January 11, 2016

A New Way to Print 3-D Metals and Alloys

A copper lattice structure created with Northwestern Engineering's new 3-D printing process

(January 11, 2016)  New rapid method expands the types of metals, alloys, and architectures that can be additively manufactured

A team of Northwestern Engineers has created a new way to print three-dimensional metallic objects using rust and metal powders.

While current methods rely on vast metal powder beds and expensive lasers or electron beams, Northwestern’s new technique uses liquid inks and common furnaces, resulting in a cheaper, faster, and more uniform process. The Northwestern team also demonstrated that the new method works for an extensive variety of metals, metal mixtures, alloys, and metal oxides and compounds.

“This is exciting because most advanced manufacturing methods being used for metallic printing are limited as far as which metals and alloys can be printed and what types of architecture can be created,” said Ramille Shah, assistant professor of materials science and engineering in the McCormick School of Engineering and of surgery in the Feinberg School of Medicine, who led the study. “Our method greatly expands the architectures and metals we’re able to print, which really opens the door for a lot of different applications.”

Conventional methods for 3-D printing metallic structures are both time and cost intensive. The process takes a very intense energy source, such as a focused laser or electron beam, that moves across a bed of metal powder, defining an object’s architecture in a single layer by fusing powder particles together. New powder is placed on top on the previous layer, and these steps are repeated to create a 3-D object. Any unfused powder is subsequently removed, which prevents certain architectures, such as those that are hollow and enclosed, from being created. This method is also significantly limited by the types of compatible metals and alloys that can be used.