NC State researchers develop 3D printing material, open doors to manufacturing possibilities

Researchers at North Carolina State University developed a new material for 3D printing that could allow users to print metallic objects at room temperature.

A metallic gel for 3D printing was developed, in part, by Ruizhe Xing, a former visiting scholar at N.C. State and an affiliate of Northwestern Polytechnical University and Tianjin University in China. Michael Dickey, a professor of chemical and biomolecular engineering at N.C. State, said the toothpaste-like gel can be used with conventional 3D printing nozzles.

“We’ve done work on liquid metals before, but this was [Xing’s] project,” Dickey said. “He took the copper particles, liquid metal and then some water and mixed it together very aggressively.”

The result is a highly conductive gel that becomes solid once dry, with more favorable mechanical properties than plastics typically used in 3D printing.

“Metals are used for so many different things in our society because they're good conductors of electricity, good conductors of heat and they also have good mechanical properties,” Dickey said.

The gel also allows for four-dimensional printing, with the fourth dimension of time allowing researchers to manipulate the shape of an object during the printing and drying processes.

Copper particles and indium-gallium alloy, a liquid metal, were used to develop the gel, but Dickey said they are exploring more options. “Right now, we’re trying to figure out what the mechanical properties are – how they change over time and how good we can make them,” Dickey said. Using other metals, he added, can change the conductive and mechanical properties of printed objects.

“Metallic Gels for Conductive 3D and 4D Printing,” the paper highlighting Xing’s findings and authored by both Xing and Dickey, was published on July 5 in the academic journal Matter.

While 3D printing has a ways to go, Dickey said this technology can eventually be used in the manufacturing of electronic devices, like cell phones. In the short term, he said the gel can be used to more quickly print metal prototypes.

“My aim is to put this in the hands of users and see what people come up with,” Dickey said.