A new technique combines 3D printing with laser annealing to produce intricate conductive metallic structures on demand. This method could be used to make flexible electronics, sensors, and small antennas.
A team of Harvard engineers developed the laser-assisted method and published their findings in the Proceedings of the National Academy of Sciences on May 16, 2016. The printer uses ink made of silver nanoparticles, while a precisely programmed laser applies energy to anneal the metal. The biggest challenge the researchers faced was finding the ideal distance between the laser and the nozzle. If the laser gets too close to the nozzle during printing, it will prematurely heat the ink, which then clogs the nozzle with solidified metal. To solve this, they developed a heat transfer model as a function of printing speed, laser intensity, and pulse duration.
This combination allows a user to print structures with both curved and angular shapes, made from wires that are thinner than a human hair. The wires exhibit excellent conductivity and can be printed onto flexible or rigid substrates, so they could be used to create customized electrical devices.
Source: Wyss Institute
