Dual-light 3D printing technique enables seamless blending of flexible and rigid materials

Impressed by how nature blends toughness and adaptability, such because the inflexible construction of bone surrounded by pliable cartilage, all with elegant and exact geometric properties, researchers at The College of Texas at Austin have developed a quick, exact new 3D printing technique that seamlessly merges smooth and laborious properties right into a single object utilizing totally different colours of sunshine.

This advance might pave the way in which for next-generation prosthetics, versatile medical gadgets and stretchable electronics that transfer naturally with the physique, very similar to a human joint or ligament. The method is described in a paper revealed at this time in Nature Supplies.

“What actually motivated me and my analysis group is supplies in nature,” stated Zak Web page, an assistant professor of chemistry at UT Austin and corresponding writer. “Nature does this in an natural approach, combining laborious and smooth supplies with out failure on the interface. We wished to copy that.”

A related paper revealed Could 29 in ACS Central Science from Web page and different authors, describes adjoining work, which the journal’s editors praised in a “First Reactions” commentary, saying the work represents “the way forward for 3D printing” and showcases “how gentle─not merely as a software for curing resin, however as a finely tuned sculptor─can drive the subsequent technology of additive manufacturing.”

“This strategy might make additive manufacturing extra aggressive for higher-volume manufacturing in contrast with conventional processes like injection molding. Simply as necessary, it opens up new design potentialities,” stated Keldy Mason, lead writer of the latter examine and a graduate pupil in Web page’s lab. “This offers engineers, designers and makers extra freedom to create.”

One of many greatest challenges in creating objects with vastly totally different bodily properties is that supplies are inclined to fail on the interface, or the purpose they arrive involved. Take into consideration how the rubber sole of a working shoe will separate over time from the softer mesh fabric above it.

The brand new 3D printing technique makes use of a custom-designed liquid resin and a dual-light printing system that prompts totally different chemical reactions relying on the colour of sunshine used. By shining violet gentle, the resin cures right into a stretchy, rubber-like materials. However in areas hit with higher-energy ultraviolet gentle, it turns into inflexible and powerful. The result’s an object with distinct zones of softness and hardness crafted in a single print.

“We inbuilt a molecule with each reactive teams so our two solidification reactions might ‘discuss to one another’ on the interface,” Web page stated. “That offers us a a lot stronger connection between the smooth and laborious components, and there generally is a gradual transition if we would like.”

The crew demonstrated the system by printing a small however practical knee joint with versatile ligaments and inflexible bones that transfer collectively easily. Additionally they created a prototype stretchable digital machine with a gold wire mounted on a strip that might bend and stretch in components, however with a extra inflexible part to forestall the circuit from breaking.

“Actually, what shocked me most was how effectively it labored on the primary attempt. That nearly by no means occurs with 3D printing resins,” Web page stated. “We have been additionally shocked by how totally different the properties have been. The smooth components stretched like a rubber band and bounced again. The laborious components have been as sturdy as plastics utilized in shopper merchandise.”

The method additionally works quicker and with higher decision than earlier approaches. And since the printer setup is comparatively easy and inexpensive, the expertise might develop into accessible to researchers, hospitals and educators.

“It could possibly be used to prototype surgical fashions, wearable sensors and even smooth robots,” Web page stated. “There’s a lot potential right here.”