This new 3D printing technique puts electronics into plastics 

Researchers have embedded high-performance electrical circuits inside plastics they created with 3D printing.

The plastics could lead to smaller and versatile drones and better-performing small satellites, biomedical implants, and smart structures.

The researchers used pulses of high-energy light to fuse tiny silver wires, resulting in circuits that conduct 10 times more electricity than the state of the art, according to their study in the journal Additive Manufacturing. By increasing conductivity 10-fold, the engineers can reduce energy use, extend the life of devices, and increase their performance.

“Our innovation shows considerable promise for developing an integrated unit—using 3D printing and intense pulses of light to fuse silver nanoparticles—for electronics,” says senior author Rajiv Malhotra, an assistant professor in the mechanical and aerospace engineering department in the School of Engineering at Rutgers University–New Brunswick.

Embedding electrical interconnections inside 3D-printed structures made of polymers, or plastics, can create new paradigms for devices that are smaller and more energy-efficient. Such devices could include CubeSats (small satellites), drones, transmitters, light and motion sensors, and Global Positioning Systems. Such interconnections could also be useful in antennas, pressure sensors, electrical coils, and electrical grids for electromagnetic shielding.

The engineers used high-tech “intense pulsed light sintering”—featuring high-energy light from a xenon lamp—to fuse long thin rods of silver called nanowires. Nanomaterials are measured in nanometers (a nanometer is a millionth of a millimeter—about 100,000 times thinner than a human hair). Devices such as solar cells, displays, and radio-frequency identification (RFID) tags already use fused silver nanomaterials to conduct electricity.

The next steps include making fully 3D internal circuits, enhancing their conductivity, and creating flexible internal circuits inside flexible 3D structures, Malhotra says.