Robotic hand complete with bones, ligaments, and tendons

This achievement, a collaborative effort by ETH Zurich and a US-based startup, represents a significant leap in the capabilities of 3D printing technology.

3D printing technology has been evolving at a rapid pace, expanding the range of materials that can be used. While earlier limited to fast-curing plastics, the technology has now been adapted for slow-curing plastics, which offer enhanced elasticity, durability, and robustness. This breakthrough in material usage marks a pivotal shift from the traditional constraints of 3D printing.

The innovation behind this development lies in a new technology formulated by researchers at ETH Zurich in collaboration with a US startup. This advancement allows the printing of complex, durable robotic structures from a variety of high-grade materials in a single process. Importantly, the technology enables the easy combination of soft, elastic, and rigid materials, allowing for the creation of intricate structures and parts with cavities.

A notable application of this technology is evident in the creation of a robotic hand at ETH Zurich. “We wouldn’t have been able to make this hand with the fast-curing polyacrylates we’ve been using in 3D printing so far,” says Thomas Buchner, a doctoral student and the first author of the study. The team used slow-curing thiolene polymers, known for their excellent elastic properties and quick return to their original state after bending, making them ideal for producing the elastic ligaments of the robotic hand.

Robert Katzschmann, robotics professor at ETH Zurich, highlights the benefits of soft robots: “Robots made of soft materials, such as the hand we developed, have advantages over conventional robots made of metal. Because they’re soft, there is less risk of injury when they work with humans, and they are better suited to handling fragile goods.”

The new 3D printing technique deviates from the traditional layer-by-layer method that involves immediate curing by UV lamps and scraping off surface irregularities. The novel approach uses a 3D laser scanner to check each printed layer for irregularities. “A feedback mechanism compensates for these irregularities when printing the next layer by calculating any necessary adjustments to the amount of material to be printed in real time and with pinpoint accuracy,” explains Wojciech Matusik, a professor at MIT and co-author of the study.

With the successful demonstration of this technology, Katzschmann’s group at ETH Zurich plans to explore more sophisticated structures and applications. Concurrently, Inkbit, the MIT spin-off responsible for developing the new printing technology, aims to commercialise this advancement by offering 3D printing services and selling the new printers.

This collaborative effort, documented in the journal Nature, opens new horizons in robotics and prosthetics, potentially transforming the way robotic aids are manufactured and used, especially in medical and therapeutic applications.