Method and apparatus for identifying surface features associated with selected lamina of a three-dimensional object being stereolithographically formed

• US 5,945,058 A
• Filed: 05/13/1997
• Issued: 08/31/1999
• Est. Priority Date: 05/13/1997
• 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., Manners, Chris R.
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US08/854,950
• Time in Patent Office: 840 Days
• Field of Search: 264/40.1, 264/308, 264/401, 425/135, 425/174.4, 364/468.27, 364/130
• 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 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29K 2995/0073 smooth
• 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 50/00 Data acquisition or data processing for additive manufacturing

Abstract

This invention relates to the stepwise layer-by-layer formation of a three-dimensional object through application of the principles of stereolithography and to the automatic detection of surface features of each layer of a three-dimensional object to manufacture parts more reliably, more accurately and more quickly. Automatic detection of trapped volume regions and size of solidified cross-sectional regions are disclosed. Automatic selection of recoating styles is made based on (1) the detected regions,(2) empirically or otherwise determined optimum recoating styles for different types of regions, and (3) a look-up table, other correlation system, or processor for associating recoating style information with laminae containing particular identified regions.

Claims

1. A method of producing a three-dimensional object from a plurality of adhered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

supply data representing the object to be formed;

forming a layer of material over any previously formed adjacent lamina;

selectively exposing the layer of the material to prescribed stimulation in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

repeating forming the layer and exposing the layer a plurality of times to form the three-dimensional object;

automated processing of the data to identify which laminae are identified with a desired geometric feature; and

wherein forming, for at least some layers, comprises utilization of a first recoating style when the adjacent lamina includes the desired geometric feature and comprises utilization of a second recoating style when the adjacent lamina does not include the desired geometric feature.

2. The method of claim 1 wherein the selective physical transformation is the conversion of the material from a flowable state to a solid state.

3. The method of claim 2 wherein the desired geometric feature is a trapped volume.

4. The method of claim 3 wherein the desired geometric feature is a trapped volume having a linear dimension or area larger than a predetermined amount.

5. The method of claim 3 wherein the trapped volume associated with a given lamina comprises an actual trapped volume which is the result of a closed loop of solidified material completely surrounding a region of unsolidified material, which region of unsolidified material is effectively bounded from below by at least one of 1) solidified material on the adjacent lamina, or 2) a region identified as a trapped volume on the previously formed adjacent lamina.

6. The method of claim 5 wherein the effective bounding from below is determined by setting a lower limit on the minimum percentage of the region of unsolidified material which is bounded from below by a combination of one or both of 1) solidified material on the adjacent lamina, 2) a region identified as a trapped volume on the previously formed adjacent lamina.

7. The method of claim 3 wherein the trapped volume associated with a given lamina comprises an effective trapped volume which results, at least in part, from one or more horizontal breaches in a boundary wall that otherwise would surround a region of unsolidified material, which breaches are each less than a specified amount, and which region of unsolidified material is effectively bounded from below by at least one of 1) solidified material on the adjacent lamina, 2) a region identified as a trapped volume on the previously formed adjacent lamina.

8. The method of claim 3 wherein the trapped volume associated with a given lamina comprises an effective trapped volume which results, at least in part, from the given lamina being vertically located less than M laminae above a lamina containing an identified trapped volume region.

9. The method of claim 3 wherein processing data further comprises identifying horizontal extents of any trapped volumes associated with a given lamina.

10. The method of claim 1 wherein forming a layer includes the utilization of a recoating device that sweeps at or above the desired working surface and wherein the first recoating style differs from the second recoating style by at least the specification of a different sweeping speed for the recoating device.

11. The method of claim 1 wherein forming a layer includes the utilization of a material dispensing device.

15. A method of producing a three-dimensional object as claimed in claim 1, wherein the desired geometric feature includes a trapped volume and wherein the processing of the data comprises:

deriving a potential trapped volume region associated with lamina N including unioning any up-facing regions associated with lamina N-1 and any trapped volume regions associated with lamina N-1;

identifying the individual holes associated with lamina N;

comparing the individual holes associated with lamina N to the potential trapped volume region associated with lamina N; and

identifying a trapped volume as being associated with lamina N if at least one individual hole for lamina N has an overlap with the potential trapped volume region associated with lamina N which is greater than a predetermined criteria.

23. The method of claim 1, wherein the processing of the data is performed by a computer.

24. The method of claim 1, wherein the processing of the data includes utilization of comparison operators between at least two laminae.

25. The method of claim 1, wherein the processing of the data includes the utilization of Boolean comparison operators between at least two laminae.

26. The method of claim 1, wherein the forming, for at least some layers, comprises utilization of an automatic specification of coating parameters.

12. An apparatus for producing a three-dimensional object from a plurality of adhered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

a memory to store data representing the object to be formed;

a coating device to form a layer of material over any previously formed adjacent lamina;

a source of prescribed stimulation;

a scanner to selectively direct the prescribed stimulation onto the layer of the material in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

a processor to provide automated processing of the data to identify which laminae are identified with a desired geometric feature; and

wherein the coating device includes at least one adjustable parameter and wherein the at least one adjustable parameter is set to a first value when the adjacent lamina includes the desired geometric feature and is set to a second value, which is different from the first value when the adjacent lamina does not include the desired geometric feature.

16. An apparatus for producing three-dimensional data as claimed in claim 12, wherein the desire geometric feature includes a trapped volume and wherein the processor is programmed to:

(a) derive a potential trapped volume region associated with lamina N including unioning any up-facing regions associated with lamina N-1 and any trapped volume regions associated with lamina N-1;

(b) identify individual holes associated with lamina N;

(c) compare the individual holes associated with lamina N to the potential trapped volume region associated with lamina N; and

(d) identify a trapped volume as being associated with lamina N if at least one individual hole for lamina N has an overlap with the potential trapped volume region associated with lamina N which is greater than a predetermined criteria.

27. The apparatus of claim 12, wherein the processor includes a computer.

28. The apparatus of claim 12, wherein the processor is programmed to automatically specify coating parameters.

13. A method of producing a three-dimensional object from a plurality of adhered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

supplying data representing the object to be formed;

forming a layer of material over any previously formed adjacent lamina;

selectively exposing the layer of the material to prescribed stimulation in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

repeating forming a layer and exposing the layer a plurality of times to form the three-dimensional object; and

automated processing of the data to identify which laminae include a trapped volume,

wherein forming, for at least some layers, comprises utilization of a first recoating style when the adjacent lamina has an associated trapped volume and comprises utilization of a second recoating style when the adjacent lamina does not include a trapped volume.

18. A method for forming a three-dimensional object as claimed in claim 13, wherein the processing of the data comprises:

deriving a potential trapped volume region associated with lamina N including unioning any up-facing regions associated with lamina N-1 and any trapped volume regions associated with lamina N-1;

identifying individual holes associated with lamina N;

comparing the individual holes associated with lamina N to the potential trapped volume region associated with lamina N; and

identifying a trapped volume as being associated with lamina N if at least one individual hole for lamina N has an overlap with the potential trapped volume region associated with lamina N which is greater than a predetermined criteria.

29. The method of claim 13, wherein the processing of the data is performed by a computer.

30. The method of claim 13 wherein the processing of the data includes utilization of comparison operators between at least two laminae.

31. The method of claim 13, wherein the processing of the data includes the utilization of Boolean comparison operators between at least two laminae.

32. The method of claim 13, wherein the forming, for at least some layers, comprises utilization of an automatic specification of coating parameters.

14. An apparatus for producing a three-dimensional object from a plurality of adhered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

a memory to store data representing the object to be formed;

a coating device to form a layer of material over any previously formed adjacent lamina;

a source of prescribed stimulation;

a scanner to selectively direct the prescribed stimulation onto the layer of the material in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

a processor to provide automated processing of the data to identify which laminae are identified with a trapped volume feature; and

wherein the coating device includes at least one adjustable parameter and wherein the at least one adjustable parameter is set to a first value when the adjacent lamina includes the trapped volume feature and is set to a second value, which is different from the first value when the adjacent lamina does not include the trapped volume feature.

17. An apparatus for producing three-dimensional data as claimed in claim 14, wherein the processor is programmed to:

(a) derive a potential trapped volume region associated with lamina N including unioning any up-facing regions associated with lamina N-1 and any trapped volume regions associated with lamina N-1;

(b) identify individual holes associated with lamina N;

(c) compare the individual holes associated with lamina N to the potential trapped volume region associated with lamina N; and

(d) identify a trapped volume as being associated with lamina N if at least one individual hole for lamina N has an overlap with the potential trapped volume region associated with lamina N which is greater than a predetermined criteria.

33. The apparatus of claim 14, wherein the processor includes a computer.

34. The apparatus of claim 14, wherein the processor is programmed to automatically specify coating parameters.

19. A method of producing a three-dimensional object from a plurality of adhered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

supplying data representing the object to be formed;

forming a layer of material over any previously formed adjacent lamina;

selectively exposing the layer of the material to prescribed stimulation in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

repeating forming the layer and exposing the layer a plurality of times to form the three-dimensional object; and

processing the data to identify which laminae are identified with a desired geometric feature comprising a trapped volume region;

wherein forming, for at least some layers, comprises utilization of a first recoating style when the adjacent lamina includes the desired geometric feature and comprises utilization of a second recoating style when the adjacent lamina does not include the desired geometric feature; and

wherein the processing of the data comprises;

deriving the potential trapped volume region associated with lamina N including unioning any up-facing regions associated with lamina N-1 and any trapped volume regions associated with lamina N-1;

identifying individual holes associated with lamina N;

comparing the individual holes associated with lamina N to the potential trapped volume region associated with lamina N; and

identifying a trapped volume as being associated with lamina N if at least one individual hole for lamina N has an overlap with the potential trapped volume region associated with lamina N which is greater than a predetermined criteria.

20. An apparatus for producing a three-dimensional object from a plurality of adhered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

a memory for storing data representing the object to be formed;

a coating device for forming a layer of material over any previously formed adjacent lamina;

a source of prescribed stimulation;

a scanner for selectively directing the prescribed stimulation onto the layer of the material in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

a processor for processing the data to identify which laminae are identified with a desired geometric feature comprising a trapped volume region; and

wherein the coating device includes at least one adjustable parameter and wherein the at least one adjustable parameter is set to a first value when the adjacent lamina includes the desired geometric feature and is set to a second value, which is different from the first value when the adjacent lamina does not include the desired geometric feature;

wherein the processor is programmed to;

(1) derive the potential trapped volume region associated with lamina N including unioning any up-facing regions associated with lamina N-1 and any trapped volume regions associated with lamina N-1;

(2) identify individual holes associated with lamina N;

(3) compare the individual holes associated with lamina N to the potential trapped volume region associated with lamina N; and

(4) identify a trapped volume as being associated with lamina N if at least one individual hole for lamina N has an overlap with the potential trapped volume region associated with lamina N which is greater than a predetermined criteria.

21. An apparatus for producing a three-dimensional object from a plurality of adhered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

means for storing data representing the object to be formed;

means for forming a layer of material over any previously formed adjacent lamina;

means for supplying prescribed stimulation;

means for selectively directing the prescribed stimulation onto the layer of the material in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

means for providing automated processing of the data to identify which laminae are identified with a desired geometric feature; and

wherein the means for forming includes at least one adjustable parameter and wherein the at least one adjustable parameter is set to a first value when the adjacent lamina includes the desired geometric feature and is set to a second value, which is different from the first value when the adjacent lamina does not include the desired geometric feature.

22. An apparatus for producing a three-dimensional object from a plurality of adjered laminae formed from a material capable of selective physical transformation upon exposure to prescribed stimulation, comprising:

means for storing data representing the object to be formed;

means for forming a layer of material over any previously formed adjacent lamina,

means for supplying prescribed stimulation;

means for selectively directing the prescribed stimulation onto the layer of the material in accordance with the data to form a next lamina of the object and to adhere said next lamina to any previously formed adjacent lamina;

means for providing automated processing of the data to identify which laminae are identified with a trapped volume feature; and

wherein the means for forming includes at least one adjustable parameter and wherein the at least one adjustable parameter is set to a first value when the adjacent lamina includes the trapped volume feature and is set to a second value, which is different from the first value when the adjacent lamina does not include the trapped volume feature.