Method and apparatus for additive manufacturing with powder material

1. A system for building a three dimensional green compact on a building tray, the system comprising:

a printing station comprising:

a printing head configured to selectively dispense a photocurable material on the building tray to form a mask pattern; and

a curing unit configured to photocure the mask pattern that is formed on the building tray;

a powder delivery station configured to deliver a layer of powder material on the cured mask pattern;

a die compacting station for compacting the powder material and the cured mask pattern; and

a precision stage configured to repeatedly advance the building tray to each of the printing station, the powder delivery station and the die compacting station to build a plurality of layers that together form the three dimensional green compact.

2. The system according to claim 1 , wherein the curing unit is configured to cure the photocurable material with UV light.

3. The system according to claim 1 , wherein the die compacting station includes side walls that are configured to be introduced around the building tray based on contact of the layer with the compacting station.

4. A system for forming a three dimensional object comprising:

a system for building a three dimensional green compact according to claim 1 ; and

a post-processing station selected from the group consisting of a second compacting station, a heating station, a sintering station, and any combination thereof.

5. A method for building a three dimensional green compact, the method comprising:

printing a mask pattern on a building tray wherein the printing comprises:

selectively dispensing a photocurable material on the building tray; and

photocuring the photocurable material to form a mask pattern;

delivering powder material over the mask pattern to form a layer of the green compact;

compacting the layer; and

repeating the printing, delivering and compacting until the three dimensional green compact is completed.

6. The method according to claim 5 , wherein delivering powder material comprises:

dispensing a plurality of rows of powder material; and

spreading the plurality of rows of powder material with a roller that is actuated to both rotate and move across the layer.

7. The method according to claim 6 , wherein the plurality of rows of powder material is positioned perpendicular to a spreading direction.

8. The method according to claim 6 comprising at least one of: inverting the spreading direction from one powder layer to the subsequent one; and varying the positioning of the plurality of rows of powder material from one powder layer to the subsequent one.

9. The method according to claim 5 , further comprising collecting excess powder material falling from the edges of the building tray during the spreading and recirculating the excess powder material to a powder hopper.

10. The method according to claim 9 , comprising:

suctioning the excess powder material to at least one cyclone separator;

separating the powder material from air in the at least one cyclone separator;

filtering the powder material from the at least one cyclone separator with a mesh; and

delivering powder material filtered through the mesh to a powder hopper, wherein the powder hopper provides the powder material for building the three dimensional green compact.

11. The method according to claim 5 , wherein the printing, delivering and compacting are performed at ambient temperatures.

12. The method according to claim 5 , wherein a first layer is formed on a building tray coated with a tacky material.

13. A method for forming a three dimensional object comprising:

building a three dimensional green compact according to the method of claim 5 , wherein said three dimensional green compact comprises an object and a support region including photocurable material; and

post-processing the green compact by:

removing the photocurable material;

separating the object from the support region; and

sintering the object.

14. The method according to claim 13 , wherein post-processing further comprises compacting the green compact as a whole.

15. The system according to claim 1 comprising a controller configured to coordinate operation of each of the printing station, the powder delivery station and a die compacting station with positioning of the building tray on the precision stage, wherein the precision stage is an X stage.

16. The system according to claim 15 , wherein the printing head and curing unit are supported on a Y stage, the Y stage moving perpendicular to the X stage and wherein the controller is configured to coordinate with positioning of the building tray with the positioning the Y stage during operation of the printing station.

17. The system according to claim 1 , wherein the printing head is supported on an X-Y stage.

18. The system according to claim 1 , wherein the printing head is an inkjet printing head including an array of nozzles through which the photocurable material is selectively deposited.

19. The system according to claim 1 , wherein the powder delivery station comprises:

a powder dispenser configured to dispense a plurality of rows of powder material per layer;

a roller that is actuated to rotate while moving across the building tray to spread the powder material per layer; and

gutters positioned around the building tray.

20. The method of claim 5 , wherein the mask pattern is printed with an inkjet printing head including an array of nozzles through which the photocurable material is selectively dispensed.

21. The system according to claim 1 , wherein the photocurable material is a photopolymer material.

22. A system for building a three dimensional green compact on a building tray, the system comprising:

a printing station comprising:

a printing head configured to selectively dispense a photopolymer material on the building tray to form a mask pattern; and

a curing unit configured to cure with UV light the photopolymer material forming the mask pattern on the building tray;

a powder delivery station configured to deliver a layer of powder material on the cured mask pattern;

a die compacting station for compacting the powder material and the cured mask pattern; and

a precision stage configured to repeatedly advance the building tray to each of the printing station, the powder delivery station and the die compacting station to build a plurality of layers that together form the three dimensional green compact.