UC Berkeley scientists have developed a new 3D printer that transforms liquid polymers into complex solid objects using only light.
Called the ‘Replicator,’ the Berkeley invention is capable of creating objects that are smoother, more flexible and more complex than what is possible with traditional 3D printers.
According to the researchers, it can also encase an already existing object with new materials – like adding a handle to a metal screwdriver shaft – which current printers struggle to do.
“I think this is a route to being able to mass-customize objects even more, whether they are prosthetics or running shoes,” said senior author of the paper and assistant professor Hayden Taylor.
“The fact that you could take a metallic component or something from another manufacturing process and add on customizable geometry, I think that may change the way products are designed,” he intones.
The new printer draws its inspiration from computed tomography (CT) scans that help doctors locate tumors and fractures within the body.
CT scans project X-rays or other types of electromagnetic radiation into the body from all different angles. Analyzing the patterns of transmitted energy reveals the geometry of the object.
“Essentially we reversed that principle,” said Taylor. “We are trying to create an object rather than measure an object, but actually a lot of the underlying theory that enables us to do this can be translated from the theory that underlies computed tomography.”
The 3D printing resin is composed of liquid polymers mixed with photosensitive molecules and dissolved oxygen.
According to the researchers, light activates the photosensitive compound which depletes the oxygen.
Only in those 3D regions where all the oxygen has been used up do the polymers form the ‘cross-links’ that transform the resin from a liquid to a solid.
The unused resin can then be recycled by heating it up in an oxygen atmosphere, asserts Taylor.
“Our technique generates almost no material waste and the uncured material is 100 percent reusable,” says Hossein Heidari, a graduate student and the study’s co-first author. “This is another advantage that comes with support-free 3D printing.”
Content, video and image: UC Berkeley/Hayden Taylor