Method and apparatus for 3D printing by selective sintering

Patent metadata

Field	Value
Publication number	US-10994333-B2
Application number	US-201515304873-A
Country	US
Kind code	B2
Filing date	May 7, 2015
Priority date	May 8, 2014
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A system (100) for building a three dimensional object includes a powder delivery station (10) for applying a layer of powder material on a building tray (200), a digital printing station (30) for printing a mask pattern on the layer, a sintering station (50) for selectively sintering the portion of the layer that is defined by the mask to be sintered and a stage (250) for repeatedly advancing the building tray (200) to each of the powder delivery station, digital printing station and sintering station to build a plurality of layers that together form the three dimensional object. The mask pattern defines a negative portion of the layer to be sintered. Optionally, the system includes a die compaction station (40) for compacting per layer of powder material.

First claim

What is claimed is:

1. A system for building a three dimensional object comprising:
a powder delivery station for applying a layer of powder material on a building tray;
a digital printing station for printing a mask pattern on the layer, wherein the mask pattern defines a negative of a portion of the layer to be sintered;
a thermal mass roller configured to sinter the portion of the layer that is defined by the mask pattern to be sintered as it is rolled on the layer and to apply pressure to the layer to promote adhesion between the layer and a previous layer, wherein the thermal mass roller is stationed in a sintering station and wherein the sintering station includes an anti-peeling mechanism, the anti-peeling mechanism including a foil positioned between the thermal mass roller and the layer; and
a stage for repeatedly advancing the building tray to each of the powder delivery station, digital printing station and sintering station to build a plurality of layers that together form the three dimensional object.

2. The system according to claim 1 , comprising a die compacting station for compacting the layer of powder material, wherein the compacting station includes a die for receiving the layer.

3. The system according to claim 2 , wherein the die compacting station includes a heating element for warming a surface of the die that interfaces with the layer.

4. The system according to claim 2 , wherein the die compacting station is operable to apply up to 100 MPa of pressure on the layer and wherein the die compacting station includes a lifting system for lifting the building tray toward the die.

5. The system according to claim 2 , wherein the die compacting station includes an anti-peeling mechanism, the anti-peeling mechanism including a foil positioned between the building tray and the die, wherein the foil is supported by two opposite edges to allow bowing of the foil during separation between the building tray and the die.

6. The system according to claim 1 , comprising a cooling station for cooling the layer after sintering, wherein the cooling station includes air knives for providing jet stream of gas.

7. The system according to claim 1 , wherein the digital printing station is operable to dispense ink including a frit suspended in a liquid carrier, wherein the frit is formed from particles having a diameter of between 500 nm to 1 μm.

8. The system according to claim 1 , wherein the thermal mass roller is configured to be heated to 0°-80° C. above the melting temperature of the powder.

9. The system according to claim 1 , wherein the thermal mass roller is configured to apply a pressure in the order of magnitude of 20-180 N/cm of roller length.

10. The system according to claim 1 , wherein the sintering station includes an array of vertical-cavity surface-emitting lasers (VCSEL) that swept over the layer for pre-heating.

11. The system according to claim 1 , wherein the building tray includes at least one channel running substantially parallel to a surface of the tray on which the layer is positioned, through which fluid is introduced for cooling the building tray.

12. The system according to claim 1 , wherein the powder is aluminum or aluminum alloy powder.

13. The system of claim 1 , comprising a powder spreading station, wherein the powder spreading station includes a spreading roller configured to spread a layer of powder dispensed in the powder delivery station and wherein the spreading roller is other than the thermal mass roller.

14. A system for building a three dimensional object comprising:
a powder delivery station for applying a layer of powder material on a building tray;
a digital printing station for printing a mask pattern on the layer, wherein the mask pattern defines a negative of a portion of the layer to be sintered;
a die compacting station for compacting the layer of powder material, wherein the compacting station includes a die for receiving the layer, wherein the die compacting station includes an anti-peeling mechanism, the anti-peeling mechanism including a foil positioned between the building tray and the die, wherein the foil is supported by two opposite edges to allow bowing of the foil during separation between the building tray and the die; and
a thermal mass roller configured to sinter the portion of the layer that is defined by the mask pattern to be sintered as it is rolled on the layer and to apply pressure to the layer to promote adhesion between the layer and a previous layer, wherein the thermal mass roller is stationed in a sintering station; and
a stage for repeatedly advancing the building tray to each of the powder delivery station, digital printing station and sintering station to build a plurality of layers that together form the three dimensional object.

15. The system according to claim 14 , wherein the die compacting station includes a heating element for warming a surface of the die that interfaces with the layer.

16. The system according to claim 14 , wherein the die compacting station is operable to apply up to 100 MPa of pressure on the layer and wherein the die compacting station includes a lifting system for lifting the building tray toward the die.

17. The system according to claim 14 , comprising a cooling station for cooling the layer after sintering, wherein the cooling station includes air knives for providing jet stream of gas.

18. The system according to claim 14 , wherein the powder is aluminum or aluminum alloy powder.

Assignees

• Stratasys Ltd

Inventors

• Sheinman Yehoshua

Classifications

• B22F12/63

  Rollers · CPC title

• B22F12/41

  characterised by the type, e.g. laser or electron beam · CPC title

• B22F12/20

  Cooling means · CPC title

• B22F12/13

  to preheat the material · CPC title

• B22F10/68

  Cleaning or washing · CPC title