Rapid prototyping and tooling system

• US 6,405,095 B1
• Filed: 05/25/1999
• Issued: 06/11/2002
• Est. Priority Date: 05/25/1999
• Status: Expired due to Term

• Current Assignee: Nanotek Instruments Group, LLC
• Original Assignee: Nanotek Instruments, Inc.
• Inventors: Lu, Xin, Duan, Jun, Ma, Erjian, Chen, Kerbin, Jang, Borzeng
• Primary Examiner(s): PATEL, RAMESH B
• Application Number:
  US09/318,779
• Time in Patent Office: 1,113 Days
• Field of Search: 700/97, 700/98, 700/117, 700/118, 700/119, 700/163, 345/419, 345/420, 264/75, 264/401, 264/308, 264/633, 264/642, 427/466, 427/472, 427/470
• US Class Current: 700/118
• CPC Class Codes: B22F 1/00 Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
• CPC Class Codes: B22F 10/22 Direct deposition of molten metal
• CPC Class Codes: B22F 10/25 Direct deposition of metal particles, e.g. direct metal deposition [DMD] or laser engineered net shaping [LENS]
• CPC Class Codes: B22F 10/80 Data acquisition or data processing
• CPC Class Codes: B22F 12/33 translatory in the deposition plane
• CPC Class Codes: B22F 12/53 Nozzles
• CPC Class Codes: B22F 12/55 Two or more means for feeding material
• CPC Class Codes: B22F 12/57 Metering means
• CPC Class Codes: B22F 12/58 for changing the material composition, e.g. by mixing
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• CPC Class Codes: B29C 64/165 using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber
• 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 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: G05B 19/4099 Surface or curve machining, making 3D objects, e.g. desktop manufacturing
• CPC Class Codes: G05B 2219/49018 Laser sintering of powder in layers, selective laser sintering SLS
• CPC Class Codes: Y02P 10/25 Process efficiency
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A solid freeform fabrication process and apparatus for making a three-dimensional object. The process comprises the steps of (1) operating a material deposition sub-system for dispensing droplets of solidifiable liquid compositions on demand onto selected spots of an object work surface, for using a focused heat source to maintain a heat-affected zone on the work surface, and for creating a weld pool of molten materials on this work surface by injecting selected powder particles into this heat-affected zone and (2) during the material deposition process, moving the deposition sub-system and the work surface relative to each other in an X-Y plane defined by first and second directions and in a Z direction orthogonal to the X-Y plane so that the materials are deposited to form a first layer of the object. The material in the weld pool solidifies after the heat-affected zone moves away to build portions of a layer. These steps are repeated to deposit multiple layers for forming a three-dimensional shape. Preferably, the peripheral areas and the staircase step zones between layers are built with fine droplets for improved part accuracy while the bulk of the object is built with solidification of weld pool materials. These steps are preferably executed under the control of a computer system. Preferably, the system is also operated to generate a support structure for any un-supported feature of the object.

Claims

1. Solid freeform fabrication apparatus for making a three-dimensional object, comprising:

(a) a work surface;

(b) a material deposition sub-system, disposed above and in working proximity to said work surface, comprising;

a liquid droplet deposition device comprising (1) a multiplicity of flow channels with each channel being supplied with a solidifiable liquid composition, (2) at least one nozzle having, on one end, a fluid passage in flow communication with one of said multiple channels and, on another end, a discharge orifice of a predetermined size, and (3) actuator means located in control relation to said channels for activating ejection of droplets through said discharge orifice;

a focused heat source disposed in working proximity to said work surface and operative to produce a heat-affected zone on said work surface;

a powder-dispensing device, disposed in close proximity to said liquid droplet deposition device, comprising (1) at least a flow channel being supplied with solid powder particles, (2) at least one nozzle having, on one end, a flow passage in flow communication with said flow channel and, on another end, a discharge orifice of a predetermined size, and (3) valve means located in control relation with said flow channel and operative to inject solid powder particles to said heat-affected zone for forming a weld pool of molten material;

(c) motion devices coupled to said work surface and said material deposition sub-system for moving said deposition sub-system and said work surface relative to one another in a plane defined by first and second directions and in a third direction orthogonal to said plane to form said liquid droplets and weld pool material, collectively referred to as deposition materials, into a three-dimensional shape.

2. Apparatus as set forth in claim 1, wherein said focused heat source comprises a laser beam.

3. Apparatus as set forth in claim 1, wherein said liquid droplet deposition device comprises an ink jet print-head.

4. Apparatus as set forth in claim 1, wherein said multiplicity of channels are embodied in a plurality of separate droplet deposition devices with each of said devices having at least a channel being supplied with a liquid composition from a liquid reservoir through a pipe means.

5. Apparatus as set forth in claim 1, further comprising:

a computer-aided design computer and supporting software programs operative to create a three-dimensional image of a desired object, to convert said image into a plurality of segments defining the object, and to generate programmed signals corresponding to each of said segments in a predetermined sequence; and

a three-dimensional machine controller electronically linked to said computer and said motion devices and operative to actuate said motion devices in response to said programmed signals for each of said segments received from said computer.

6. Apparatus as set forth in claim 5, wherein said supporting software programs comprises:

means for evaluating the data files representing the image of said object to locate any un-supported feature of the object;

means, responsive to the evaluating means locating an un-supported feature, for defining a support structure for said un-supported feature;

means for creating a plurality of segments defining said support structure; and

means for generating programmed signals required by said material deposition sub-system to fabricate said support structure.

7. Apparatus as set forth in claim 5, further comprising:

sensor means electronically linked to said computer and operative to periodically provide layer dimension data to said computer;

supporting software programs in said computer operative to perform adaptive layer slicing to periodically create a new set of layer data comprising segments defining the object in accordance with said layer dimension data acquired by said sensor means, and to generate programmed signals corresponding to each of said segments in a predetermined sequence.

8. Apparatus as set forth in claim 1 wherein said powder-dispensing device comprises a multi-channel pneumatic plug-phase delivery device comprising:

multiple powder-supplying chambers;

pipe means in flow communication with said chambers to receive plugs of powder material therefrom;

a supply of compressed air and valve means in control relation to said chambers and said pipe means to create said plugs of material on demand in said pipe means;

a dispensing nozzle having, on one end, a flow passage in flow communication with said pipe means and, on another end, a discharge orifice of a predetermined size to dispense said powder material therethrough.

9. A solid freeform fabrication process for making a three-dimensional object comprising the steps of:

positioning a material deposition sub-system a selected distance above a work surface;

operating said sub-system to deposit materials onto said work surface comprising the steps of (a) operating a multiple-channel liquid droplet deposition device of said deposition sub-system for supplying and ejecting multiple liquid compositions in a droplet form on demand onto selected spots of said work surface;

(b) operating a focused heat source to produce a heat-affected zone on said work surface; and

(c) operating a solid powder-dispensing device for discharging selected powder particles to said heat-affected zone for forming a molten weld pool of a predetermined size;

said (a), (b), and (c) steps being operated in a predetermined sequence;

during said material deposition process, moving said deposition sub-system and said work surface relative to one another in a plane defined by first and second directions and in a third direction orthogonal to said plane to form said liquid droplets and weld pool material into a three dimensional shape.

10. A process as set forth in claim 9, wherein the moving step includes the steps of:

moving said deposition sub-system and said work surface relative to one another in a direction parallel to said plane to form a first layer of said liquid droplets and weld pool materials on said work surface;

said droplets and said weld pool materials being hereinafter collectively referred to as deposition materials;

moving said material deposition sub-system and said work surface away from one another in said third direction by a predetermined layer thickness; and

after the portion of said first layer adjacent to said deposition sub-system has substantially solidified, dispensing and depositing a second layer of said deposition materials onto said first layer while simultaneously moving said work surface and said deposition sub-system relative to one another in a direction parallel to said plane, whereby said second layer solidifies and adheres to said first layer.

11. A process as set forth in claim 10, comprising additional steps of forming multiple layers of said deposition materials on top of one another by repeated dispensing and depositing of said deposition materials from said deposition sub-system as said work surface and said deposition sub-system are moved relative to one another in a direction parallel to said plane, with said deposition sub-system and said work surface being moved away from one another in said third direction by a predetermined layer thickness after each preceding layer has been formed and with the depositing of each successive layer being controlled to take place after said deposition materials in the preceding layer immediately adjacent said deposition sub-system have substantially solidified.

12. A process as set forth in claim 9, further comprising the steps of:

creating an image of said three-dimensional object on a computer with said image including a plurality of segments defining the object;

generating programmed signals corresponding to each of said segments in a predetermined sequence; and

moving said deposition sub-system and said work surface relative to each other in response to said programmed signals.

13. A process as set forth in claim 9, further comprising the steps of:

creating an image of said three-dimensional object on a computer with said image including a plurality of segments defining the object;

each of said segments being coded with a selected material composition corresponding to one or more types of material combined at a predetermined proportion;

generating programmed signals corresponding to each of said segments in a predetermined sequence;

operating said material deposition sub-system in response to said programmed signals to selectively dispense and deposit said selected deposition materials;

moving said deposition sub-system and said work surface relative to one another in response to said programmed signals.

14. A process as set forth in claim 9, wherein said moving step includes the step of moving said deposition sub-system and said work surface relative to one another in a direction parallel to said plane according to a first predetermined pattern to form an outer boundary from selected liquid compositions on said work surface, said outer boundary defining an exterior surface of said object.

15. A process as set forth in claim 14, wherein said outer boundary defines an interior space in said object, and said moving step further includes the step of moving said deposition sub-system and said work surface relative to one another in one direction parallel to said plane according to at least one other predetermined pattern to fill said interior space with selected deposition materials.

16. A process as set forth in claim 15, further comprising the steps of:

creating an image of said three-dimensional object on a computer, said image including a plurality of segments defining said object; and

generating program signals corresponding to each of said segments in a predetermined sequence, wherein said program signals determine said movement of said deposition sub-system and said work surface relative to one another in said first predetermined pattern and said at least one other predetermined pattern.

17. A process as set forth in claim 15 wherein said interior space is deposited with a spatially controlled material composition comprising two or more distinct types of materials.

18. A process as set forth in claim 17 wherein said interior space is deposited with a material composition in continuously varying concentrations of distinct materials in three-dimensional part space to form a spatially controlled material composition part.

19. A process as set forth in claim 17 wherein said distinct types of materials are deposited at discrete locations in three-dimensional part space to form a spatially controlled material composition part.

20. A process as set forth in claim 9, further comprising:

using dimension sensor means to periodically measure dimensions of the object being built;

using a computer to determine the thickness and outline of individual layers of said deposition materials in accordance with a computer aided design representation of said object;

said computing step comprising operating said computer to calculate a first set of logical layers with specific thickness and outline for each layer and then periodically re-calculate another set of logical layers after periodically comparing the dimension data acquired by said sensor means with said computer aided design representation in an adaptive manner.

21. A process as set forth in claim 9, further comprising the steps of:

creating an image of said three-dimensional object on a computer with said image including a plurality of segments defining the object;

evaluating the data files representing said object to locate any un-supported feature of the object and, responsive to said evaluation step, determining a support structure for the un-supported feature and creating a plurality of segments defining said support structure;

generating program signals corresponding to each of said segments for both said object and said support structure in a predetermined sequence;

moving said deposition sub-system and said work surface relative to each other in response to said programmed signals for building said object and said support structure.

22. A process as set forth in claim 9, further comprising the steps of:

creating an image of said three-dimensional object on a computer with said image including a plurality of segments defining the object;

evaluating the data files representing said object to locate any un-supported feature of the object and, responsive to said evaluation step, determining a support structure for the un-supported feature and creating a plurality of segments defining said support structure;

each of said segments for the object and the support structure being coded with a selected material composition corresponding to one or more types of material combined at a predetermined proportion;

generating programmed signals corresponding to each of said segments in a predetermined sequence;

operating said material deposition sub-system in response to said programmed signals to selectively dispense and deposit said selected deposition materials; and

moving said deposition sub-system and said work surface relative to one another in response to said programmed signals for building said object and said support structure.

24. A process as set forth in claim 9, wherein a peripheral zone of said object is built by depositing ejected fine droplets of selected liquid compositions.

25. A process as set forth in claim 9, wherein a staircase zone of said object is deposited with ejected fine droplets of selected liquid compositions in a gradient-thickness fashion for improved part accuracy.

26. A process as set forth in claim 12, 13, 20, 21, 22, or 23, wherein a staircase zone of said object is deposited with ejected fine droplets of selected liquid compositions in a gradient-thickness fashion for improved part accuracy.

27. A process as set forth in claim 12, 13, 20, 21, 22, or 23, wherein said object is composed of a multiplicity of layers including a first layer and a final layer and wherein the final layer of said object is built primarily with fine droplets of selected liquid compositions for improved accuracy.

28. A process as set forth in claim 12, 13, 20, 21, 22, or 23, wherein a peripheral zone of said object is built by depositing ejected fine droplets of selected liquid compositions.

23. A process for making a multi-material three-dimensional object, comprising the steps of:

creating an image of said three-dimensional object on a computer, said image including a plurality of segments defining said object;

evaluating the data files representing said object to locate any un-supported feature of the object, followed by defining a support structure for the un-supported feature and creating a plurality of segments defining said support structure;

generating program signals corresponding to each of said segments for both said object and said support structure in a predetermined sequence;

providing a supply of selected liquid compositions and weld pool materials;

operating a material deposition sub-system to deposit selected materials onto a work surface;

said deposition step comprising ejecting said liquid compositions in a droplet form onto desired spots of said work surface and introducing a weld pool of molten materials on said work surface;

during said deposition step, moving said deposition sub-system and said work surface in response to said programmed signals relative to one another in a plane defined by first and second directions and in a third direction orthogonal to said plane in a predetermined sequence of movements such that said deposition materials are deposited in free space as a plurality of segments sequentially formed so that the last deposited segment overlies at least a portion of the preceding segment in contact therewith to thereby form said support structure and said three-dimensional object on said work surface;

removing said support structure from said work surface.