Layer-additive method and apparatus for freeform fabrication of 3-D objects

• US 6,471,800 B2
• Filed: 11/29/2000
• Issued: 10/29/2002
• Est. Priority Date: 11/29/2000
• Status: Expired due to Fees

• Current Assignee: Nanotek Instruments Group, LLC
• Original Assignee: Nanotek Instruments, Inc.
• Inventors: Jang, Bor Z., Ma, Erjian
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Haran, John T.
• Application Number:
  US09/726,185
• Publication Number:
  US 20020062909A1
• Time in Patent Office: 699 Days
• Field of Search: 156/58, 156/155, 156/305, 156/307.1, 156/307.3, 156/390, 156/538, 156/578, 264/401, 427/256
• US Class Current: 156/58
• CPC Class Codes: B29C 64/147 using sheet material, e.g. laminated object manufacturing [LOM] or laminating sheet material precut to local cross sections of the 3D object
• 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 64/321 Feeding
• CPC Class Codes: B29C 64/393 for controlling or regulating additive manufacturing processes
• 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: Y10T 156/17 Surface bonding means and/or assemblymeans with work feeding or handling means
• CPC Class Codes: Y10T 156/1798 with liquid adhesive or adhesive activator applying means

Abstract

A method and apparatus for fabricating a three-dimensional object from porous solid preform layers and at least a pore-filling material. The method includes: (a) providing a work surface parallel to an X-Y plane of a Cartesian coordinate system; (b) feeding a first porous solid preform layer to the work surface; (c) using dispensing devices to dispense a first pore-filling material onto predetermined areas of the first preform layer to at least partially fill in the pores in these areas (hardened areas) for forming the first section of the object; (d) feeding a second porous preform layer onto the first layer, dispensing a second pore-filling material onto predetermined areas of the second layer for forming the second section (the second pore-filling material being the same as or different than the first); (e) repeating the operations from (b) to (d) to stack up and build successive preform layers along the Z-direction for forming multiple layers of the object with the remaining un-hardened areas of individual layers staying as a support structure; (f) sequentially or simultaneously affix successive layers together to form a unitary body; and (g) removing the support structure by exposing the un-hardened areas of the unitary body to a support-collapsing environment, causing the 3-D object to appear.

Claims

1. A method for fabricating a three-dimensional object from individual porous solid preform layers and at least a pore-filling material, said method comprising:

(a) providing a work surface lying substantially parallel to an X-Y plane of an X-Y-Z Cartesian coordinate system defined by three mutually perpendicular X-, Y- and Z-axes;

(b) feeding a first porous solid preform layer to said work surface;

(c) using dispensing means to dispense a first pore-filling material onto predetermined areas of said first porous preform layer to at least partially fill in the pores in said predetermined areas for the purpose of hardening said areas and forming the first section of said 3-D object;

(d) feeding a second porous preform layer onto said first layer, dispensing a second pore-filling material onto predetermined areas of said second layer for hardening said areas and forming the second section of said 3-D object;

(e) repeating the operations from (b) to (d) to stack up and build successive preform layers along the Z-direction of said X-Y-Z coordinate system for forming multiple layers of said object with the remaining un-hardened areas of individual layers staying as a support structure;

(f) providing means to sequentially or simultaneously affix successive layers together to form a unitary body; and

(g) removing said support structure by exposing said un-hardened areas of said unitary body to a support-collapsing environment, causing said 3-D object to appear.

2. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said porous preform layers comprise a water-soluble material composition and said support-collapsing environment comprises water.

3. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said at least one pore-filling material comprises a thermosetting resin which, upon curing, hardens said preform layers.

4. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said at least one pore-filling material comprises a thermoplastic polymer which, upon solidification, hardens said preform layers.

5. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said at least one pore-filling material comprises a polymer-containing solution which, upon solvent removal, hardens said preform layers.

6. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said at least one pore-filling material comprises a chemical composition which reacts with at least one material in said preform layers to form a solid product for hardening said preform layers.

7. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said support structure contains a material composition with a melting point lower than the melting or decomposition temperature of said hardened areas and wherein said support-collapsing environment comprises a higher temperature environment to melt out said low-melting composition for readily collapsing said support structure in said unitary body.

8. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said dispensing means comprise means selected from the group consisting of an inkjet printhead, gear pump, positive displacement pump, air pump, metering pump, extrusion screw, solenoid valve, and thermal sprayer.

9. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said dispensing means comprise multiple nozzles for dispensing a plurality of material compositions.

10. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said feeding of preform layers is accomplished by using a mechanism comprising motor-driven rollers.

11. A method for fabricating a three-dimensional object as set forth in claim 1, wherein said porous solid preform layers comprise a reinforcement composition selected from the group consisting of short fiber, long fiber, whisker, spherical particle, ellipsoidal particle, flake, small platelet, small ribbon, disc, or a combination thereof.

12. A method for fabricating a three-dimensional object as set forth in claim 1, wherein the operation of using dispensing means to dispense a pore-filling material onto predetermined areas of a porous preform layer comprises the steps of:

positioning said dispensing means at a predetermined initial distance from said work surface;

operating and moving said dispensing means relative to said work surface along selected directions in said X-Y plane to dispense and deposit said at least one pore-filling material to said predetermined areas;

moving said dispensing means away from said work surface along said Z-axis direction by a predetermined distance to allow for the feeding and building of a subsequent layer.

13. A method as defined in claim 1, further comprising the steps of:

creating a geometry of said three-dimensional object on a computer with said geometry including a plurality of data points defining the object;

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

moving said dispensing means and said work surface relative to each other in response to said programmed signals.

14. A method as defined in claim 1, further comprising the steps of:

creating a geometry of said three-dimensional object on a computer with said geometry including a plurality of data points defining the object;

each of said data points being coded with a selected material composition;

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

operating said dispensing means in response to said programmed signals to dispense and deposit selected material compositions while said dispensing means and said work surface are moved relative to each other in response to said programmed signals in said predetermined sequence.

15. A method as defined in claim 1, further comprising

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

and

using a computer to determine the thickness and outline of individual layers of said porous solid preform and pore-filling 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.

16. A method as defined in claim 1, further comprising an operation of impregnating said 3-D object with a solidifying liquid material after step (g) in claim 1.

17. A solid freeform fabrication apparatus for making a three-dimensional object from porous solid preform layers, said apparatus comprising:

(a) a work surface to support said object while being built;

(b) a feeder at a predetermined initial distance from said work surface for feeding successive porous solid preform layers onto said work surface one layer at a time;

(c) dispensing means at a predetermined initial distance from said work surface for dispensing at least a pore-filling material onto said porous solid preform layers;

(d) motion devices coupled to said work surface and said dispensing means for moving said dispensing means and said work surface relative to each other in a plane defined by first and second directions and in a third direction orthogonal to said plane to dispense said at least a pore-filling material onto said porous preform layers for forming said 3-D object.

18. Apparatus as set forth in claim 17, wherein said dispensing means comprises a device selected from the group consisting of an ink jet print-head with thermally activated actuator means, an ink jet print-head with piezo-electrically activated actuator means, an air gun with compressed air-powered actuator means, a gear pump, a positive displacement pump, a metering pump, an extrusion screw, a solenoid valve, and a thermal sprayer.

19. Apparatus as set forth in claim 17, further comprising:

a computer-aided design computer and supporting software programs operative to create a three-dimensional geometry of said 3-D object, to convert said geometry into a plurality of data points defining the object, and to generate programmed signals corresponding to each of said data points in a predetermined sequence; and

a three-dimensional motion 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 data points received from said computer.

20. Apparatus as set forth in claim 19, 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 data points 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 data points in a predetermined sequence.

21. Apparatus as set forth in claim 17, further comprising consolidating means coupled to said motion devices for compacting, hardening, or consolidating said preform layers along with said dispensed pore-filling material.

22. Apparatus as set forth in claim 17 wherein said dispensing means comprises a plurality of nozzles each with at least one discharge orifice of a predetermined size for dispensing said at least one pore-filling material.

23. A method for making a three-dimensional object of spatially tailored material compositions, comprising the steps of

creating a geometry of said 3-D object on a computer, said geometry including a plurality of segments defining said object;

each of said segments being coded with a specific material composition;

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

feeding successive layers of porous solid preform onto a work surface upon which said object is built;

providing dispensing means comprising a plurality of nozzles each with at least one discharge orifice of a predetermined size;

operating said dispensing means for dispensing at least two pore-filling materials onto said successive preforms each with a predetermined material distribution pattern according to said program signals;

the un-deposited portion of a layer staying as a portion of a support structure;

during said dispensing step and in response to said programmed signals, moving said dispensing means and said work surface relative to each other 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 pore-filling materials are deposited in successive preform layers as a plurality of segments sequentially formed so that said pore-filling materials in the current layer overly at least a portion of the preceding layer in contact therewith to thereby form an integral unitary body;

removing said support structure by exposing said un-deposited areas of said unitary body to a support-collapsing environment, causing said 3-D object to appear.

24. A method as set forth in claim 23, further comprising additional step of impregnating or coating said 3-D object with a solidifying material to form a protected 3-D composite part.

25. A method as set forth in claim 23, further comprising additional step of providing consolidating means to further sequentially or simultaneously affix successive layers together to form a unitary body.