Scientists have invented a 3D printer that uses light to transform gloopy liquids into solid objects.


Nicknamed the ‘replicator’ after the Star Trek machine that makes things on demand, the device can create objects that are smoother, bendier and more complex than those made with standard 3D printers.

The printer – developed by researchers at the University of California, Berkeley, and the Lawrence Livermore National Laboratory – works by shining patterns of light onto a rotating vial of syrupy liquid. As the liquid reacts with the light, it crystallises into a solid, creating an object in under two minutes.

So far, the printer has made a replica jawbone, toy planes and bridges, as well as a miniature version of Rodin’s famous sculpture The Thinker. It can currently print objects up to 10cm in diameter, but the researchers are thinking bigger.

“I think this is a route to being able to mass-customize objects even more, whether they are prosthetics or running shoes,” said project leader Prof Hayden Taylor.

The secret of the technique is to create patterns of light which solidify the liquid in the desired places. First, researchers make a 3D computer model of the object, which an algorithm then converts into a moving sequence of 2D images – essentially a movie – that shows the object from every angle.

This movie is then beamed onto a special resin which is sensitive to light. As the resin rotates, the points which receive more light become solid. Once the process is complete, the remaining liquid is poured away to reveal the fully-formed sculpture.

Conventional 3D printers build objects up one layer at a time. This typically gives a jagged ‘stair-step’ effect along the edges, and also makes it difficult to create flexible objects, as bendy materials can become deformed during the printing process. The new printer gets around that problem by creating the entire shape in one go. It’s also able to cope with tricky features such as overhangs and disconnected parts.

Dental implants, jewellery and architectural models are just a few potential uses for this technology. “This is the first case where we don’t need to build up custom 3D parts layer by layer,” said Brett Kelly, co-first author on the paper. “It makes 3D printing truly three-dimensional.”


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