Laminated object manufacturing apparatus and method

• US 5,876,550 A
• Filed: 02/21/1997
• Issued: 03/02/1999
• Est. Priority Date: 10/05/1988
• Status: Expired due to Term

• Current Assignee: Cubic Technologies, Inc.
• Original Assignee: Helisys, Inc.
• Inventors: Pak, Sung Sik, Feygin, Michael
• Primary Examiner(s): SELLS, JAMES D
• Application Number:
  US08/793,388
• Time in Patent Office: 739 Days
• Field of Search: 156/64, 156/250, 156/256, 156/264, 156/267, 156/272.2, 156/272.8, 156/275.5, 156/379.6, 156/379.8, 156/379.9, 156/380.9, 156/510, 156/512, 156/538, 264/405, 264/308, 264/DIG. 59, 425/174.4
• US Class Current: 156/264
• CPC Class Codes: A61F 2002/30952 using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: B22C 9/00 Moulds or cores uniquely adapted to particular casting processes B22D; Moulding processes
• CPC Class Codes: B22F 10/20 Direct sintering or melting
• CPC Class Codes: B22F 10/32 of the atmosphere, e.g. composition or pressure in a building chamber
• CPC Class Codes: B22F 10/366 Scanning parameters, e.g. hatch distance or scanning strategy
• CPC Class Codes: B22F 10/47 characterised by structural features
• CPC Class Codes: B22F 10/64 by thermal means control of energy beam parameters for post heating B22F10/364
• CPC Class Codes: B22F 12/41 characterised by the type, e.g. laser or electron beam
• CPC Class Codes: B22F 12/63 Rollers
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• CPC Class Codes: B22F 3/004 Filling molds with powder feeding material to presses in general B30B15/302
• CPC Class Codes: B29C 41/36 Feeding the material on to the mould, core or other substrate
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 64/188 involving additional operations performed on the added layers, e.g. smoothing, grinding or thickness control surface shaping B29C59/00; after-treatment of articles without altering their shape B29C71/00
• CPC Class Codes: B29C 64/364 Conditioning of environment
• 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: B32B 2038/1891 Using a robot for handling the layers
• CPC Class Codes: B32B 2309/70 : Automated, e.g. using a computer or microcomputer
• CPC Class Codes: B32B 37/0076 : characterised in that the layers are not bonded on the totality of their surfaces
• CPC Class Codes: B32B 38/1841 : during laying up
• 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: G05B 19/4099 : Surface or curve machining, making 3D objects, e.g. desktop manufacturing
• CPC Class Codes: G05B 19/41 : characterised by interpolation, e.g. the computation of intermediate points between programmed end points to define the path to be followed and the rate of travel along that path G05B19/25, G05B19/31, G05B19/37, G05B19/39, G05B19/40 take precedence
• CPC Class Codes: G05B 2219/36199 : Laser cutting
• CPC Class Codes: G05B 2219/45036 : Waterjet cutting
• CPC Class Codes: G05B 2219/49011 : Machine 2-D slices, build 3-D model, laminated object manufacturing LOM
• CPC Class Codes: G05B 2219/49016 : Desktop manufacturing [DTM]; Solid freeform machining [SFM]; Solid freeform fabrication [SFF]
• CPC Class Codes: G05B 2219/49018 : Laser sintering of powder in layers, selective laser sintering SLS
• CPC Class Codes: G05B 2219/49021 : Deposit layer, machine, mill layer, then new layer, SDM solid deposit manufacting
• CPC Class Codes: G05B 2219/49032 : Bond layers with glue, solder, welding, brazing in LOM
• CPC Class Codes: Y02P 10/25 : Process efficiency
• CPC Class Codes: Y10T 156/1062 : Prior to assembly
• CPC Class Codes: Y10T 156/1075 : of plural laminae from single stock and assembling to each other or to additional lamina
• CPC Class Codes: Y10T 156/108 : Flash, trim or excess removal
• CPC Class Codes: Y10T 156/13 : Severing followed by associating with part from same source
• CPC Class Codes: Y10T 156/17 : Surface bonding means and/or assemblymeans with work feeding or handling means

Abstract

The present invention generally relates to manufacturing apparatus, method of manufacture, and products manufactured thereby and more particularly to an integral three-dimensional object (6, 15) formed from individually contoured laminations (4, 62) of the same or gradually varying shape, successive laminae of that object being produced out of thin sheet or powder based materials (1, 60) through the cutting, fusing or physicochemical property changing action generated by a computer directed beam (7) of concentrated energy or matter, successive substantially planar laminations (4, 62) of that object (6, 15) being automatically stacked together for step-wise laminar buildup of the desired object (6, 15).

Claims

1. A method of converting layers of sheet material into a plurality of slices that form a three-dimensional object, said method comprising the steps of:

defining wanted and unwanted regions in each layer of said sheet material, the wanted regions comprising the slices of said three dimensional object;

forming a stack of said sheet material by (a) positioning each said layer of said sheet material over a work station and (b) strongly bonding each of said wanted regions to at least one adjacent wanted region of said sheet material using a forming tool movably mounted over said work station, without strongly bonding unwanted regions of sheet material to adjacent unwanted regions, whereby removal of said unwanted regions is facilitated;

forming a boundary line between wanted and unwanted regions of each of said layers by cutting said sheet material with said forming tool; and

forming a plurality of lines in unwanted regions of at least some of said layers by cutting said sheet material with said forming tool to further facilitate removal of said unwanted regions.

2. The method of claim 1, wherein said forming tool is a laser and said step of strongly bonding is performed by utilizing said forming tool to apply defocussed energy to said wanted regions.

3. The method of claim 2, wherein said step of forming a line is performed by utilizing said laser to apply focussed energy.

4. The method of claim 2, wherein the lines formed in said unwanted portions are closer together near the boundary line than the lines farther from the boundary line.

5. The method of claim 4, wherein said step of forming said lines in said unwanted regions comprises forming a cross-hatched pattern in said unwanted regions with at least some of said lines intersecting.

6. The method of claim 5, wherein said step of defining regions comprises defining an unwanted region interior to the wanted region, said method further comprising:

removing said interior unwanted portion prior to positioning a subsequent layer of said sheet material over the work station.

7. The method of claim 2, wherein said sheet material includes adhesive on a side facing said stack and the method further comprises the step of:

weakly bonding said unwanted regions to said stack by utilizing a roller which moves relative to said work station and applies force to bond adjacent layers of material to each other, said step of weakly bonding being performed prior to said step of strongly bonding.

8. The method of claim 7, further comprising the step of:

heating only said unwanted portions of said layer sufficiently to weaken the bonds between the unwanted portions and an adjacent layer in said stack to facilitate removal of said unwanted portions after said three-dimensional object is formed.

9. The method of claim 8, wherein said step of forming said lines in said unwanted portions comprises forming a cross-hatched pattern in said unwanted portions with said forming tool so that at least some of said lines intersect other lines in said unwanted portions to facilitate removal of said unwanted portions after said stack is formed.

10. The method of claim 2, wherein said forming tool is a laser and further comprising the step of:

burning at least some of said unwanted portions with said laser to form an indentation and prevent unwanted portions in subsequent layers from bonding to said stack.

11. The method of claim 2, further comprising the steps of:

sensing a stack height of said work station;

determining an average layer height by utilizing the height of the stack and the number of layers previously placed on said stack and predicting the height of the stack with the next layer; and

defining said wanted and unwanted regions in said layer using information regarding the predicted height of the next layer.

12. A laminated object manufacturing system for forming sheet material into a three-dimensional object comprised of a stack of slices of the sheet material, comprising:

a handling mechanism for supplying incremental layers of said sheet material and positioning each said layer over a work station on which a plurality of said layers have been previously positioned and portions bonded together to form a stack, the system characterized by;

a controller defining wanted and unwanted regions in a layer of said sheet material, the wanted regions comprising a slice in said layer;

a forming tool mounted to move in response to signals from the controller relative to said work stage, said controller driving said forming tool to strongly bond said wanted regions of said layer of sheet material comprising said slice to said stack without strongly bonding unwanted regions of said layer not comprising part of said slice to said stack to facilitate removal of said unwanted regions, said controller also driving said forming tool to form a line at a boundary between wanted and unwanted regions, and forming a pattern of lines in said unwanted portions to facilitate removal of said unwanted portions after said stack is formed.

13. The system of claim 12, further comprising:

a sensor mounted to sense the height of said stack on said work station, wherein said controller receives input from said sensor to predict the height of the next layer, and defines wanted and unwanted regions in said layer using information regarding the predicted height of the next layer.

14. The system of claim 12, wherein said handling mechanism comprises a supply roller and a receiving roller disposed on opposite sides of said work station adapted to deliver said sheet across said work station.

15. The system of claim 12, wherein said forming tool is a laser mounted above said work station to apply defocussed energy to strongly bond said wanted regions to each other, and to apply focussed energy to cut said material along said lines.

16. The system of claim 12, wherein said sheet material is pre-coated with adhesive, said system including a bonding tool mounted to move relative to said work station to apply force and bond adjacent layers of material to each other.

17. The system of claim 12, wherein said controller defines an inner edge of said slice surrounding an interior unwanted portion, defines an outer edge of said slice surrounded by an exterior unwanted portion, and drives said forming tool to form said pattern in only said exterior unwanted portion, said system further including a device for removing said interior unwanted portion prior to positioning a subsequent layer of said sheet material over the work station.

18. A method of converting layers of sheet material into a plurality of slices that form a three-dimensional object, including forming a stack of layers of said sheet material by positioning each layer of said sheet material over a work station and bonding each layer to a layer below, said method characterized by the steps of:

sensing a stack height on said work station before positioning one of said layers;

determining an average layer height based on said sensed stack height and a number of layers previously placed on said stack;

adding said sensed stack height and said average layer height to obtain a new stack height;

positioning said one layer of said sheet material over said stack and bonding said one layer to said stack;

calculating wanted and unwanted regions in said one layer using said new stack height and information regarding the shape of said three-dimensional object, said wanted regions comprising the slices of said three dimensional object; and

forming said wanted and unwanted regions in said one layer.

19. A laminated object manufacturing system for converting layers of sheet material into a plurality of slices that form a three-dimensional object, including a handling mechanism for supplying incremental layers of said sheet material and forming a stack of layers of said sheet material by positioning each layer over a work station and bonding each layer to a layer below, characterized by:

a sensing means for sensing a stack height on said work station before positioning one of said layers;

means for transmitting said sensed stack height;

a controller for determining an average layer height based on said sensed stack height and the number of layers previously placed on said stack, wherein said handling mechanism positions said one layer of said sheet material over said stack and bonds said one layer to said stack, and said controller adds said sensed stack height and said average layer height to obtain a new stack height, and calculates wanted and unwanted regions in said one layer using said new stack height and information regarding the shape of said three-dimensional object, said wanted regions comprising the slices of said three dimensional object; and

a forming tool mounted to move relative to said work station in response to signals from said controller to form said wanted and unwanted regions in said one layer.

20. A method of converting layers of sheet material into a plurality of slices that form a three-dimensional object, including forming a stack of layers of said sheet material by positioning each layer of said sheet material over a work station and bonding each layer to a layer below, said method characterized by the steps of:

forming a wanted region and an unwanted region in one of said layers using a forming tool movably mounted over the work station, said wanted region comprising one slice of said three dimensional object; and

forming cross-hatching in said unwanted region of said one layer with said forming tool to facilitate removal of said unwanted region after forming said three-dimensional object, said cross-hatching in said unwanted region closer to the edges of said slice being more dense than the cross-hatching farther from the edges of said slice.

21. The method of claim 20, further including the steps of:

positioning a second layer of said sheet material on said stack and bonding said second layer to said one layer;

forming a wanted region and an unwanted region in said second layer;

positioning a third layer of said sheet material on said stack and bonding said third layer to said second layer without cross-hatching said second layer; and

forming a wanted region and an unwanted region in said third layer.

22. The method of claim 21, further including simultaneously cross-hatching the unwanted regions of said second layer and said third layer.

23. An apparatus for forming a three-dimensional object from a plurality of shaped laminations, comprising:

a platform on which a plurality of shaped laminations can be placed together to form a stack;

means for bonding successively placed shaped laminations by heating at least portions of an upper lamination in the stack to a first temperature;

an enclosure surrounding the stack, wherein the enclosure maintains the stack at a second temperature elevated above ambient but below the first temperature during formation of the object; and

a source of heat thermally coupled to the enclosure.

24. The apparatus of claim 23, wherein the enclosure surrounds the stack and the bonding means.

25. The apparatus of claim 24, further including a source of heat within the enclosure for maintaining the interior of the enclosure at an elevated temperature.

26. The apparatus of claim 25, wherein the heat source is an infrared lamp.

27. The apparatus of claim 25, wherein the heat source is a convection heater.

28. The apparatus of claim 25, wherein the heat source is an ultraviolet lamp.

29. The apparatus of claim 25, wherein the heat source is a heating element within the platform.

30. The apparatus of claim 24, further including a heated jacket surrounding the stack.

31. The apparatus of claim 23, wherein the enclosure comprises a heated jacket surrounding the stack.

32. The apparatus of claim 31, wherein the apparatus includes a support cylinder surrounding the stack with the heated jacket surrounding the support cylinder, the platform being adapted for vertical movement with the support cylinder.

33. The apparatus of claim 23, further including, within the enclosure:

a roll for supplying sheet material to the platform; and

a refrigeration unit surrounding the roll.

34. The apparatus of claim 23, further including:

an oven into which the stack can be placed after forming the three-dimensional object so that the temperature of the stack can be reduced to ambient at a rate sufficient to avoid warpage.

35. The apparatus of claim 23, wherein the bonding means is a laser.

36. The apparatus of claim 23, wherein the bonding means is a heated roller.

37. The apparatus of claim 23, wherein the bonding means is an ultraviolet lamp.

38. A method of forming a three-dimensional object from a plurality of shaped laminations, comprising the steps of:

supplying layers of material to form a stack;

monitoring the number of layers supplied to the stack;

sensing a first height of the stack;

determining a computational layer thickness using the sensed first height and information regarding a number of layers previously supplied to the stack;

predicting a second height of the stack based on the first height and the computational layer thickness;

supplying data regarding the shaped laminations for the three dimensional object at different heights; and

forming a shaped lamination in a layer of material from data corresponding to the second stack height.

39. The method of claim 38, wherein the step of forming includes shaping a top layer on the stack.

40. The method of claim 39, wherein the material is powder and the shaping includes melting portions of the layer within the shaped lamination to bond the top layer to shaped laminations previously bonded to the stack.

41. The method of claim 40, wherein the material is sheet and the step of forming includes cutting the shaped lamination in a top sheet.

42. The method of claim 41, further including bonding the shaped lamination cut in the top sheet to shaped laminations previously bonded to the stack.

43. The method of claim 38, wherein the step of determining comprises dividing the total stack height by the total number of layers supplied to the stack.

44. The method of claim 38, wherein the step of forming includes shaping the lamination off the stack before supplying it to the stack.

45. The method of claim 38, wherein the material is sheet and the step of supplying includes bonding each sheet to the stack with a bonding tool adapted to apply compression to the stack.

46. The method of claim 45, wherein the step of sensing includes sensing a force between the bonding tool and the stack and determining the first stack height from the force.