Magnetohydrodynamic deposition of metal in manufacturing

Patent metadata

Field	Value
Publication number	US-10201854-B2
Application number	US-201715451260-A
Country	US
Kind code	B2
Filing date	Mar 6, 2017
Priority date	Mar 3, 2016
Publication date	Feb 12, 2019
Grant date	Feb 12, 2019

Abstract

Devices, systems, and methods are directed to applying magnetohydrodynamic forces to liquid metal to eject liquid metal along a controlled pattern, such as a controlled three-dimensional pattern as part of additive manufacturing of an object. The magnetohydrodynamic force can be pulsed to eject droplets of the liquid metal to provide control over accuracy of the object being fabricated. The pulsations can be applied in fluid chambers having high resonance frequencies such that droplet ejection can be effectively controlled over a wide range of frequencies, including high frequencies suitable for liquid metal ejection at rates suitable for commercially viable three-dimensional fabrication.

First claim

What is claimed is:

1. An additive manufacturing system, the additive manufacturing system comprising:
a nozzle including a housing, one or more magnets, and electrodes, the nozzle defining a fluid chamber having an inlet region and a discharge region, the one or more magnets directing a magnetic field through the housing, and the electrodes defining at least a portion of a firing chamber in the fluid chamber between the inlet region and the discharge region, wherein electric current is conductible from the electrodes such that the electric current intersects the magnetic field in the firing chamber at a point substantially adjacent to a discharge orifice of the discharge region;
a robotic system mechanically coupled to the nozzle;
an electrical power source in electrical communication with the electrodes; and
a controller in electrical communication with the robotic system and the electrical power source, the controller configured to
move the robotic system to position the discharge region of the nozzle in a controlled three-dimensional pattern, and
based on the position of the discharge region along the controlled three-dimensional pattern, to actuate the electrical power source to deliver pulsed current to the electrodes to eject liquid metal from the discharge region to form a three-dimensional object, wherein a frequency of the pulsed current is less than about 5 kHz at a maximum speed of movement of the discharge region, and the frequency of the pulsed current is based on speed of movement of the nozzle.

2. The additive manufacturing system of claim 1 , wherein the frequency of the pulsed current is further based on one or more features of the three-dimensional pattern.

3. An additive manufacturing system, the additive manufacturing system comprising:
a nozzle including a housing, one or more magnets, and electrodes, the nozzle defining a fluid chamber having an inlet region and a discharge region, the one or more magnets directing a magnetic field through the housing, and the electrodes defining at least a portion of a firing chamber in the fluid chamber between the inlet region and the discharge region, wherein electric current is conductible from the electrodes such that the electric current intersects the magnetic field in the firing chamber at a point substantially adjacent to a discharge orifice of the discharge region;
a robotic system mechanically coupled to the nozzle;
an electrical power source in electrical communication with the electrodes; and
a controller in electrical communication with the robotic system and the electrical power source, the controller configured to
move the robotic system to position the discharge region of the nozzle in a controlled three-dimensional pattern, and
based on the position of the discharge region along the controlled three-dimensional pattern, actuate the electrical power source to deliver pulsed current to the electrodes to eject liquid metal from the discharge region to form a three-dimensional object, wherein the pulsed current has a frequency based on speed of movement of the nozzle.

4. The additive manufacturing system of claim 3 , the frequency of the pulsed current is further based on one or more features of the controlled three-dimensional pattern.

5. The additive manufacturing system of claim 4 , wherein the frequency of the pulsed current is based on curvature of a perimeter of the controlled three-dimensional pattern at the position of the discharge region along the controlled three-dimensional pattern.

6. The additive manufacturing system of claim 3 , wherein the frequency of the pulsed current decreases based on a decrease in speed of movement of the nozzle along the controlled three-dimensional pattern.

7. The additive manufacturing system of claim 3 , wherein the controller is further configured to control a velocity of the liquid metal ejected from the discharge region based on the position of the discharge region along the controlled three-dimensional pattern.

8. The additive manufacturing system of claim 7 , wherein the controller is configured to control the velocity of the liquid metal based on controlling one or more of magnitude and duration of the pulsed current.

9. The additive manufacturing system of claim 7 , wherein the controller is configured to reduce the velocity of the liquid metal ejected from the discharge region along a portion of the controlled three-dimensional pattern corresponding to an interface between a part and a support structure of the three-dimensional object.

Assignees

• Desktop Metal Inc

Inventors

• Sachs Emanuel Michael
• Gibson Mark Gardner
• Hoisington Paul A
• Fontana Richard Remo

Classifications

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title

• B33Y30/00

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

• B22F3/115 Primary

  by spraying molten metal, i.e. spray sintering, spray casting · CPC title

• B05B5/025

  Discharge apparatus, e.g. electrostatic spray guns · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title