Metal Droplet Jetting - Magnetohydrodynamic Liquid Metal Droplet jetting - A Low-Cost Additive Manufacturing Process

1995

Patent US5598200A   United States

Method and apparatus for producing a discrete droplet of high temperature liquid

Abstract

A method and an apparatus (10) eject on demand a discrete droplet (12) of liquid at a high temperature along a predetermined trajectory (18) by transferring a physical impulse from a low temperature environment to a high temperature environment. The ejector apparatus includes a vessel (26) having an interior (24) that contains a high-temperature liquid (14), such as liquid metal, Al, Zn or Sn. The interior includes an inlet end (30) that receives a thermally insulative impulse transmitting device (22) and a feed supply (34) of the droplet material, and a discharge region (56) having an orifice (16) through which the discrete droplets are ejected. An inert gas is feed through the inlet end and into the vessel to create an overpressure over the liquid so that as the overpressure is increased the droplet size is increased. A heater (70) heats the material contained within the interior. An impulse generator (20) is connected and imparts a physical impulse to the impulse transmitting device to produce an ejection pressure at the orifice to eject a discrete droplet of the high-temperature liquid. The impulse generator including a pulse generator electrically connected to a pulse amplifier that is electrically connected to an acoustic device, such as a loudspeaker.

Inventor  David W. Gore

Application US08/378,713 events 

1995-01-26

Application filed by Individual

1995-01-26

Priority to US08/378,713

1996-01-22

Priority to EP96904509A

1996-01-22

Priority to PCT/US1996/001132

1997-01-28

Application granted

1997-01-28

Publication of US5598200A

2015-01-26

Anticipated expiration

Status

Expired - Fee Related

https://patents.google.com/patent/US5598200A/en

2014

US20150273577A1

United States

Conductive Liquid Three Dimensional Printer

Abstract

A printer that produces objects from liquid conductive material is disclosed. In one embodiment, the printhead has a chamber for containing liquid conductive material surrounded by an electromagnetic coil. A DC pulse is applied to the electromagnetic coil, resulting in a radially-inward force on the liquid conductive material. The force on the liquid conductive material in the chamber results in a drop being expelled from an orifice. In response to a series of pulses, a series of drops fall onto a platform in a programmed pattern, resulting in the formation of an object.

nventorScott VaderZachary VaderCurrent Assignee Alloy Acquisition Corp LLC

Worldwide applications

2014  US 2017  US

Application US14/228,681 events 

2014-03-28

Application filed by Individual

2014-03-28

Priority to US14/228,681

2015-10-01

Publication of US20150273577A1

2017-03-13

Priority to US15/457,586

2017-04-11

Application granted

2017-04-11

Publication of US9616494B2

2022-02-04

Assigned to ALLOY ACQUISITION CORP, LLC

Status

Expired - Fee Related

2034-11-23

Adjusted expiration

https://patents.google.com/patent/US20150273577A1/en

2019

Back in 2013 father and son Scott and Zach Vader developed an alternative additive manufacturing process, Magnetohydrodynamic (MHD) printing. They applied for patent in 2014. Acquired by Xerox in February 2019, Vader Systems’ technology uses wire feedstock in lieu of powder. Gravity feeds the molten metal from a tiny crucible into a nozzle and jets individual molten metal droplets on demand, creating dense metallic parts.

Low-Cost Material 

The wire feedstock used in MHD can be as little as one fifth the cost of similar metal in powder form, making the process more cost effective and accessible for a variety of applications and industries.  MHD also allows for greater control and geometric freedom in the production of parts by customising drop size, placement and spacing.

Using its drop by drop method, MHD can produce engineered lattice structures without the need for support materials – by overlapping the metal droplets to create an in-built diagonal support system. This helps create more complex structures without the need to remove supports in post production, helping to save time and costs. Geometric complexity can be achieved more easily and more cost effectively than traditional methods like die casting and even PBF, making MHD ideal for lightweighting in industries like automotive and aerospace.

MHD is currently is most suitable for aluminium and zinc alloys, as well as for aluminium alloys that are traditionally considered ‘unweldable’. 

Research of Denis Comier - Earl W. Brinkman Professor of Industrial and Systems Engineering at Rochester Institute of Technology 

Prof. Comier experimented with using MHD to print aluminium circuit board patterns onto flexible plastic substrates and, he reported that worked quite well. Drop off in conductivity was not there and there is good adhesion to the plastic. The  feedstock is two orders of magnitude less expensive than silver nanoparticle inks, which could be a real game-changer in advancing printed electronics from research into industrial applications.

https://www.theengineer.co.uk/content/opinion/how-metal-droplet-jetting-could-make-metal-printing-viable

Molten metal jetting for additive manufacturing

Abstract

In molten metal jetting, where droplets of metal are jetted to 3D print a part, each layer may be traversed each successive layer with a normalizing grinding wheel or other leveling device such as a layer to level each successive layer, and/or the melt reservoir or printing chamber may be filled with an anoxic gas mix to prevent oxidation.

Application US16/427,448 events 

2019-05-31   Application filed by Markforged Inc

2019-05-31   Assigned to MARKFORGED, INC.

2019-12-12    Publication of US20190375003A1

2020-03-17    Publication of US10589352B2

2024-12-04  Assigned to CONTINUOUS COMPOSITES INC.

https://patents.google.com/patent/US10589352B2/en

2021

Phd Thesis, 2021

Direct Writing of Printed Electronics through Molten Metal Jetting

Author

Manoj Meda

Advisor

Denis R. Cormier

Advisor/Committee Member

Marcos Esterman

Advisor/Committee Member

Rui Li

Recommended Citation

Meda, Manoj, "Direct Writing of Printed Electronics through Molten Metal Jetting" (2021). Thesis. Rochester Institute of Technology. Accessed from

https://repository.rit.edu/theses/10923

Magnetohydrodynamic liquid metal droplet jetting of highly conductive electronic traces

Manoj Meda, Paarth Mehta, Chaitanya Mahajan, Bruce Kahn and Denis Cormier∗

Rochester Institute of Technology, Rochester, NY, United States of America

Flex. Print. Electron. 6 (2021) 035002 

https://iopscience.iop.org/article/10.1088/2058-8585/ac0fee/pdf

2026

Supplier offering Liquid Metal Jetting Parts

https://www.m2nxt.com/liquid-metal-jetting

The potential advantages of metal additive manufacturing (AM) envisaged include the elimination of tooling costs, the possibility of on-demand manufacturing close to the point of need, near net shape production that reduces material consumption, and the ability to produce complex geometries that are impossible to make with conventional processes. But  much of this potential has not been realized. The majority of production applications for metal AM have been limited to low volume, high-value parts for the aerospace and biomedical industries. Outside of those industries, it is often said that if a part can be CNC machined, then it will be faster and less expensive to CNC machine it than to make it via metal AM. The reasons for this are: Production grade metal AM machines often cost several multiples of the price of one CNC milling machine. Likewise, metal powder can be ten times or more expensive than bar stock used in CNC machining. Per-part print times can run hours to days, versus minutes to hours for CNC machining. 

Laser Powder Bed Fusion (L-PBF) is the dominant metal AM process at the present time. l-PBF processes are well understood and are exceptionally well suited for making relatively small parts with intricate detail. The high cost of l-PBF machines and metal powder, coupled with low production speeds and environmental health and safety concerns explain why l-PBF has struggled to gain significant traction beyond the aerospace and biomedical industries. Binder jetting is likewise well suited for production of small metal parts with intricate detail. The equipment costs of binder jetting machines coupled with production-scale debinding and sintering furnaces are similar to those of l-PBF machines. Binder jetting likewise has similar concerns with the cost of metal powders and infrastructure needed to safely handle those powders.

Wire-feed Directed-Energy-Deposition (DED) methods (e.g., Laser Wire DED, Wire Arc AM and Electron Beam Wire AM) typically have lower per-part material costs than powder-based metal AM processes. The relatively high material deposition rates and robot motion stages make them well suited to produce very large parts. The tradeoff for high deposition rate with these processes is coarse feature resolution.

Molten Metal Jetting (MMJ) is an emerging metal AM process that uses on-demand ejection of molten metal droplets from a nozzle to produce metallic parts. There are multiple approaches to generating droplet ejection pressure pulses in MMJ printheads. Pressure may be generated via magnetohydrodynamic (MHD) , electrohydrodynamic (EHD), pneumatic, or vibrating piston jetting methods. Regardless of the droplet actuation method, each of these MMJ variants melts metal in a crucible prior to deposition. This means that any form of feedstock material may be used, including wire, rod, or even grain produced from ingots. For systems that use ingot as the feedstock material, the raw material cost of near net shape MMJ is even lower than that of CNC machined raw material. That represents a very important step towards tilting the scales from CNC machining with large material waste towards use of metal AM.

MMJ has been used to jet alloys of tin, alumimum, and Copper. . Reported droplet diameters range from as small as 50 µm  to as large as 700 μm. Current state of the art commercially available systems claim deposition rates up to 199  using a drop size of 700 µm. There is obviously a tradeoff between deposition rate and feature resolution when selecting the diameter of the nozzle that droplets are jetted from. To increase deposition rates without sacrificing feature resolution, an array of individually addressable nozzles can be used. 

https://www.sciencedirect.com/science/article/pii/S2772369026000046