Control of particle layer depth and thickness during powder printing

Patent metadata

Field	Value
Publication number	US-10814649-B2
Application number	US-201816210656-A
Country	US
Kind code	B2
Filing date	Dec 5, 2018
Priority date	Dec 5, 2018
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A printing system includes a liquid ejector configured to deposit a curable layer on a surface of a substrate, the layer having a free surface and an interface between the layer and the substrate. A pre-curing device pre-cures the layer such that a first region closer to the free surface is less cured than a second region closer to the interface. The curing device includes a pre-curing initiator source configured to provide a pre-curing initiator that polymerizes the layer. The curing device also includes a pre-curing inhibitor source configured to deliver an inhibitor that inhibits polymerization of the layer. A particle delivery device delivers particles to the layer after the layer is pre-cured.

First claim

What is claimed is:

1. A printing system comprising:
a liquid ejector configured to deposit a curable layer on a surface of a substrate, the layer having a free surface and an interface between the layer and the substrate;
a pre-curing device configured to pre-cure the layer such that a first region closer to the free surface is less cured than a second region closer to the interface, the pre-curing device comprising:
a pre-curing initiator source configured to provide a pre-curing initiator that polymerizes the layer; and
a pre-curing inhibitor source configured to deliver an inhibitor that inhibits polymerization of the layer;

a particle delivery device configured to deliver particles to the layer after the layer is pre-cured.

2. The system of claim 1 , wherein:
the pre-curing initiator source comprises an ultraviolet (UV) radiation source configured to generate UV radiation; and
further comprising a controller configured to control an intensity of the UV radiation.

3. The system of claim 1 , wherein:
the pre-curing inhibitor source comprises an oxygen source configured to deliver oxygen; and
further comprising a controller configured to control a concentration of oxygen.

4. The system of claim 1 , further comprising a curing device configured to substantially cure the first region of the layer after the particles have been delivered to the free surface of the layer.

5. The system of claim 1 , further comprising one or both of a heat source and a heated roller configured to heat the free surface of the layer after the particles have been delivered.

6. The system of claim 1 , wherein the pre-curing device is configured to provide a spatial pattern of the pre-curing initiator that extends along one or both of a lateral axis and a longitudinal axis of the layer, wherein the spatial pattern of the pre-curing initiator provides one or more first areas with a first amount of the pre-curing initiator and provides one or more second areas with a different second amount of the pre-curing initiator.

7. The system of claim 6 , wherein:
the pre-curing initiator source comprises an array of UV radiation sources and the pre-curing initiator comprises UV radiation; and
further comprising a controller configured to independently modulate an intensity of each of the UV radiation sources to provide the spatial pattern of the UV radiation.

8. The system of claim 6 , wherein the pre-curing device comprises:
at least one UV radiation source configured to provide the pre-curing initiator comprising UV radiation; and
a spatial patterning device optically coupled to the at least one UV radiation source, the at least one UV radiation source and the spatial patterning device configured to provide a spatial pattern of UV radiation.

9. The system of claim 1 , further comprising a pre-curing initiator patterning device configured to produce a gradient of the pre-curing initiator with respect to one or both of a lateral axis and a longitudinal axis of the free surface.

10. The system of claim 9 , wherein the spatial patterning device is a moveable shutter.

11. The system of claim 1 , further comprising a pre-curing inhibitor patterning device configured to provide a spatial pattern of a pre-curing inhibitor provided by the pre-curing inhibitor patterning device.

12. A method, comprising:
depositing a curable layer on a surface of a substrate, the layer having a free surface and an interface between the layer and the substrate;
pre-curing the layer such that a first region closer to the interface of the layer is more cured than a second region closer to the free surface of the layer and that the first region is located a predetermined distance from the free surface; and
delivering particles to the free surface of the layer after pre-curing the layer such that a depth of the particles is limited by the predetermined distance from the free surface.

13. The method of claim 12 , further comprising curing the layer after the particles have been delivered to the free surface.

14. The method of claim 12 , wherein pre-curing the layer comprises directing a pre-curing gas toward the free surface in the presence of a pre-curing inhibitor.

15. The method of claim 14 , further comprising controlling pre-curing of the layer comprising controlling one or more of an intensity of the UV radiation, a concentration of the oxygen, and a temperature of the layer such that the first region is located a predetermined distance from the free surface.

16. The method of claim 12 , wherein pre-curing the layer comprises directing UV radiation toward the free surface in the presence of oxygen.

17. The method of claim 12 , wherein pre-curing the layer comprises at least one of:
generating a spatial pattern of a pre-curing initiator, the spatial pattern configured to pattern the second region along at least one of a lateral axis and a longitudinal axis of the layer; and
generating a gradient of the pre-curing initiator with respect to one or both of a lateral axis and a longitudinal axis of the free surface.

18. The method of claim 17 , further comprising at least one of:
controlling a thickness of a band of the particles in the layer;
reorienting the particles after delivering the particles to the free surface of the layer; and
modifying a surface roughness of the free surface after delivering the particles to the free surface of the layer.

19. The method of claim 12 , wherein pre-curing the layer and delivering the particles to the free surface comprise controlling the depth of the particles in the layer.

20. The method of claim 12 , wherein:
delivering the particles to the free surface of the layer after pre-curing the layer comprises a delivering a second type of particles; and
further comprising delivering a first type of particles to the free surface of the layer before pre-curing the layer.

Assignees

• Palo Alto Res Ct Inc

Inventors

• Jackson Warren B
• Evans Kent A
• Doris Sean E

Classifications

• B41J2/2117 Primary

  Ejecting white liquids · CPC title

• B33Y30/00 Primary

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• C09D11/30

  Inkjet printing inks · CPC title

• B33Y50/02

  for controlling or regulating additive manufacturing processes · CPC title

• B29C64/295

  Heating elements · CPC title