No Assembly Required: Innovative 3D printing method streamlines multi-material production

Researchers at the University of Missouri have developed a way to create complex devices using multiple materials, including plastics, metals and semiconductors, all with a single machine.

The research, which was recently published in Nature communicationoutlines a new 3D printing and laser process to produce multi-material, multi-layer sensors, printed circuit boards and even textiles with electronic components.

It’s called the Freeform Multi-material Assembly Process and promises to revolutionize the manufacturing of new products.

By printing sensors embedded in a structure, the machine can create things that can sense environmental conditions, including temperature and pressure. For other researchers, this could mean having a natural-looking object, such as a rock or seashell, that could measure the movement of ocean water. For the public, applications may include wearable devices that monitor blood pressure and other vital signs.

“This is the first time this kind of process has been used and it opens up new possibilities,” said Bujingda Zheng, a mechanical engineering doctoral student at Mizzou and lead author of the study. “I’m excited about the design. I’ve always wanted to do something that no one has ever done before, and I’m going to do that here at Mizzou.”

One of the key benefits is that innovators can focus on designing new products without worrying about prototyping them.

“This opens up the possibility of entirely new markets,” said Jian “Javen” Lin, associate professor of mechanical and aerospace engineering at Mizzou. “It will have a broad impact on wearable sensors, adaptive robots, medical devices and more.”

Revolutionary techniques

Currently, manufacturing a multi-layer structure such as a printed circuit board can be a cumbersome process involving multiple steps and materials. These processes are expensive, time-consuming and can generate waste that is harmful to the environment.

The new technology is not only better for the planet, but is also inspired by systems from nature.

“Everything in nature is made up of structural and functional materials,” Zheng said. ‘Electric eels, for example, have bones and muscles that allow them to move. They also have specialized cells that can discharge up to 500 volts to deter predators. These biological observations have inspired researchers to develop new methods for fabricating 3D structures with multifunctional applications, but other emerging methods have limitations.”

Other techniques fall particularly short when it comes to how versatile the material can be and how accurately smaller components can be placed into larger 3D structures.

The Mizzou team’s method uses special techniques to solve these problems. Team members built a machine with three different nozzles: one adds ink-like material, another uses a laser to cut shapes and materials, and the third adds additional functional materials to enhance the product’s capabilities. It starts by creating a basic structure with regular 3D printing filament, such as polycarbonate, a type of transparent thermoplastic material. It then switches to laser to convert some parts into a special material called laser-induced graphene, which gets it exactly where it’s needed. Finally, more materials are added to improve the functional capabilities of the final product.

“The I-Corps program helps us identify market interests and needs,” Lin said. “Currently, we think this would be of interest to other researchers, but we think it will ultimately benefit companies. It will reduce the manufacturing time for prototyping devices by allowing companies to prototype in-house. This technology, which available only at Mizzou holds tremendous promise for transforming the way products are manufactured and manufactured.”