

37. The method of claim 32 wherein said material comprises;

a) about 20%_w of a paraffin wax;

b) about 50%_w of a hydrocarbon resin which is a copolymer of α

-methylstyrene and vinyl toluene;

c) a combination of between 10 to 15%_w medium hard microcrystalline ester wax, between 5 to 20%_w soft microcrystalline wax and between 5 to 10%_w hard microcrystalline wax;

d) about 1-5%_w of an ethylene-vinyl acetate copolymer with a viscosity of about 140°

C. and a melting point of about 85°

to 95°

C.;

e) about 1-5%_w of tetrakis methane with a melting point of about 110°

-125°

C.; and

f) about 1-5%_w of Diisonony phthalate (DINP).

16. The method of claimed 11 wherein the temperature of said material is elevated into said range of temperatures to a temperature such that it has a viscosity for dispensing of between about 7 cps to about 28 cps.