Defect mitigation for recoating systems for additive manufacturing
Disclosed embodiments relate to recoater systems for use with additive manufacturing systems. A recoater assembly may be used to deposit a material layer onto a build surface of an additive manufacturing system. In some instances, the recoater assembly may include a powder entrainment system that trails behind a recoater blade of the recoater assembly relative to a direction of motion of the recoater blade across a build surface of the additive manufacturing system. The powder entrainment system may generate a flow of fluid across a portion of the build surface behind the recoater blade that at least temporarily entrains powder above a threshold height from the build surface to mitigate, or prevent, the formation of defects on the build surface with heights greater than the threshold height.
1. A method of recoating a build surface of an additive manufacturing system, the method comprising:
depositing powder onto the build surface with a recoater assembly; and
flowing a fluid across at least a portion of the build surface with a velocity profile that increases with increasing distance from the build surface, and
entraining powder above a threshold height from the build surface in the flow of fluid.
2. The method of claim 1 , wherein flowing the fluid across the build surface includes flowing the fluid across the build surface behind a path of travel of the recoater assembly.
3. The method of claim 1 , wherein a velocity of at least a portion of the flow of fluid is between or equal to 0.1 meters per second (m/s) and 2.0 m/s at a height from the build surface that is between or equal to 0.5 millimeters (mm) and 10.0 mm.
4. The method of claim 1 , further comprising generating the flow of fluid by moving a movable surface relative to the build surface.
5. The method of claim 4 , wherein a portion of the movable surface oriented towards the build surface moves in a direction of motion of the recoater assembly.
6. The method of claim 4 , wherein a portion of the movable surface oriented towards the build surface moves in a direction that is opposite a direction of motion of the recoater assembly.
7. The method of claim 4 , wherein a plurality of surface features with varying heights are disposed on the movable surface.
8. The method of claim 4 , further comprising disrupting a boundary layer of the fluid adhered to the movable surface.
9. The method of claim 8 , wherein disrupting the boundary layer of the fluid comprises disrupting the boundary layer using a mask.
10. The method of claim 9 , wherein the mask is contoured to at least a portion of the movable surface.
11. The method of claim 9 , wherein the mask is disposed adjacent to the movable surface at a distance that is less than a thickness of the boundary layer of the fluid adhered to the movable surface.
12. The method of claim 4 , wherein moving the movable surface comprises rotating a rotatable roller about an axis of rotation of the rotatable roller that is parallel to the build surface.
13. The method of claim 4 , wherein moving the movable surface comprises moving a belt, and wherein moving the belt includes moving at least a portion of the belt parallel to the build surface.
14. The method of claim 4 , wherein moving the movable surface comprises rotating a plurality of rotatable disks.
15. The method of claim 14 , wherein the plurality of rotatable disks is arranged in an array.
16. The method of claim 1 , further comprising removing powder entrained in the fluid from the additive manufacturing system.
17. A method of recoating a build surface of an additive manufacturing system, the method comprising:
moving a recoater blade across a layer of powder deposited on a build surface of the additive manufacturing system;
trailing a powder entrainment system behind the recoater blade relative to a direction of motion of the recoater blade across the build surface; and
moving a movable surface of the powder entrainment system relative to a proximate portion of the build surface at a first velocity that is different from a second velocity of the recoater blade relative to the build surface.
18. The method of claim 17 , wherein the first velocity is between or equal to 0.1 meters per second (m/s) and 2.0 m/s, and wherein at least a portion of the movable surface is disposed at a height from the build surface that is between or equal to 0.5 millimeters (mm) and 10.0 mm.
19. The method of claim 17 , further comprising moving a portion of the movable surface oriented towards the build surface in the direction of motion of the recoater blade.
20. The method of claim 17 , further comprising moving a portion of the movable surface oriented towards the build surface in a direction that is opposite to the direction of motion of the recoater blade.
21. The method of claim 17 , wherein a plurality of surface features with varying heights are disposed on the movable surface.
22. The method of claim 17 , further comprising disrupting a boundary layer of the fluid adhered to the movable surface.
23. The method of claim 17 , wherein moving the movable surface comprises rotating a rotatable roller about an axis of rotation of the rotatable roller that is parallel to the build surface.
24. The method of claim 17 , wherein moving the movable surface comprises moving a belt, and wherein moving the belt includes moving at least a portion of the belt parallel to the build surface.
25. The method of claim 17 , wherein moving the movable surface comprises rotating a plurality of rotatable disks.
26. The method of claim 25 , wherein the plurality of rotatable disks is arranged in an array.