TUNING PNEUMATIC JETTING OF METAL FOR ADDITIVE MANUFACTURING

• US 20170252809A1
• Filed: 03/03/2017
• Published: 09/07/2017
• Est. Priority Date: 03/03/2016
• Status: Abandoned Application

• Current Assignee: Desktop Metal, Inc.
• Original Assignee: Desktop Metal, Inc.
• Inventors: Myerberg, Jonah Samuel, Natchurivalapil Rappai James, Toshana Krishna, Sachs, Emanuel Michael, Hoisington, Paul A., Li, Kevin Michael
• Application Number:
  US15/449,575
• Publication Number:
  US 20170252809A1
• Time in Patent Office: Days
• CPC Class Codes: B22F 10/22 Direct deposition of molten metal
• CPC Class Codes: B22F 10/32 of the atmosphere, e.g. composition or pressure in a building chamber
• CPC Class Codes: B22F 12/10 Auxiliary heating means
• CPC Class Codes: B22F 12/22 Driving means
• CPC Class Codes: B22F 12/53 Nozzles
• CPC Class Codes: B22F 2009/0892 casting nozzle; controlling metal stream in or after the casting nozzle
• CPC Class Codes: B22F 2202/05 Use of magnetic field
• CPC Class Codes: B22F 2203/13 pressure
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/003 Apparatus, e.g. furnaces in general F27B
• CPC Class Codes: B22F 3/115 by spraying molten metal, i.e. spray sintering, spray casting
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

Devices, systems, and methods are directed to adjusting a pneumatic circuit associated with pneumatic ejection of liquid metal from a nozzle as the nozzle moves along a controlled three-dimensional pattern to fabricate a three-dimensional object. The adjustment of the pneumatic circuit can facilitate adjusting a pressure profile within the nozzle as pressurized gas moves through the nozzle to eject, through pneumatic force, liquid metal from the nozzle. Through adjustment of the pneumatic circuit, characteristics of the liquid metal (e.g., size, shape, and flow rate) can be controlled to facilitate control over fabrication of the three-dimensional object.

Claims

1. An additive manufacturing system, the system comprising:

a nozzle defining a volume and a discharge orifice in fluid communication with one another, the nozzle including an exhaust passage in fluid communication with the volume;

a source of a pressurized gas in selective fluid communication with the volume of the nozzle; and

a media supply in fluid communication with the volume of the nozzle such that metal from the media supply is movable into the volume, wherein the exhaust passage has an adjustable back pressure to control a pressure profile in the volume of the nozzle as the pressurized gas moves through the volume to eject a liquid form of the metal from the discharge orifice along a controlled three-dimensional pattern for fabrication of a three-dimensional object.

2. The system of claim 1, wherein the exhaust passage includes a hydraulic inductance, the hydraulic inductance having a dissipating resistance to flow in response to force exerted, over a period of time, on the hydraulic inductance by venting pressurized gas in the exhaust passage.

3. The system of claim 2, wherein the hydraulic inductance includes a paddle wheel rotatable in response to force exerted on the paddle wheel by venting pressurized gas in the exhaust passage.

4. The system of claim 2, a paddle wheel rotatable in response to force exerted on the paddle wheel by venting pressurized gas in the exhaust passage.

5. The system of claim 2, wherein a time-varying profile of the resistance of the hydraulic inductance is adjustable.

6. The system of claim 1, wherein the exhaust passage includes a variable hydraulic resistance.

7. The system of claim 6, wherein the variable hydraulic resistance includes a variable length of the exhaust passage.

8. The system of claim 6, wherein the variable hydraulic resistance includes a flow restriction having a variable size.

9. The system of claim 1, further comprising a valve in fluid communication with the source of the pressurized gas and the volume, the valve actuatable to deliver pulses of the pressurized gas to the volume.

10. A method of additive manufacturing, the method comprising:

directing a metal into a volume defined by a nozzle, the volume in fluid communication with an exhaust passage defined by the nozzle;

moving a discharge orifice and a build plate relative to one another along a controlled three-dimensional pattern, the discharge orifice defined by the nozzle and in fluid communication with the volume;

delivering pulses of pressurized gas into the volume of the nozzle; and

adjusting a back pressure of the exhaust passage through which the pressurized gas is vented from the volume of the nozzle, wherein, in response to the adjustment of the back pressure, the pressurized gas in the volume exerts a force on a liquid form of the metal in the nozzle to eject the liquid metal from the discharge orifice as the discharge orifice and the build plate are moved relative to one another along the controlled three-dimensional pattern to form a three-dimensional object on the build plate.

11. The method of claim 10, wherein adjusting the back pressure of the exhaust passage includes venting the pressurized gas through a hydraulic inductance having a dissipating resistance to flow in response to force exerted, over a period of time, on the hydraulic inductance by the venting pressurized gas in the exhaust passage.

12. The method of claim 11, wherein the dissipating resistance dissipates to a substantially constant hydraulic resistance over the period of time.

13. The method of claim 12, wherein the period of time is less than a period of the pulses of pressurized gas delivered into the volume of the nozzle.

14. The method of claim 11, wherein the hydraulic inductance includes a paddle wheel rotatable in response to force exerted on the paddle wheel by the venting pressurized gas in the exhaust passage.

15. The method of claim 10, wherein adjusting the back pressure of the exhaust passage includes venting the pressurized gas through a variable hydraulic resistance and adjusting the variable hydraulic resistance based at least in part on a position of the discharge orifice with respect to the controlled three-dimensional pattern.

16. The method of claim 15, wherein the variable hydraulic resistance includes a flow restriction having a variable size and varying the variable hydraulic resistance includes changing the size of the flow restriction.

17. The method of claim 15, wherein the variable hydraulic resistance includes a variable length of the exhaust passage and varying the variable hydraulic resistance includes changing the length of the exhaust passage.

18. The method of claim 10, wherein adjusting the back pressure of the exhaust passage is based on a volume of the liquid form of the metal in the volume of the nozzle.

19. The method of claim 10, wherein the exhaust passage is vented to at least one of atmospheric pressure and a vacuum.

20. The method of claim 19, the metal is directed into the volume through the exhaust passage.

21. The method of claim 10, further comprising tuning the pulses of pressurized gas in a multiple of a natural harmonic of the volume of the nozzle.