New 3D printing technique advances soft robotics

Researchers at the Swiss Federal Institute of Technology in Zurich (ETH) have for the first time succeeded in printing, in one go, a robotic hand with bones, ligaments, tendons and embedded sensor cavities made of different polymers, according to a statement. It required no assembly: as a video from the ETH shows, the printed hand was actuated and was immediately fully functional. The same applies to walking robots, which opens up new possibilities in the field of soft robotics.

The innovation is based on slow-curing plastics, which have better elastic properties and are more durable and robust than the fast-curing plastics previously used in 3D printing. “We’re now using slow-​curing thiolene polymers,” explained ETH robotics professor Robert Katzschmann in the statement. “These have very good elastic properties and return to their original state much faster after bending than polyacrylates.”

The new process also handles unevenness in a different way. Whereas previously any unevenness was scraped off after each curing step, a 3D laser scanner now immediately checks each printed layer for possible unevenness and takes it into account when printing the next layer.

The company Inkbit, a spin-off from Massachusetts Institute of Technology (MIT), designed the new printing technology. The ETH researchers developed several robotics applications and helped to optimize the printing technology for the use of slow-curing polymers. Together, the researchers published their innovative technology and application in the journal "Nature". ce/mm