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

• US 6,241,934 B1
• Filed: 02/08/1999
• Issued: 06/05/2001
• 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: Beers, Ross D., Everett, Michael A.
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US09/247,120
• Time in Patent Office: 848 Days
• Field of Search: 264/401, 425/135, 425/174.4, 425/375, 700/120
• US Class Current: 264/401
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• 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
• CPC Class Codes: G05B 19/4099 Surface or curve machining, making 3D objects, e.g. desktop manufacturing

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; 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 reduce or completely stop the source of prescribed stimulation so as to reduce or stop the output power during production of the prescribed stimulation, while forming the object, for at least a portion of at least one period of time when the prescribed stimulation is not needed for exposing the material.

2. The method of claim 1 wherein the production of prescribed stimulation is stopped during the at least one period of time.

3. The method of claim 1 wherein the production of prescribed stimulation is reduced by at least 50%.

4. The method of claim 1 wherein the production of prescribed stimulation is reduced by at least 75%.

5. The method of claim 1 wherein the production of prescribed stimulation is reduced by at least 90%.

6. The method of claim 1 wherein the source 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.

7. The method of claim 6 wherein the inhibiting device is used to block the radiation of the first wavelength from reaching the frequency conversion element during the period when production of prescribed stimulation is to be reduced.

8. The method of claim 6 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.

9. The method of claim 6 wherein the inhibiting device is an acousto-optic modulator.

10. The method of claim 9 wherein the at least one period of reduced prescribed stimulation includes a period of time during the formation of each of a plurality of layers.

11. 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; and

a computer programmed to repeatedly operate the recoating system to form the object from a plurality of adhered laminae,

wherein the source of prescribed stimulation is controlled to reduce or completely stop the source of prescribed stimulation so as to reduce or stop the output power during production of the prescribed stimulation, while forming the object, for at least a portion of one period of time when the prescribed stimulation is not needed for exposing the material.

12. The apparatus of claim 11 wherein the computer controls the source of prescribed stimulation and stops the production of prescribed stimulation during at least a portion of the at least one period of time.

13. The apparatus of claim 11 wherein the source 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.

14. The apparatus of claim 13 wherein the inhibiting device is configured to block the radiation of the first wavelength from reaching the frequency conversion element during the period when production of prescribed stimulation is to be reduced.

15. The apparatus of claim 13 wherein the at least one frequency conversion element comprises first and second conversion elements, wherein the first element converts the radiation of the first wavelength to radiation of a second wavelength and then the second element converts the radiation of the second wavelength into the prescribed stimulation.

16. The apparatus of claim 13 wherein the inhibiting device is an acousto-optic modulator.

17. The apparatus of claim 16 wherein the accousto-optic modulator is controlled by the computer to reduce the prescribed stimulation during at least a portion of a period used in forming each of a plurality of layers.