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

• US 6,129,884 A
• Filed: 02/08/1999
• Issued: 10/10/2000
• 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., Chari, Arvind, Tang, Nansheng
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US09/246,501
• Time in Patent Office: 610 Days
• Field of Search: 264/40.1, 264/308, 264/401, 264/406, 425/135, 425/174.4, 425/375, 700/120, 359/245, 359/285, 372/12, 372/13, 372/81
• 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

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 including a power adjustment device;

specifying a desired power level for the beam of prescribed stimulation;

sensing the power of the beam of prescribed stimulation by directing the beam temporarily onto a sensor;

sending a control signal to the power adjustment device based on the desired power level and on sensing the actual power of the beam;

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.

2. The method of claim 1 wherein the source of prescribed stimulation comprises a solid state laser having a resonator and the power adjustment device is an AOM located outside the resonator.

3. The method of claim 2 wherein the prescribed stimulation is produced by a solid state laser in combination with at least one frequency conversion device and the AOM is located between the laser resonator and the at least one frequency conversion device.

4. 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 including a power adjustment device;

a memory for holding a desired power level for the beam of prescribed stimulation;

a sensor for sensing the power of the beam of prescribed stimulation when the beam is temporarily directed onto the sensor;

a generator for producing a control signal for controlling the power adjustment device based on the desired power level and on the sensed power of the beam;

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

an exposure system for exposing the material to the beam of prescribed stimulation to form the subsequent lamina of the object; and

a computer programmed to control the coating system and exposure system to form the object from a plurality of adhered laminae.

5. The apparatus of claim 4 wherein the source of prescribed stimulation comprises a solid state laser having a resonator and the power adjustment device is an AOM located outside the resonator.

6. The apparatus of claim 4 wherein the prescribed stimulation is produced by a solid state laser in combination with at least one frequency conversion device and the AOM is located between laser resonator and the at least one frequency conversion device.

7. 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:

means for producing a beam of prescribed stimulation including a power adjustment device;

means for specifying a desired power level for the beam of prescribed stimulation;

means for detecting the power of the beam of prescribed stimulation when the beam is temporarily directed onto the means for detecting;

means for producing a control signal for controlling the power adjustment device based on the desired power level and on sensing the actual power of the beam;

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

means for exposing the material to the beam of prescribed stimulation to form the subsequent lamina of the object; and

means for controlling the coating system and exposure system to form the object from a plurality of adhered laminae.

8. 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 including a laser source and a power adjustment device;

specifying a desired power level for the beam of prescribed stimulation;

determining the power in the beam of prescribed stimulation;

sending a control signal to the power adjustment device based on the desired power level and on the determined power of the beam;

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 power adjustment device comprises one 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.