No assembly required: Innovative 3D printing process simplifies the production of multiple materials

Researchers at the University of Missouri have developed a method that allows a single machine to produce complex devices made from multiple materials, including plastics, metals and semiconductors.

The research, recently published in Nature communicationdescribes a novel 3D printing and laser process for producing sensors, circuit boards and even textiles with electronic components made of multiple materials and multiple layers.

It is called “Freeform Multi-material Assembly Process” and promises a revolution in the manufacture of new products.

By printing sensors embedded into a structure, the machine can create things that can sense environmental conditions like temperature and pressure. For other researchers, that could mean having a natural-looking object like a rock or a shell that they can use to measure the movement of seawater. For the public, wearable devices for monitoring blood pressure and other vital signs could be among the possible applications.

“This is the first time this type of process has been used, and it opens up new possibilities,” said Bujingda Zheng, a doctoral student in mechanical engineering 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 done before, and I can do it here at Mizzou.”

One of the main benefits is that innovators can focus on developing new products without having to worry about creating prototypes.

“This opens up the possibility for entirely new markets,” said Jian “Javen” Lin, associate professor of mechanical and aerospace engineering at Mizzou. “It will have far-reaching implications for wearable sensors, customizable robots, medical devices and more.”

Revolutionary techniques

Currently, manufacturing a multilayer structure – such as a circuit board – can be a laborious process involving multiple steps and materials. These processes are costly, time-consuming and can generate waste that harms the environment.

Not only is the new technology better for the planet, it is also inspired by systems found in nature.

“Everything in nature is made 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 to create 3D structures with multifunctional applications, but other new methods have their limitations.”

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In particular, other techniques fall short in terms of the versatility of the material and the precision with which smaller components can be placed within 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 carve shapes and materials, and the third adds additional functional materials to enhance the product’s capabilities. It starts by making a basic structure using regular 3D printing filament, such as polycarbonate, a type of transparent thermoplastic. Then it switches to lasers to convert some parts into a special material called laser-induced graphene and place it exactly where it’s needed. Finally, more materials are added to enhance the functional capabilities of the final product.

“The I-Corps program helps us identify market interests and needs,” Lin said. “Right now, we think it could be of interest to other researchers, but we believe it will ultimately benefit companies as well. It will reduce the manufacturing time for device prototypes by allowing companies to produce prototypes in-house. This technology, which is only available at Mizzou, holds great promise for changing the way products are made and produced.”