Method of making a three-dimensional object by stereolithography

• US 6,264,873 B1
• Filed: 09/24/1999
• Issued: 07/24/2001
• Est. Priority Date: 04/18/1988
• Status: Expired due to Fees

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Inventors: Richter, Jan, Hguyen, Hop D., Smalley, Dennis R., Hull, Charles W., Leyden, Richard N., Manners, Chris R., Pang, Thomas H., Jacobs, Paul F., Allen, Kerry J., Gigl, John J.
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US09/401,769
• Time in Patent Office: 669 Days
• Field of Search: 264/401, 700/120
• 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: B29C 64/40 Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• CPC Class Codes: B29C 67/02 Moulding by agglomerating B29C67/20 takes precedence
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B44B 1/006 using computer control means
• CPC Class Codes: G01J 1/4257 applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam monitoring arrangements for lasers in general H01S3/0014
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• CPC Class Codes: G03F 7/70416 2.5D lithography
• CPC Class Codes: G05B 2219/49013 Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 17/10 Constructive solid geometry [CSG] using solid primitives, e.g. cylinders, cubes
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation

Abstract

An improved method for stereolithographically making an object by alternating the order in which similar sets of vectors are exposed over two or more layers. In another method, a pattern of tightly packed hexagonal tiles are drawn. Each tile is isolated from its neighboring tiles by specifying breaks of unexposed material between the tiles. Using an interrupted scan method, vectors are drawn with periodic breaks along their lengths. In another method, modulator and scanning techniques are used to reduce exposure problems associated with the acceleration and deceleration of the scanning system when jumping between vectors or changing scanning directions. In another method, a capability for automatically inserting vents an drains into a three-dimensional object representation is provided.

Claims

1. An improved method for constructing a three-dimensional object from a medium solidifiable upon exposure to prescribed stimulation, comprising forming successive layers of the medium applied to previously formed layers of the medium, and selectively exposing the layers to prescribed stimulation in patterns to construct the three-dimensional object cross-section by cross-section, the improvement comprising:

forming at least a first portion of a first cross-section with a first pattern comprising a plurality of lines of exposure;

forming at least a second portion of a second cross-section with a second pattern comprising a plurality of lines of exposure, the second pattern being different from the first pattern.

2. The method of claim 1 wherein at least a portion of at least the first cross-section is formed with at least a first boundary and a second boundary wherein the first boundary is offset to an interior portion of the second boundary.

3. The method of claim 2 wherein the second boundary is formed after formation of the first boundary.

5. The method of claim 1 wherein the first cross-section and the second cross-section are different and the first and second portions comprise internal portions of the object being constructed.

6. The method of claim 5 wherein at least some of the lines of exposure of the first pattern result in solidified regions of medium, spaced, at least in part, from one another by gaps.

7. The method of claim 6 wherein at least some of the solidified regions are separated by gaps of at least about 0.1 inch.

8. The method of claim 6, wherein unsolidified medium is located in the gaps during construction of the object and wherein after object construction, unsolidified medium located in the gaps is at least partially removed.

9. The method of claim 5 wherein the second pattern is different from the first pattern, at least in part, in that at least some of the lines of exposure of the second pattern are offset from at least some of the lines of exposure of the first pattern.

10. The method of claim 9 wherein at least some of the lines of exposure of the first pattern result in solidified regions of medium, spaced, at least in part, from one another by gaps.

11. The method of claim 5 wherein at least some lines of exposure of the first pattern result in breaks in the solidified medium along a length of the lines.

12. The method of claim 11 wherein the first pattern is different from the second pattern, at least in part, as a result of the lines of exposure of the first pattern resulting in breaks in different locations than any breaks produced as a result of the lines of exposure of the second pattern.

13. The method of claim 12 wherein the first pattern is further differentiated from the second pattern, at least in part, in that the first pattern includes at least some lines of exposure offset from at least some of the lines of exposure of the second pattern.

14. The method of claim 12 wherein the breaks are wide enough to allow unsolidified medium to flow through the breaks.

15. The method of claim 5 wherein at least some of the lines of the first pattern expose the medium in a tighter configuration near a boundary of the first cross-section and a looser configuration further away from the boundary of the first cross-section.

16. The method of claim 15 wherein at least some of the lines of exposure of the first pattern result in solidified regions of medium, spaced, at least in part, from one another by gaps.

17. The method of claim 15 wherein the second pattern is different from the first pattern, at least in part, in that at least some of the lines of exposure of the second pattern are offset from at least some of the lines of exposure of the first pattern.

18. The method of claim 15 wherein at least some lines of exposure of the first pattern result in breaks in the solidified medium along a length of the lines.

19. The method of claim 18 wherein the first pattern is different from the second pattern, at least in part, as a result of the lines of exposure of the first pattern resulting in breaks in different locations than any breaks produced as a result of the lines of exposure of the second pattern.

20. The method of claim 19 wherein the breaks are wide enough to allow unsolidified medium to flow through the breaks.

21. The method of claim 5 wherein at least some of the lines of the first pattern expose the medium in a looser configuration near a boundary of the first cross-section and a tighter configuration further away from the boundary of the first cross-section.

22. The method of claim 21 wherein at least some of the lines of exposure of the first pattern result in solidified regions of medium, spaced, at least in parts, from one another by gaps.

23. The method of claim 21 wherein at least some lines of exposure of the first pattern result in breaks in the solidified medium along a length of the lines.

24. The method of claim 5 wherein at least a portion of at least the first cross-section is formed with at least a first boundary and a second boundary wherein the first boundary is offset to an interior portion of the second boundary.

25. The method of claim 24 wherein at least some of the lines of exposure of the first pattern result in solidified regions of medium, spaced, at least in part, from one another by gaps.

26. The method of claim 25 wherein at least some of the lines of exposure of the second pattern result in solidified regions of medium, spaced, at least in part, from one another by gaps.

27. The method of claim 26 wherein at least some lines of exposure of the first pattern result in breaks in the solidified medium along a length of the lines.

28. The method of claim 24 wherein the second boundary is formed after formation of the first boundary.

4. An improved method for constructing a three-dimensional object from a medium solidifiable upon exposure to prescribed stimulation, comprising the successive formation of layers of the medium applied to previously formed layers of the medium, each layer of the medium having a desired thickness, and selectively exposing the layers to prescribed stimulation in patterns, to construct the three-dimensional object cross-section by cross-section, the patterns including lines of exposure, with the exposure resulting in a cure depth and a cure width, the improvement comprising:

forming at least a portion of a first cross-section with a first set of lines of exposure which yield a cure depth that is less than the layer thickness; and

forming at least the portion of the first cross-section with a second set of lines of exposure which, in combination with the exposure of the first set, provides a sufficient quantity of exposure to achieve adhesion to a previously solidified cross-section.

29. The method of claim 4 wherein the first set of lines of exposure result in solidified medium having a contiguous width greater than a width of an individual line exposure.

30. The method of claim 29 wherein at least some of the lines of exposure of the second set are not parallel to and intersect at least some of the lines of exposure of the first set.

31. A method of constructing a three-dimensional object from a solidifiable medium, comprising:

supplying data descriptive of the object,

forming layers of unsolidified medium adjacent to previously formed cross-sections of the object in preparation for forming subsequent cross-sections of the object;

selectively exposing the layers of unsolidified medium to prescribed stimulation to selectively solidify portions of the layers to form successive cross-sections of the object;

adhering the cross-sections together upon formation to construct the three-dimensional object cross-section by cross-section, the object comprising object regions and non-object regions separated by surfaces of the object;

leaving at least a portion of the surface of the object unsolidified to form a passage from the object region to the non-object region so as to allow at least a portion of any unsolidified medium within the object region to be at least partially removed through the passage.

32. The method of claim 31 wherein the object region comprises walls of the object.

33. The method of claim 31 wherein the at least portion of the surface of the object left unsolidified comprises horizontal sections of the object.

34. The method of claim 31 wherein the medium is a liquid photopolymer.