Thermal stereolithography

• US 5,501,824 A
• Filed: 11/08/1993
• Issued: 03/26/1996
• Est. Priority Date: 04/18/1988
• Status: Expired due to Term

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Inventors: Smalley, Dennis R., Almquist, Thomas A.
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US08/148,544
• Time in Patent Office: 869 Days
• Field of Search: 264/22, 264/40.1, 264/40.7, 264/221, 264/236, 264/255, 264/308, 425/135, 425/145, 425/147, 425/174.4, 156/64, 156/272.8, 156/273.3, 156/273.5, 156/275.5, 156/307.1, 156/378, 156/379.6, 156/538, 427/8, 427/356, 427/358, 427/393.5, 427/412.1, 427/557, 427/561, 118/100, 118/120, 118/407, 118/413, 118/421, 118/423, 118/428, 118/429, 118/620, 118/693, 118/694, 118/720, 222/55, 222/145, 222/146.2, 250/432 R, 250/492.1, 364/468, 364/476, 395/119
• US Class Current: 264/401
• CPC Class Codes: B29C 41/12 Spreading-out the material on a substrate , e.g. on the surface of a liquid
• CPC Class Codes: B29C 41/36 Feeding the material on to the mould, core or other substrate
• CPC Class Codes: B29C 64/124 using layers of liquid which are selectively solidified
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29C 64/141 using only solid materials
• CPC Class Codes: B29C 64/40 Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• 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: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: B33Y 40/10 Pre-treatment
• CPC Class Codes: B33Y 40/20 Post-treatment, e.g. curing, coating or polishing
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• CPC Class Codes: G03F 7/70375 Multiphoton lithography or multiphoton photopolymerization; Imaging systems comprising means for converting one type of radiation into another type of radiation
• CPC Class Codes: G05B 2219/49013 Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
• CPC Class Codes: G05B 2219/49015 Wire, strang laying, deposit fluid, welding, adhesive, hardening, solidification, fuse
• CPC Class Codes: G05B 2219/49039 Build layer of different, weaker material between support and prototype

Abstract

Apparatus for and related methods of forming three-dimensional objects out of a building material, which is normally solid but which is flowable when heated. In one embodiment a support material is used to fill in portions of layers which are not to be solidified as part of the object to provide support to otherwise unsupported portions of other layers. Advantageously, the support material is also normally solid and flowable when heated, and has a lower melting point than the building material enabling the support material to later be removed without damaging the object. In an alternative embodiment this support material can be used to build a support such as a web support, or the like, for supporting an object surface from a second surface. In another alternative embodiment such an apparatus is combined with a conventional stereolithographic apparatus to provide means for forming an object out of conventional stereolithographic materials, but utilizing a normally solid but thermally-flowable support material to provide support to the object, either on a layer-by layer basis, or by building supports such as web supports.

Claims

1. An apparatus for forming a three-dimensional object, comprising:

a building chamber within which the three-dimensional object is formed, for containing one of a building material and a support material which is capable of physical transformation upon exposure to synergistic stimulation, the building chamber being maintained at a temperature below a flowable temperature;

a container for containing the other one of the building material and support material comprising material which is normally solid but flowable when maintained at or above the flowable temperature;

a heater for maintaining the normally solid material at or above the flowable temperature thereby forming flowable material;

a nozzle coupled to the container for selectively dispensing a flow of the flowable material into the building chamber;

a computer coupled to the apparatus and programmed to transmit control signals;

a flow controller coupled to the nozzle and responsive to control signals, for controlling the flow of the flowable material into the building chamber;

a positioner responsive to control signals, for relatively positioning the nozzle and the three-dimensional object being formed;

an exposer positioned in proximity to the building chamber and responsive to control signals, for exposing the material contained in the building chamber;

wherein control signals are sent to the flow controller and the positioner to selectively dispense the flow of the flowable material according to a prescribed pattern, the pattern specifying at least one region where building material is to be located and at least one region where support material is to be located; and

wherein control signals are sent to the exposer to expose the material contained within the building chamber.

2. The apparatus of claim 1 wherein the computer is further programmed to transmit control signals to form the three-dimensional object substantially layer-by-layer.

3. The apparatus of claim 2 wherein the exposer selectively exposes the material capable of physical transformation upon exposure to synergistic stimulation.

4. A method for forming a three-dimensional object, comprising the steps of:

maintaining a building chamber within which the three-dimensional object is formed, at a temperature below a flowable temperature;

containing one of a building material and a support material which is capable of physical transformation upon exposure to synergistic stimulation in the building chamber;

containing the other one of the building material and support material comprising material which is normally solid but flowable when maintained at or above the flowable temperature in a container;

maintaining the normally solid material in the container at or above the flowable temperature thereby forming flowable material;

relatively positioning the nozzle and the three-dimensional object being formed;

selectively dispensing a flow of the flowable material into the building chamber according to a prescribed pattern, the pattern specifying at least one region where building material is to be located and at least one region where support material is to be located;

exposing the material contained in the building chamber; and

repeating the positioning, dispensing and exposing steps to form the object.

5. The method of claim 4 further comprising the step of:

forming the three-dimensional object substantially layer-by-layer.

6. The method of claim 5 wherein the step of exposing transforms the building material.

7. The method of claim 5 wherein the step of exposing transforms the support material.

8. The method of claim 5 wherein the step of exposing selectively exposes the material capable of physical transformation upon exposure to synergistic stimulation.

9. An apparatus for forming a three-dimensional object substantially layer-by-layer from a building material comprising a material normally solid but flowable when maintained at or above a first flowable temperature, and a support material comprising a material normally solid but flowable when maintained at or above a second flowable temperature, comprising:

a first container for containing the building material;

a second container for containing the support material;

a building chamber positioned in proximity to the first and second containers, the building chamber being maintained at a temperature below the first and second flowable temperatures;

at least one heater for maintaining the building material at or above the first flowable temperature thereby forming flowable building material, and maintaining the support material at or above the second flowable temperature thereby forming flowable support material;

at least one nozzle coupled to the first and second containers for selectively dispensing a flow of the flowable building material and a flow of the flowable support material into the building chamber;

a computer coupled to the apparatus and programmed to transmit control signals;

at least one flow controller coupled to the at least one nozzle and responsive to control signals, for controlling the flow of the flowable building material and the flow of the flowable support material into the building chamber;

a positioner responsive to control signals for relatively positioning the at least one nozzle and the building chamber; and

wherein control signals are sent to the at least one flow controller and the positioner to dispense the flow of the flowable building material and the flow of the flowable support material according to a prescribed pattern to form successive layers, the pattern specifying at least one region where support material is selectively dispensed instead of building material.

10. The apparatus of claim 9 wherein the at least one nozzle dispenses the flowable support material before dispensing the flowable building material for a given layer of the object.

11. The apparatus of claim 9 further comprising:

a heater for heating the three-dimensional object after it is formed to a temperature below the first flowable temperature and at or above the second flowable temperature to remove the support material from the three-dimensional object.

12. A method for forming a three-dimensional object substantially layer-by-layer from a building material comprising a material normally solid but flowable when maintained at or above a first flowable temperature, and a support material comprising a material normally solid but flowable when maintained at or above a second flowable temperature, comprising the steps of:

containing the building material in a first container;

containing the support material in a second container;

maintaining a building chamber at a temperature below the first and second flowable temperatures;

providing at least one nozzle coupled to the first and second containers through which the flowable building material and the flowable support material may be dispensed;

heating the building material to a temperature at or above the first flowable temperature thereby forming flowable building material;

heating the support material to a temperature at or above the second flowable temperature thereby forming flowable support material;

relatively positioning the at least one nozzle and the building chamber;

selectively dispensing a flow of the flowable building material and a flow of the flowable support material through the at least one nozzle and into the building chamber according to a prescribed pattern, the pattern specifying at least one region where support material is selectively dispensed instead of building material; and

repeating the positioning and dispensing steps to form the object.

13. The method of claim 12 wherein the flowable support material is dispensed before the flowable building material for a given layer of the object.

14. The method of claim 12 further comprising the step of:

heating the three-dimensional object after it is formed to a temperature below the first flowable temperature and at or above the second flowable temperature to remove the support material from the three-dimensional object.

15. The apparatus of claim 2, further comprising a recoater for forming coatings of the material contained by the building chamber over previously formed layers of the three-dimensional object in preparation for exposing successive layers of the material contained by the building chamber.

16. The apparatus of claim 15, further comprising a source of synergistic stimulation which provides electromagnetic radiation and wherein the material contained by the building chamber is a photopolymer.

17. The apparatus of claim 15 wherein the computer is programmed to selectively dispense the flowable material on a given layer prior to forming the coating of material contained by the building chamber, wherein the material contained by the building chamber is the building material.

18. The apparatus of claim 17 wherein the recoater comprises a squeegee for wiping off excess building material from the previously dispensed support material prior to exposing the building material for the given layer.

19. The method of claim 5 wherein the step of repeating further comprises the steps of:

forming a coating of the material contained by the building chamber over a previously formed layer of the three-dimensional object in preparation for exposing the coating to synergistic stimulation; and

repeating the positioning, dispensing, exposing, and forming steps to form the object.

20. The method of claim 19 wherein the synergistic stimulation is electromagnetic radiation and wherein the material contained by the building chamber is a photopolymer.

21. The method of claim 19 wherein the step of dispensing for a given layer occurs prior to the step of forming a coating for the given layer.

22. The method of claim 21 wherein the building material is the material contained by the building chamber, and the step of forming a coating comprises wiping off excess building material from the previously dispensed material with a squeegee prior to exposing the building material for the given layer.

23. An apparatus for forming a three-dimensional object on a substantially cross-section-by-cross-section basis, comprising:

a container for containing a building material which is normally in a solid state and which is made flowable when maintained at or above a first flowable temperature;

a heater for maintaining the building material at or above the first flowable temperature thereby forming flowable building material;

a building chamber maintained at a temperature below the first flowable temperature;

a dispenser coupled to the container, and responsive to positioning control signals, and adapted to selectively dispense the flowable building material into the building chamber in accordance with the positioning control signals; and

a computer programmed to identify for at least one cross-section, supported object portions which are supported by a previous cross-section and unsupported object portions which are unsupported by a previous cross-section, the computer being further programmed to transmit positioning control signals to the dispenser such that building material is dispensed from a supported object portion to an unsupported object portion so that intercross-sectional horizontal adhesion of successively dispensed quantities of building material is used to support vertically unsupported regions of the cross-section during formation of the cross-section.

24. The apparatus of claim 23, wherein the building material is dispensed as a flow of building material.

25. The apparatus of claim 1, wherein the container is further adapted to maintain the normally solid material PG,38 contained therein at a temperature at or above the flowable temperature.

26. The method of claim 4, further comprising the step of maintaining the normally solid material contained by the container at a temperature at or above the flowable temperature.

27. The apparatus of claim 9, wherein the first container is further adapted to maintain the normally solid building material at a temperature at or above the first flowable temperature and wherein the second container is further adapted to maintain the normally solid support material at a temperature at or above the second flowable temperature.

28. The method of claim 12, further comprising the step of maintaining the normally solid building material in the first container at a temperature at or above the first flowable temperature and the step of maintaining the normally solid support material in the second container at a temperature at or above the second flowable temperature.

29. A method for forming a three-dimensional object on a substantially cross-section-by-cross-section basis, comprising:

containing a building material which is normally in a solid state and which is made flowable when maintained at or above a first flowable temperature;

maintaining the building material at or above the first flowable temperature thereby forming flowable building material;

maintaining a building chamber, for building the three-dimensional object, at a temperature below the first flowable temperature;

selectively dispensing the flowable building material from a dispenser coupled to the container into the building chamber in accordance with positioning control signals; and

programming a computer to identify, for at least one cross-section, supported object portions which are supported by a previous cross-section and unsupported object portions which are unsupported by a previous cross-section, the computer being further programmed to transmit positioning control signals to the dispenser such that building material is dispensed from a supported object portion to an unsupported object portion so that intercross-sectional horizontal adhesion of successively dispensed quantities of building material is used to support vertically unsupported regions of the cross-section during formation of the cross-section.

30. The method of claim 29 wherein the step of selectively dispensing further comprises selectively dispensing the flowable building material as a flow of building material.