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New metal printing technique could make flexible electronics


(Credit: Jingyan Dong, North Carolina State University)
(Credit: Jingyan Dong, North Carolina State University)

A new method for directly printing metal circuits could make flexible electronics a reality.

Researchers at North Carolina State University developed the technique, which can use multiple metals and substrates, and is compatible with existing manufacturing systems.

“Flexible electronics hold promise for use in many fields, but there are significant manufacturing costs involved – which poses a challenge in making them practical for commercial use,” said Jingyan Dong, an associate professor at the university’s department of Industrial Systems and Engineering. “Our approach should reduce cost and offer an efficient means of producing circuits with high resolution, making them viable for integrating into commercial devices.”

Their approach builds on existing electrohydrodynamic printing technology, but using molten metal alloys with low melting points instead of ink. The researchers have demonstrated the technique using three different alloys, printing on four different substrates: glass, paper and two stretchable polymers.

“This is direct printing,” said Dong. “There is no mask, no etching and no moulds, making the process much more straightforward.”

The researchers tested the resilience of their printed circuits, and discovered that conductivity was unaffected even after being bent 1,000 times. They also discovered that the circuits could be healed easily if bent or stretched too far.

“Because of the low melting point, you can simply heat the affected area up to around 70 degrees Celsius and the metal flows back together, repairing the relevant damage,” said Dong.

The researchers also used the technique to create a high-density touch sensor, fitting a 400-pixel array into one square centimeter. “We’ve demonstrated the resilience and functionality of our approach, and we’re open to working with the industry sector to implement the technique in manufacturing wearable sensors or other electronic devices, said Dong.

Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.

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