A new 3D printer can create metal structures in mid-air with no need for supports.
The device, which has yet to be named, was developed by Harvard University's Wyss Institute for Biologically Inspired Engineering and the John A. Paulson School of Engineering and Applied Sciences (SEAS).
"I am truly excited by this latest advance from our lab, which allows one to 3D print and anneal flexible metal electrodes and complex architectures 'on-the-fly,'" lead researcher and Wyss Core Faculty member Jennifer Lewis said in a statement.
The printer uses ink composed of silver nanoparticles, Engadget reported.
A laser then heats the material and hardens it as it comes out of a nozzle, which is combined with a rotary print stage to allow freeform curvature.
Mark Skylar-Scott, one of the study's authors and a Wyss Institute postdoctoral fellow, said the most difficult part was perfecting the technique.
"If the laser gets too close to the nozzle during printing, heat is conducted upstream which clogs the nozzle with solidified ink," Skylar-Scott said. "To address this, we devised a heat transfer model to account for temperature distribution along a given silver wire pattern, allowing us to modulate the printing speed and distance between the nozzle and laser to elegantly control the laser annealing process 'on-the-fly.'"
The result is that the technique can produce sweeping curves and spirals, as well as sharp angular turns and directional changes.
The method, which can be seen demonstrated to make some 3D wire butterflies, could also be used to create flexible and customized materials for electronic and medical devices.
"This sophisticated use of laser technology to enhance 3D printing capabilities not only inspires new kinds of products, it moves the frontier of solid free-form fabrication into an exciting new realm, demonstrating once again that previously-accepted design limitations can be overcome by innovation," explained Wyss Institute director Donald Ingber.
The research was published on Monday in the Proceedings of the National Academy of Sciences.
Here's the printer in action: