Three dimensional object fabrication techniques

• US 6,627,835 B1
• Filed: 02/02/2001
• Issued: 09/30/2003
• Est. Priority Date: 02/02/2000
• Status: Expired due to Fees

• Current Assignee: Purdue Research Foundation (Purdue University)
• Original Assignee: Purdue Research Foundation (Purdue University)
• Inventors: Ramani, Karthik, Chung, Chan Woo
• Primary Examiner(s): Evans, Geoffrey S.
• Application Number:
  US09/776,534
• Time in Patent Office: 970 Days
• Field of Search: 700/162, 700/166, 219/121.85, 219/69.17, 219/121.67, 219/121.72
• US Class Current: 219/69.12
• CPC Class Codes: B23H 7/02 Wire-cutting
• CPC Class Codes: B23H 9/00 Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects heat treatment by cathodic discharge C21D1/38
• CPC Class Codes: B23P 15/246 Laminated dies
• CPC Class Codes: B23P 2700/12 Laminated parts
• CPC Class Codes: B29C 33/302 Assembling a large number of mould elements to constitute one cavity
• CPC Class Codes: B29C 64/141 using only solid materials
• 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: B29L 2031/757 Moulds, cores, dies
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

Method and apparatus for making an object. The invention includes the division of a shape of an object into a plurality of layers, and arranging the thickness of the layers based on the curvature of the object to be made. Further, curving edges of the object are replaced with linear sloping edges on the layers. The invention reduces the cost and improves the speed of rapid prototyping, especially with machining methods such as wire electrodischarge machining and laser machining.

Claims

1. A method for making an object, comprising:

preparing a model including a shape of the object;

dividing a first portion of the model into a plurality of layers, each layer including a surface portion corresponding to a portion of the shape of the object, each surface portion of the plurality of layers being a ruled surface;

dividing a second portion of the model into a plurality of primitive objects, each primitive object including a surface portion corresponding to a portion of the shape of the object, each surface portion of the plurality of primitive objects being a ruled surface;

machining each of a first plurality of solid members into a shape corresponding to a different one of the plurality of layers, said machining being one chosen from the group consisting of wire electrodischarge machining and laser machining; and

machining each of a second plurality of solid members into a shape corresponding to a different one of the plurality of primitive objects, said machining being one chosen from the group consisting of wire electrodischarge machining and laser machining.

2. The method of claim 1 wherein the object is a mold.

3. The method of claim 2 wherein each layer includes at least one joining feature, each primitive object includes at least one joining feature, each surface of the joining features having a ruled surface.

4. The method of claim 2 which further comprises molding one or more of the objects with the mold.

5. The method of claim 2 which further comprises assembling the first plurality of solid members and the second plurality of solid members into the mold.

6. The method of claim 1 wherein said plurality of layers includes a first layer of a first thickness and a second layer of a thickness different than the first thickness.

7. The method of claim 6 wherein the first layer has a first constant thickness and the second layer has a second constant thickness.

8. The method of claim 7 wherein the portion of the object includes a variably curving surface, and the thickness of each of the plurality of layers is chosen to correspond to the curvature of the object surface such that thinner layers correspond to portions of the object with greater curvature and thicker layers correspond to portions of the object with lesser curvature.

9. A method for making an object, comprising:

providing a first solid member, a second solid member, and a machining apparatus chosen from the group consisting of wire electrodischarge machining and laser machining;

providing a model of at least a first portion of the object;

dividing the model to have a first layer corresponding to the first solid member and a second layer corresponding to the second solid member, said first layer having a thickness different than the thickness of said second layer, each of said first and second layers including a surface portion corresponding to a portion of the shape of the object, each surface portion of said first and second layers capable of being shaped with the machining apparatus;

shaping the surface portion of the first solid member with the machining apparatus to correspond to the shape of the first layer;

shaping the surface portion of the second solid member with the machining apparatus to correspond to the shape of the second layer;

assembling the first solid member and the second solid member to form at least a part of the object;

providing a primitive object model for a second portion of the object;

shaping a third solid member with the machining apparatus to correspond to the shape of the primitive object model; and

joining said third solid member to said first and second solid members.

10. The method of claim 9 wherein the first portion of the object includes a variably curving surface, and the thinner of the first layer or the second layer includes a surface corresponding to the portion of the object with greater curvature, and the thicker of the first layer or the second layer includes a surface corresponding to the portion of the object with lesser curvature.

11. The method of claim 10 wherein the first and second layers include a surface portion corresponding to a portion of the shape of the object, the surface portion of the first and second layers being a ruled surface.

12. The method of claim 11 wherein each surface of the first and second layers is a ruled surface.

13. The method of claim 9 wherein the object is a mold representing the shape of a second object.

14. The method of claim 13 wherein said model is a computer model.

15. The method of claim 13 wherein said model is a drawing.

16. The method of claim 9 wherein the first layer and the second layer include substantially parallel opposing surfaces.

17. A method for making an object, comprising:

providing a first solid member, a second solid member, and a machining apparatus chosen from the group consisting of wire electrodischarge machining and laser machining;

providing a model of at least a portion of the object;

dividing a portion of the model to have a first layer corresponding to the first solid member and a second layer corresponding to the second solid member, said first layer having a thickness different than the thickness of said second layer, each of said first and second layers including a surface portion corresponding to a portion of the shape of the object, each surface portion of said first and second layers capable of being shaped with the machining apparatus;

shaping the surface portion of the first solid member with the machining apparatus to correspond to the shape of the first layer;

shaping the surface portion of the second solid member with the machining apparatus to correspond to the shape of the second layer;

assembling the first solid member and the second solid member to form at least a part of the object;

dividing a second portion of the model into a plurality of primitive objects, each said primitive object including a surface portion corresponding to a portion of the shape of the object, each surface portion of said primitive objects capable of being shaped with the machining apparatus; and

shaping the surface portion of a plurality of solid members with the machining apparatus to correspond to the shape of said primitive objects.

18. A method for making a mold of an object, comprising:

preparing a model including a shape complementary to the shape of the object;

dividing a first portion of the model into a plurality of layers, each layer including at least one joining feature on each of said layers;

machining each of a plurality of solid members into a shape corresponding to a different one of the plurality of layers, said machining being by a method chosen from the group consisting of wire electrodischarge machining and laser machining; and

assembling the plurality of solid members from two different directions with the joining features into at least a portion of a mold.

19. The method of claim 18 wherein the joining features are of a common configuration.

20. The method of claim 18 which further comprises:

fabricating a joining fixture, the joining fixture including a joining portion adapted and configured to slidingly accept in two non-parallel directions the joining feature of each solid member; and

sliding during said assembling one or more of the machined solid members onto the joining fixture in a first direction and sliding one or more of the machined solid members onto the joining fixture in a second direction not parallel to the first direction.

21. The method of claim 20 wherein each surface of the joining portion is a ruled surface;

and which further comprises machining the joining fixture, said machining being a method chosen from the group consisting of wire electrodischarge machining and laser machining.

22. The method of claim 18 wherein each layer has a thickness different than the thickness of at least one of the other of the plurality of layers.

23. The method of claim 22 wherein each of said plurality of layers are layers of substantially constant thickness.

24. The method of claim 18 wherein each layer includes a surface portion corresponding to a portion of the shape of the object, each surface portion of the plurality of layers being a ruled surface.

25. A method for making an object, comprising:

creating a computer model of the object with a CAD program;

slicing a first portion of the model in a first direction to create a first plurality of layers;

slicing a second portion of the model in a different direction to create a second plurality of layers;

machining a first plurality of solid members into shapes respectively corresponding to the shapes of said layers in said first plurality of layers;

machining a second plurality of solid members into shapes respectively corresponding to the shapes of said layers in said second plurality of layers; and

assembling said first and second pluralities of solid members in first and second non-parallel directions, respectively.

26. The method of claim 25, wherein said machining is performed with a wire electrodischarge machine.

27. The method of claim 26, wherein said first and second portions of the model are sliced in directions which are substantially perpendicular to each other, and wherein said first and second directions of assembly are substantially perpendicular to each other.