An American start-up company has developed a technology capable of using liquid metal for additive manufacturing.
The Vader Systems process is based on the principles of magnetohydrodynamics. An electrically-pulsed magnetic field permeates liquid metal in an ejection chamber and creates circulating electrical currents that interact with the magnetic field to produce a pressure that squeezes a droplet out of the ejector nozzle.
On their current machine, a strand of aluminium is fed into a heat element that melts it at 750°C. The liquefied metal is then passed to a ceramic tube that forms an ejection chamber and has a submillimeter orifice.
A magnetic coil surrounds the tube and receives a short-lived electrical pulse to create a pressure within the tube that ejects a droplet of liquid metal through the orifice. The ejected drop is projected downward onto a heated platform that manoeuvres to create solid 3D shapes based on layer-by-layer deposition and the coalescence of the droplets.
Chief Technology Officer Zack Vader said they plan to add nozzles to the device to make it faster with a goal of being able to melt and print steel at 1400°C.
He says existing metal printers mostly use a process of laying down powered metal and melting it with a laser or electron beam but that carries the risk of some particles of the powder not melting, creating weakened spots.
The engineering faculty at the University at Buffalo in New York state has assisted the company with advisers. Assistant Professor Chi Zhou, a 3D printing expert, said another advantage of the Vader system is that it is much cheaper than using powdered metal.
“I can see at this stage that it can complement traditional metal printing, but later, maybe ten years later, it can dominate the metal printing market because it can print better quality, cheaper and faster,” said Zhou.
[Products made with the Vader liquid metal printing process. Photo: University at Buffalo/Douglas Levere]