Show-Me State Times

University of Missouri researchers have developed a method to create complex devices with multiple materials, including plastics, metals, and semiconductors, using a single machine. The research, recently published in Nature Communications, introduces a novel 3D printing and laser process for manufacturing multi-material, multi-layered sensors, circuit boards, and textiles with electronic components.

The technique is called the Freeform Multi-material Assembly Process and has the potential to revolutionize product fabrication. By embedding sensors within structures, the machine can produce items capable of sensing environmental conditions such as temperature and pressure. This innovation could lead to applications ranging from natural-looking objects that measure ocean water movement to wearable devices monitoring vital signs.

“This is the first time this type of process has been used, and it’s unlocking new possibilities,” said Bujingda Zheng, a doctoral student in mechanical engineering at Mizzou and the 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 getting to do that here at Mizzou.”

One significant advantage is that innovators can focus on designing new products without worrying about prototyping complexities. “This opens the possibility for entirely new markets,” said Jian “Javen” Lin, an associate professor of mechanical and aerospace engineering at Mizzou. “It will have broad impacts on wearable sensors, customizable robots, medical devices and more.”

Currently, manufacturing multi-layered structures like printed circuit boards involves multiple steps and materials. These processes are costly, time-consuming, and generate waste harmful to the environment. The new technique not only addresses these issues but is also inspired by systems found in nature.

“Everything in nature consists of structural and functional materials,” Zheng explained. “For example, electrical eels have bones and muscles that enable 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 multi-functional applications.”

The Mizzou team’s method uses special techniques to overcome limitations in material versatility and precision placement of smaller components within larger 3D structures. Their machine features three different nozzles: one adds ink-like material; another uses a laser for shaping; and the third adds additional functional materials. The process begins with regular 3D printing filament like polycarbonate before switching to a laser that converts parts into laser-induced graphene precisely where needed.

This work is funded by the National Science Foundation (NSF) Advanced Manufacturing program with additional support from the NSF I-CorpsTM program for exploring commercialization opportunities.

“The I-Corps program is helping us identify market interests and needs,” Lin noted. “Currently, we believe it would be of interest to other researchers but ultimately benefit businesses by shortening fabrication time for device prototyping through in-house production.”