Researchers at UC Berkeley have put a new spin on Vat Photopolymerisation. “The Replicator” uses light rays to print liquid resin in a matter of minutes forming complex objects all at once. The new additive manufacturing method also allows for a very high level of smoothness and flexibility in prints.
The team gave it the name Replicator as an homage to the similarly named fictional device from Star Trek. In contrary to ordinary resin 3D printers, it uses a vial with spinning liquid resin and a typical off-the-shelf projector. As the liquid resin spins due to a motor attachment, a computer estimates precisely what series of images will form it into the correct shape.
“Basically, you’ve got an off-the-shelf video projector, which I literally brought in from home, and then you plug it into a laptop and use it to project a series of computed images, while a motor turns a cylinder that has a 3D printing resin in it,” said Hayden Taylor, author of the paper and assistant professor of mechanical engineering at Berkeley. “Obviously there are a lot of subtleties to it — how you formulate the resin, and, above all, how you compute the images that are going to be projected, but the barrier to creating a very simple version of this tool is not that high.”
It also builds the object all at once rather than through layer by layer methods. This idea took inspiration from CT Scanning, which forms a whole object’s scan at once. This gives Berkeley’s Replicator a distinct advantage over the fastest light-based systems, even Carbon’s CLIP.
Light Ray Printer Technology For Mass Customization
The Replicator pulls off another amazing feat in how it can encase certain objects. The researchers conducted a series of tests, one of which involved building a handle for the shaft of a screwdriver. They were able to successfully build the structure around the metal in a matter of minutes. Similar tests had them building models of human jaws and even a replica of the Thinker. These test showed that it can manage some pretty precarious curves and overhangs. Although, this requires the computer to calculate exact patterns forming a series of images, like a movie, with an algorithm.
Taylor believes that the Replicator could be immensely useful for mass customisation for objects like lenses and running shoes.“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,” Taylor said.
The team has already filed a patent for the technology. Even though the light ray printer is still in its early stages, it is beyond promising. Currently, it can only produce objects of about 4 inches in diameter but this is only a prototype. It also has the benefit of not producing any waste.
The resin is a mix of liquid polymers with photosensitive molecules and dissolved oxygen. Light activates photosensitive compound which depletes the oxygen. As a result, only those 3D regions where oxygen is missing can polymers “cross-link” and transform the resin to a solid. Researchers can then recycle the unused resin by heating it up in an oxygen atmosphere.
Featured image courtesy of UC Berkeley.