Electrostatic powder remover for powder bed fusion additive manufacturing

1 . A system for removing an upper layer of powder from a powder bed in an additive manufacturing process, wherein the powder bed includes metal powder particles, and the additive manufacturing process is being used to build a part, the system comprising:

a controller;

an electrode subsystem having an electrode and a dielectric layer secured to the electrode;

a metallic build plate for supporting the powder bed thereon;

the electrode subsystem being supported above the powder bed such that the dielectric layer is separated from an upper surface of the powder bed by a gap of a predetermined distance;

a motion control subsystem responsive to the controller and configured to control a spacing between a lower surface of the electrode subsystem and the powder bed, such that the spacing is maintained at a predetermined distance as successive layers of the part are formed;

a power source coupled to the electrode subsystem and the build plate for supplying a voltage across the electrode subsystem and the build plate, the voltage generating an electric field in the gap which is sufficient to attract and lift a predetermined thickness portion of the powder bed adjacent the upper layer, onto the dielectric layer, across an entire area defined by the electrode subsystem, below the electrode subsystem, at one time, to leave a new upper surface on the powder bed; and

wherein the electrode subsystem comprises a planar configuration arranged parallel to the upper surface of the powder bed, and having dimensions sufficient to cover a major portion of the build plate.

2 . The system of claim 1 , wherein the power source comprises a DC voltage source.

3 . The system of claim 1 , wherein the electrode subsystem has an area sufficient to cover the powder bed, and is stationary while the electric field is being generated.

4 . The system of claim 1 , wherein the electrode subsystem comprises a planar configuration having an area less than an area of the upper surface of the powder bed.

5 . The system of claim 4 , further comprising a movement subsystem for moving the electrode subsystem over the upper surface of the powder bed, parallel to the upper surface of the powder bed, while maintaining the gap, and while the electric field is being generated.

6 . The system of claim 1 , further comprising:

a movement subsystem;

wherein the electrode of the electrode subsystem comprises a cylindrical electrode subsystem, wherein the electrode comprises a cylindrical electrode, and the dielectric layer comprises a dielectric layer conforming to a shape of the cylindrical electrode; and

the movement subsystem configured to move the cylindrical electrode subsystem rotationally above and over the surface of the powder bed while maintaining the gap.

7 . The system of claim 1 , wherein the electrode comprises a thickness of no more than 5 mm.

8 . The system of claim 1 , wherein the dielectric layer comprises a thickness of no more than about 3 mm.

9 . The system of claim 1 , wherein the electrode is comprised of an electrically conductive material including at least one of: gold; silver; copper, steel; stainless steel; aluminum; and iron.

10 . The system of claim 1 , wherein the dielectric layer is comprised of at least one of polypropylene or polycarbonate.

11 . The system of claim 1 , wherein the electric field comprises a strength of between about 0.3×10 7 V/m to about 0.4×10 7 V/m.

12 . The system of claim 1 , where the powder bed forms a powder bed in a laser powder bed fusion (LPBF) additive manufacturing (AM) operation.

13 . A system for removing an upper layer of powder from a powder bed, where the powder bed is being used in a laser powder bed fusion (LPBF) additive manufacturing (AM) operation to form a part in a layer-by-layer operation, the system comprising:

a controller;

an electrode subsystem having a planar electrode and a planar dielectric layer secured to the planar electrode;

an electrically conductive build plate for supporting the powder bed thereon;

the electrode subsystem being supported above the powder bed such that the dielectric layer is separated from an upper surface of the powder bed by a gap of a predetermined, uniform distance;

a motion control subsystem responsive to the controller and configured to control a spacing between a lower surface of the electrode subsystem and the powder bed, such that the spacing is maintained at a predetermined distance as successive layers of the part are formed;

a DC power source coupled to the electrode subsystem and the build plate for supplying a DC voltage across the electrode subsystem and the build plate, the voltage generating an electric field in the gap which is sufficient to attract and lift a predetermined thickness portion of the powder bed adjacent the upper surface, onto the dielectric layer, over a full area underneath the electrode subsystem, defined by the electrode subsystem, at one time, to leave a new upper surface on the powder bed; and

wherein the electrode subsystem comprises a planar configuration arranged parallel to the upper surface of the powder bed, and having dimensions sufficient to cover a major portion of the build plate.

14 . The system of claim 13 , wherein the electrode subsystem is held stationary while the electric field is being generated.

15 . The system of claim 13 , further comprising:

a movement subsystem for moving the electrode subsystem;

wherein the electrode subsystem has an area which is less than an entire area of the upper surface of the powder bed; and

wherein the movement subsystem is configured to move the electrode subsystem over the upper surface, parallel to the upper surface, while the electric field is being generated, such that the electrode subsystem traverses the entire area of the upper surface of the powder bed.

16 . The system of claim 13 , wherein the dielectric layer comprises a thickness of no more than about 5 mm.

17 . The system of claim 13 , wherein the electrode comprises at least one of gold; silver; copper, steel; stainless steel; aluminum; or iron.

18 . The system of claim 13 , wherein the dielectric layer comprises at least one of polypropylene or polycarbonate.

19 . A method for removing an upper surface layer of powder from a powder bed, wherein the powder bed includes metal powder particles used to form a part in a layer-by-layer, additive manufacturing operation, the method comprising:

providing a controller;

using a metallic build plate to support the powder bed thereon;

arranging an electrode subsystem having an electrode and a dielectric layer secured to the electrode above an upper surface of the powder bed, wherein the electrode subsystem is separated from the upper surface layer of the powder bed by a gap having a predetermined distance;

using a motion control subsystem responsive to the controller and configured to control a spacing between a lower surface of the electrode subsystem and the powder bed, such that the spacing is maintained at a predetermined distance as successive layers of the part are formed;

applying an electrical signal across the electrode subsystem and the metallic build plate to generate an electric field in the gap below the electrode subsystem, defined by an area of the electrode subsystem;

using the electric field to lift a portion of the powder bed adjacent the upper surface layer of the powder bed, onto the dielectric layer, to create a new surface layer for the powder bed; and

wherein the electrode subsystem comprises a planar configuration arranged parallel to the upper surface of the powder bed, and having dimensions sufficient to cover a major portion of the build plate.

20 . The method of claim 19 , further comprising moving the electrode subsystem over the upper surface layer of the powder bed, while maintaining the gap, and while the electric field is being generated.