Flash curing in selective deposition modeling

• US 20030209836A1
• Filed: 05/07/2002
• Published: 11/13/2003
• Est. Priority Date: 05/07/2002
• Status: Active Grant

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Inventors: Sherwood, Michael Thomas
• Granted Patent: US 7,270,528 B2
• Time in Patent Office: Days
• US Class Current: 264/401
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 35/0805 using electromagnetic radiation
• CPC Class Codes: B29C 64/112 using individual droplets, e.g. from jetting heads
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images

Abstract

A flash curing system for solid freeform fabrication which generates a plurality of radiation emitting pulses that forms a planar flash. The planar flash initiates curing of a curable material dispensed by a solid freeform fabrication apparatus. The radiation emitting pulses have a high peak power value that releases a sufficient quantity of free radicals from the photoinitiator to initiate curing and overcome the problem of oxygen inhibition. Substantially less power is consumed and less heat generated by the flash curing system compared to conventional continuous emission curing systems.

Claims

1. A method of forming a three-dimensional object in a layerwise manner in a build environment, the method comprising the steps of:

generating computer data corresponding to layers of the object;

dispensing a curable material in the build environment according to the computer data to form layers of the object;

supporting the dispensed material in the build environment; and

exposing the dispensed material to at least one planar flash of radiation to cure the dispensed material, the planar flash comprising a plurality of radiation emitting pulses that initiate curing of the dispensed material.

2. The method of claim 1 wherein between about 1 joule to about 15 joules of input energy are needed for generating each radiation emitting pulse.

3. The method of claim 1 wherein between about 1 to about 5 joules of input energy are needed for generating each radiation emitting pulse.

4. The method of claim 1 wherein about 3.5 to about 4.5 joules of input energy are needed for generating each radiation emitting pulse.

5. The method of claim 1 wherein less than about 1000 watts of power is consumed when exposing the dispensed material to the at least one planar flash.

6. The method of claim 1 wherein less than about 800 watts of power is consumed when exposing the dispensed material to the at least one planar flash.

7. The method of claim 1 wherein less than about 600 watts of power is consumed when exposing the dispensed material to the at least one planar flash.

8. The method of claim 1 wherein less than about 500 watts of power is consumed when exposing the dispensed material to the at least one planar flash.

9. The method of claim 1 wherein a average energy density emitted from the pulses on a per second basis within the wavelength band of between about 200 nm to about 400 nm is between about 400 J/s cm² to about 6,000 J/s cm².

10. The method of claim 1 wherein the radiation emitted from the pulses between the wavelengths of between about 200 to about 400 nanometers initiate curing of the dispensed material.

11. The method of claim 1 wherein the radiation emitting pulses each have a pulse width of between about 10 microseconds to about 4 milliseconds.

12. The method of claim 1 wherein the radiation emitting pulses each have a pulse width of between about 20 to about 200 microseconds.

13. The method of claim 1 wherein the radiation emitting pulses each have a pulse width of between about 70 to about 150 microseconds.

14. The method of claim 1 wherein the radiation emitting pulses each have a pulse width of between about 90 to about 100 microseconds.

15. The method of claim 1 wherein the at least one planar flash is applied for a duration having a duty cycle of less than 100%.

16. The method of claim 1 wherein the at least one planar flash is applied for a duration having a duty cycle between about 4.1% and about 25%.

17. The method of claim 1 wherein the at least one planar flash has a duration of between about 0.01 to about 2.0 seconds.

18. The method of claim 1 wherein the at least one planar flash has a duration of between about 0.5 to about 1.5 seconds.

19. The method of claim 1 wherein the at least one planar flash has a duration of about 1 second.

20. A selective deposition modeling apparatus for forming a three-dimensional object from a curable material in a build environment, the apparatus receiving data corresponding to layers of the three-dimensional object, the apparatus comprising:

a support means affixed to the apparatus for supporting the three-dimensional object in the build environment;

a dispensing means affixed to the apparatus and in communication with the support means for dispensing the curable material in the build environment according to the computer data to form the layers of the three-dimensional object; and

a flash exposure means affixed to the apparatus and in communication with the support means for exposing the dispensed material in the build environment to at least one planar flash of radiation, the planar flash comprising a plurality of radiation emitting pulses that initiate curing of the dispensed material.

21. The apparatus of claim 20 wherein the flash exposure means is connected to the dispensing means.

22. The apparatus of claim 20 wherein the support means reciprocates along a fixed path with respect to the dispensing means.

23. The apparatus of claim 20 wherein the flash exposure means and dispensing means are positioned above the support means.

24. The apparatus of claim 20 wherein between about 1 to about 15 joules of energy are needed for generating each radiation emitting pulse.

25. The apparatus of claim 20 wherein between about 1 to about 5 joules of energy are needed for generating each radiation emitting pulse.

26. The apparatus of claim 20 wherein about 3.5 to about 4.5 joules of energy is needed for generating each radiation emitting pulse.

27. The apparatus of claim 20 wherein the flash exposure means consumes less than about 1000 watts of power.

28. The apparatus of claim 20 wherein the flash exposure means consumes less than about 800 watts of power.

29. The apparatus of claim 20 wherein the flash exposure means consumes less than about 600 watts of power.

30. The apparatus of claim 20 wherein the flash exposure means consumes less than about 500 watts of power.

31. The apparatus of claim 20 wherein the radiation emitted from the pulses of the flash exposure means between the wavelengths of between about 200 to about 400 nanometers have a average energy density on a per second basis of between about 400 J/s cm² to about 6,000 J/s cm.

32. The apparatus of claim 20 wherein the radiation emitted from the pulses of the flash exposure means between the wavelengths of between about 200 to about 400 nanometers initiate curing of the dispensed material

33. The apparatus of claim 20 wherein the radiation emitting pulses generated by the flash exposure means each has a pulse width of between about 10 microseconds to about 4 milliseconds.

34. The apparatus of claim 20 wherein the radiation emitting pulses generated by the flash exposure means each have a pulse width of between about 20 to about 200 microseconds.

35. The apparatus of claim 20 wherein the radiation emitting pulses generated by the flash exposure means each have a pulse width of between about 90 to about 100 microseconds.

36. The apparatus of claim 20 wherein the flash exposure means has a duty cycle of less than 100%.

37. The apparatus of claim 20 wherein the flash exposure means has a duty cycle between about 4.1% and about 25%.

38. The apparatus of claim 20 wherein the at least one planar flash has a duration of between about 0.01 to about 2.0 seconds.

39. The apparatus of claim 20 wherein the at least one planar flash has a duration of between about 0.5 to about 1.5 seconds.

40. The apparatus of claim 20 wherein the at least one planar flash has a duration of about 1 second.

41. The apparatus of claim 20 wherein the flash exposure means comprises at least one lamp that emits the radiation, the lamp selected from the group consisting of a light-emitting-diode lamp, a microwave-powered lamp, a xenon lamp, a xenon-mercury lamp, a xenon-metal halide lamp, and combinations thereof.

42. The apparatus of claim 20 wherein the exposure means comprises a reflector housing assembly holding a xenon lamp which directs the at least one planar flash of radiation generated by the exposure means to expose a planar area of at least about 10 square inches in the build environment.

43. A flash curing system for a solid freeform fabrication apparatus that emits radiation to cure a build material dispensed by the apparatus in a build environment, the exposure system comprising:

at least one lamp for producing at least one planar flash comprising a plurality of radiation emitting pulses;

a pulse-forming network operably connected to the lamp for providing the excitation energy to the flash lamp to generate the plurality of radiation emitting pulses, the excitation energy for each radiation emitting pulse being between about 1 and about 15 joules at a direct current voltage of about 2250 volts or less;

a trigger operably connected between said lamp and the pulse-forming network for initiating delivery of the excitation energy from the pulse-forming network to the flash lamp to generate each pulse; and

a power supply operably connected to the pulse-forming network for initially supplying the excitation energy and re-supplying the excitation energy to the pulse-forming network prior to each pulse, the power supply consuming less than about 1000 watts of power.

44. The flash curing system of claim 43 wherein the excitation energy for each radiation emitting pulse is between about 1 to about 5 joules.

45. The flash curing system of claim 43 wherein the excitation energy for each radiation emitting pulse is between about 3.5 to about 4.5 joules.

46. The flash curing system of claim 43 wherein the excitation energy for each radiation emitting pulse is provided at a direct current voltage of about 1800 volts.

47. The flash curing system of claim 43 wherein the power supply consumes less than about 800 watts.

48. The flash curing system of claim 43 wherein the power supply consumes less than about 600 watts.

49. The flash curing system of claim 43 wherein the power supply consumes less than about 800 watts.

50. The flash curing system of claim 43 wherein a average energy density emitted from the pulses on a per second basis within the wavelength band of between about 200 nm to about 400 nm is between about 400 J/s cm² to about 6,000 J/s cm².

51. The flash curing system of claim 43 wherein the plurality of pulses emitted from the lamp have a pulse width of between about 10 microseconds to about 4 milliseconds.

52. The flash curing system of claim 43 wherein the plurality of pulses emitted from the lamp have a pulse width of between about 20 to about 200 microseconds.

53. The flash curing system of claim 43 wherein the plurality of pulses emitted from the lamp have a pulse width of between about 70 to about 150 microseconds.

54. The flash curing system of claim 43 wherein the plurality of pulses emitted from the lamp have a pulse width of between about 90 to about 100 microseconds.

55. The flash curing system of claim 43 wherein the at least one planar flash has a duration of between about 0.01 to about 2.0 seconds.

56. The flash curing system of claim 43 wherein the at least one planar flash has a duration of between about 0.5 to about 1.5 seconds.

57. The flash curing system of claim 43 wherein the at least one planar flash has a duration of about 1 second.

58. The flash curing system of claim 43 further comprising:

a reflector housing assembly containing the lamp for forming and directing the planar flash of radiation at a desired area in the build environment of the apparatus.

59. The flash curing system of claim 58 wherein the desired area is at least about ten square inches.

60. The flash curing system of claim 43 wherein the lamp is selected from the group consisting of a light-emitting-diode lamp, a microwave-powered lamp, a xenon lamp, a xenon-mercury lamp, a xenon-metal halide lamp, and combinations thereof.