Solid imaging apparatus and method with coating station

• US 5,626,919 A
• Filed: 05/18/1992
• Issued: 05/06/1997
• Est. Priority Date: 03/01/1990
• Status: Expired due to Term

• Current Assignee: DSM Desotech Incorporated (DSM-Firmenich AG)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Clausen, Christian H., Mickish, Daniel J., Vassiliou, Eustathios, Chapman, Brian G.
• Primary Examiner(s): PADGETT, MARIANNE L
• Application Number:
  US07/884,030
• Time in Patent Office: 1,814 Days
• Field of Search: 427/53.1, 427/54.1, 427/45.1, 427/430.1, 427/510, 427/512, 427/498, 427/581, 118/620, 118/50.1, 118/413, 118/423, 118/428, 118/429, 430/298, 430/306, 430/324, 264/1.4, 264/22, 264/24, 264/25, 264/26, 264/401, 264/405, 264/494, 264/496, 425/6, 425/86, 425/174, 425/174.1, 425/174.4
• US Class Current: 427/510
• 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 70/00 Materials specially adapted for additive manufacturing

Abstract

A solid imaging apparatus and method produces an integral three-dimensional object from a multiplicity of cross sectional portions of the object by selectively exposing successive layers of a liquid photoformable composition to actinic radiation. The apparatus includes a vessel for containing the composition so as to present a free surface, and a movable platform disposed within the vessel below the free surface. Part of the composition is transferred above the free surface by lowering and raising a dispenser at predetermined positions located away from the platform. A doctor blade contacts the composition transferred above the free surface, and then moves over the platform to form a substantially uniform layer of the composition.

Claims

1. In an apparatus for fabricating an integral three-dimensional object by selectively exposing successive layers of a liquid photoformable composition to actinic radiation, said apparatus including imaging means for exposing said layers, a vessel for containing a fixed amount of said composition so as to present a free surface at a substantially constant position relative to said imaging means, and a movable platform disposed within said vessel below said free surface, the improvement in said apparatus comprising:

a dispenser adapted to be dipped under said free surface and directly transfer part of said composition above said free surface;

means attached to said dispenser for lowering and raising said dispenser at predetermined positions alongside said platform; and

layering means for contacting the composition transferred above said free surface and moving over said platform to form a layer of said composition.

2. An apparatus as defined in claim 1 wherein said dispenser comprises a trough having a slot disposed at the bottom thereof.

3. An apparatus as defined in claim 2 wherein said dispenser further comprises a valve adapted to control the flow of composition through said slot.

4. An apparatus as defined in claim 1 wherein said dispenser comprises a trough pivotally connected to a hinge.

5. An apparatus as defined in claim 1 wherein said dispenser comprises a plurality of parallel plates connected at one end thereof.

6. An apparatus as defined in claim 1 wherein said dispenser comprises two plates pivotally connected by a pair of pivoting pins so as to form a V-shaped pocket.

7. An apparatus as defined in claim 1 wherein said dispenser comprises a single plate.

8. An apparatus as defined in claim 7 wherein said plate has a plurality of pockets disposed along a side thereof, each pocket having a hole at the bottom thereof.

9. An apparatus as defined in claim 7 wherein said dispenser further comprises a wiper for wiping composition off from said plate.

10. An apparatus as defined in claim 1 wherein said layering means comprises a doctor blade.

11. An apparatus as defined in claim 10 wherein said dispenser is incorporated as part of said doctor blade.

12. An apparatus as defined in claim 11 wherein said dispenser comprises a trough attached to one side of said doctor blade, said trough having a slot disposed at the bottom thereof to form a dispensing tip in common with the bottom portion of said blade.

13. An apparatus as defined in claim 10 wherein said dispenser comprises a plate disposed within said composition and attached to means for providing an upward pulse for transferring part of said composition adjacent said doctor blade.

14. An apparatus as defined in claim 1 wherein said layering means comprises two doctor blades positioned so that said dispenser is located between said blades.

15. An apparatus as defined in claim 1 wherein said means for raising and lowering said dispenser comprises a rail cam.

16. An apparatus for fabricating an integral three-dimensional object from a multiplicity of cross sectional portions of the object, the cross sectional portions corresponding to solidified portions of contiguous layers of a photoformable liquid composition, comprising an assembly of:

imaging means for imagewise exposing to radiation each of the contiguous layers of the photoformable composition; and

a coating station comprising

a vessel for containing a fixed amount of said liquid photoformable composition, said composition presenting a free surface at a substantially constant position relative to said imaging means;

a substantially flat platform disposed within said vessel, said platform having sides and adapted to be positioned below the free surface of said composition;

placement means for controllably varying the distance between the free surface of said composition and said platform;

a dispenser adapted to be dipped under the free surface of said composition and directly transfer part of said composition above the free surface of said composition;

means for raising and lowering said dispenser at predetermined positions and time periods; and

layering means for producing a layer from the transferred part of said composition.

17. In a method for fabricating an integral three-dimensional object by utilizing imaging means to selectively expose successive layers of a liquid photoformable composition to actinic radiation, said method including containing a fixed amount of said composition within a vessel so as to present a free surface at a substantially constant position relative to said imaging means, and moving a platform disposed within said vessel below said free surface, the improvement in said method comprising:

transferring part of said composition above said free surface by lowering and raising a dispenser at predetermined positions alongside said platform, said dispenser adapted to be dipped under said free surface;

contacting the composition transferred above said free surface with a layering means; and

moving said layering means over said platform to level said transferred composition so as to form a substantially uniform layer of said composition.

18. A method as recited in claim 17 further comprising the steps of keeping said dispenser at least partially dipped below the free surface of said composition during the exposing step.

19. A method as recited in claim 17 wherein said moving step is performed by moving said layering means over said platform at a distance less than 5 mm above the free surface of said composition.

20. A method as recited in claim 19 wherein said layering means comprises two doctor blades, and wherein said transferring step is performed by a dispenser located between said two doctor blades.

21. A method as recited in claim 19 wherein said layering means comprises a doctor blade.

22. A method as recited in claim 21 wherein said dispenser comprises a plate disposed within said composition, and wherein said transferring step is performed by providing an upward pulse to said plate so as to transfer part of said composition adjacent said doctor blade.

23. A method as recited in claim 17 wherein the step of lowering and raising said dispenser is performed by a rail cam attached thereto.

24. A method for fabricating an integral three-dimensional object from a multiplicity of cross sectional portions of the object by utilizing imaging means to selectively expose successive layers of a liquid photoformable composition, the cross sectional portions corresponding to solidified portions of contiguous layers of said photoformable liquid composition, comprising the steps of:

placing a fixed amount of the liquid photoformable composition in a vessel, said composition presenting a free surface at a substantially constant position relative to said imaging means;

positioning a substantially flat platform within said vessel so that said platform is disposed below the free surface of said composition;

lowering said platform in said composition by the thickness of a layer;

dispensing part of said composition on top of said free surface by a dip and raise motion of a dispenser;

leveling the transferred part of said composition over said platform to form a substantially uniform layer of photoformable composition;

exposing imagewise at least a portion of said uniform liquid layer to actinic radiation in order to produce a respective cross sectional portion of the object; and

successively repeating said lowering, dispensing, leveling and exposing steps until the three-dimensional object is complete.

25. In an apparatus for fabricating an integral three-dimensional object by selectively exposing successive layers of a liquid photoformable composition to actinic radiation, said apparatus including a vessel for containing said composition so as to present a free surface, and a movable platform disposed within said vessel below said free surface, the improvement in said apparatus comprising:

a dispenser adapted to be dipped under said free surface and directly transfer part of said composition above said free surface;

means attached to said dispenser for lowering and raising said dispenser at predetermined positions alongside said platform; and

layering means for contacting the composition transferred above said free surface and moving over said platform to form a layer of said composition.

26. An apparatus for fabricating an integral three-dimensional object from a multiplicity of cross sectional portions of the object, the cross sectional portions corresponding to solidified portions of contiguous layers of a photoformable liquid composition, comprising an assembly of:

imaging means for imagewise exposing to radiation each of the contiguous layers of the photoformable composition; and

a coating station comprising

a vessel for containing said liquid photoformable composition, said composition presenting a free surface;

a substantially flat platform disposed within said vessel, said platform having sides and adapted to be positioned below the free surface of said composition;

placement means for controllably varying the distance between the free surface of said composition and said platform;

a dispenser adapted to be dipped under the free surface of said composition and directly transfer part of said composition above the free surface of said composition;

means for raising and lowering said dispenser at predetermined positions and time periods; and

layering means for producing a layer from the transferred part of said composition.

27. In a method for fabricating an integral three-dimensional object by selectively exposing successive layers of a liquid photoformable composition to actinic radiation, said method including containing said composition within a vessel so as to present a free surface, and moving a platform disposed within said vessel below said free surface, the improvement in said method comprising:

transferring part of said composition above said free surface by lowering and raising a dispenser at predetermined positions alongside said platform, said dispenser adapted to be dipped under said free surface;

contacting the composition transferred above said free surface with a layering means; and

moving said layering means over said platform to level said transferred composition so as to form a substantially uniform layer of said composition.

28. A method for fabricating an integral three-dimensional object from a multiplicity of cross sectional portions of the object, the cross sectional portions corresponding to solidified portions of contiguous layers of a photoformable liquid composition, comprising the steps of:

placing the liquid photoformable composition in a vessel, said composition presenting a free surface;

positioning a substantially flat platform within said vessel so that said platform is disposed below the free surface of said composition;

lowering said platform in said composition by the thickness of a layer;

dispensing part of said composition on top of said free surface by a dip and raise motion of a dispenser;

leveling the transferred part of said composition over said platform to form a substantially uniform layer of photoformable composition;

exposing imagewise at least a portion of said uniform liquid layer to actinic radiation in order to produce a respective cross sectional portion of the object; and

successively repeating said lowering, dispensing, leveling and exposing steps until the three-dimensional object is complete.