Stereolithographic method and apparatus with enhanced control of prescribed stimulation and application

• US 6,325,961 B1
• Filed: 02/08/1999
• Issued: 12/04/2001
• Est. Priority Date: 02/08/1999
• Status: Expired due to Term

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Inventors: Partanen, Jouni P., Beers, Ross D., Tang, Nansheng
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US09/246,502
• Time in Patent Office: 1,030 Days
• Field of Search: 264/308, 264/401, 264/497, 425/135, 425/174.4, 425/375, 700/119, 700/120
• US Class Current: 264/401
• CPC Class Codes: B29C 2035/0838 using laser
• CPC Class Codes: B29C 64/40 Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• CPC Class Codes: B29K 2105/243 Partially cured
• CPC Class Codes: B29K 2995/0073 smooth
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor

Abstract

A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for producing three-dimensional objects by selectively subjecting a liquid or other fluid-like material to a beam of prescribed stimulation. In a preferred embodiment a source of prescribed stimulation is controlled to reduce or inhibit the production of the prescribed stimulation during at least some periods when the prescribed stimulation is not needed to expose the material. In another preferred embodiment, the source of stimulation is controlled to vary the quantity of prescribed stimulation that is produced and allowed to reach the material. In an additional preferred embodiment control of laser output occurs based on a combination of supplying a regulated amount of voltage to an AOM in conjunction with temporary sensing of laser power and a known desired power to attain. In a further preferred embodiment, a quantity of prescribed stimulation may be set by consideration of desired solidification depths to be used, beam profile characteristics, material properties, and scanning speed limitations for different data types. In a still further preferred embodiment, a transition between selected consecutive exposure vectors is performed by scanning one or more interposed non-exposure vectors with the beam inhibited from reaching the building material.

Claims

1. A method of forming a three-dimensional object from a plurality of adhered laminae by exposing successive layers of a material to a beam of prescribed stimulation, comprising:

providing a controllable source of a beam of prescribed stimulation;

forming a layer of material adjacent to any last formed layer of material in preparation for forming a subsequent lamina of the object;

exposing the material to the beam of prescribed stimulation to form the subsequent lamina of the object according to vector data descriptive of the subsequent lamina; and

repeating the acts of forming and exposing a plurality of times in order to form the object from a plurality of adhered laminae,

wherein the source of prescribed stimulation is controlled to provide one quantity of prescribed stimulation in the beam when exposing the material according to a first set of exposure vectors and another quantity of prescribed stimulation when exposing the material to a second set of exposure vectors.

2. The method of claim 1 wherein the first set of exposure vectors is used in exposing at least a portion of a first layer and wherein the second set of exposure vectors is used in exposing at least a portion of a second layer of material, where the first and second layers are located at different cross-sectional levels in the object.

3. The method of claim 1 wherein the controllable source of the beam of prescribed stimulation comprises:

a source of a first wavelength of radiation, wherein the radiation is directed along an optical path;

a beam inhibiting device located along the optical path;

at least one frequency conversion element located along the optical path for converting the radiation of the first wavelength to the prescribed stimulation, wherein the inhibiting device is located at a position on the optical path intermediate to the source of the first wavelength of radiation and the at least one frequency conversion element.

4. The method of claim 3 wherein the inhibiting device is used to direct a varying quantity of radiation into the at least one frequency conversion element so as to allow production of a varying quantity of prescribed stimulation.

5. The method of claim 4 wherein the at least one frequency conversion element converts the radiation of the first wavelength to radiation of a second wavelength and then converts the radiation of the second wavelength into the prescribed stimulation.

6. The method of claim 4 wherein the inhibiting device is an acousto-optic modulator (AOM).

7. The method of claim 6 wherein the radiation is directed along the first order path to the AOM and then to the at least one frequency conversion element.

8. The method of claim 1 wherein the quantity of prescribed stimulation is varied between exposure of one or more of (1) boundary vectors and hatch vectors, (2) hatch vectors and fill vectors, and (3) boundary vectors and fill vectors.

9. The method of claim 1 wherein the source of prescribed stimulation is controlled to provide a plurality of different quantities of prescribed stimulation in the beam when exposing the material according to a plurality of different sets of exposure vectors.

10. The method of claim 1 wherein the quantity of prescribed stimulation is varied between formation of support structures and formation of object structures.

11. The method of claim 1 wherein the controllable source of prescribed stimulation comprises one or more of:

(1) a mechanism for variably supplying electric power to a laser diode source that supplies pumping energy to the laser source, (2) a mechanism for variably controlling operation of a Q-switch in the laser source, (3) an electro-optic modulator, (4) a mechanism for variably controlling a pulse repetition rate of the power in the beam, (5) a mechanism for controlling the temperature of a laser diode source that supplies pumping energy to the laser source, or (6) a mechanism for controlling a temperature of a frequency conversion crystal through which the beam from the laser source passes.

12. An apparatus for forming a three-dimensional object from a plurality of adhered laminae by exposing successive layers of a material to a beam of prescribed stimulation, comprising:

a controllable source of a beam of prescribed stimulation;

a recoating system to form a layer of material adjacent to any last formed layer of material in preparation for forming a subsequent lamina of the object;

a scanning system to selectively expose the material to the beam of prescribed stimulation to form the subsequent lamina of the object according to vector data descriptive of the subsequent lamina; and

a computer programmed to repeatedly operate the recoating system, the scanning system, and the beam of prescribed stimulation a plurality of times in order to form the object from a plurality of adhered laminae,

wherein software is programmed or hardware configured to provide one quantity of prescribed stimulation in the beam when operating the scanning system to expose the material according to a first set of exposure vectors and another quantity of prescribed stimulation to expose the material to a second set of exposure vectors.

13. The apparatus of claim 12 wherein the scanning system exposes the first set of exposure vectors in at least a portion of a first layer and exposes the second set of vectors in at least a portion of a second layer of material, where the first and second layers are located at different cross-sectional levels in the object.

14. The apparatus of claim 12 wherein the controllable source of the beam of prescribed stimulation comprises:

a source of a first wavelength of radiation, wherein the radiation is directed along an optical path;

a beam inhibiting device located along the optical path;

at least one frequency conversion element located along the optical path for converting the radiation of the first wavelength to the prescribed stimulation, wherein the beam inhibiting device is located at a position on the optical path intermediate to the source of the first wavelength of radiation and the at least one frequency conversion element.

15. The apparatus of claim 14 wherein the beam inhibiting device is used to direct a varying quantity of radiation into the at least one frequency conversion element so as to allow production of a varying quantity of prescribed stimulation.

16. The apparatus of claim 15 wherein the at least one frequency conversion element converts the radiation of the first wavelength to radiation of a second wavelength and then converts the radiation of the second wavelength into the prescribed stimulation.

17. The apparatus of claim 16 wherein the beam inhibitor device is an acousto-optic modulator (AOM).

18. The apparatus of claim 17 wherein the controllable source of the beam of radiation directs the radiation along the first order path to the AOM and then to the at least one frequency conversion element.

19. The apparatus of claim 12 wherein the software is programmed or the hardware is configured to select the first set of exposure vectors and second set of exposure vectors from one or more of (1) boundary vectors and hatch vectors, (2) hatch vectors and fill vectors, and (3) boundary vectors and fill vectors.

20. The apparatus of claim 12 wherein the source of prescribed stimulation is controlled to provide a plurality of different quantities of prescribed stimulation in the beam when exposing the material according to a plurality of different sets of exposure vectors.

21. The apparatus of claim 12 wherein the software is programmed or the hardware is configured to select the first set of exposure vectors and second set of exposure vectors from support structures and object structures.

22. The apparatus of claim 12 wherein the controllable source of prescribed stimulation comprises one or more of:

(1) a mechanism for variably supplying electric power to a laser diode source that supplies pumping energy to the laser source, (2) a mechanism for variably controlling operation of a Q-switch in the laser source, (3) an electro-optic modulator, (4) a mechanism for variably controlling a pulse repetition rate of the power in the beam, (5) a mechanism for controlling the temperature of a laser diode source that supplies pumping energy to the laser source, or (6) a mechanism for controlling a temperature of a frequency conversion crystal through which the beam from the laser source passes.