Lasers and metal were part of 3D printing for decades before the machines became affordable for personal use. But researchers at Harvard are demonstrating a new technique by which 3D metal structures can be printed in midair, without the need for anything supporting them. If you're not familiar with the process, 3D printers slowly build up objects layer by layer, relying on the previous layers to support all of the new ones. Objects with parts that hang in midair can typically only be created by adding temporary support materials during the printing process that later have to be removed — an additional time-consuming step, and a waste of materials.
What the researchers at Harvard's Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences have come up with is a special ink made of silver nanoparticles that can be hardened using using a precisely focused laser as it's being extruded from a nozzle. It's a technique similar to what 3D printing pens use, except that instead of plastic filament that immediately hardens as it cools, Harvard's printer creates objects from durable metal.
The custom 3D printer's nozzle is free to move in all directions as it's extruding material, and is precise enough to create conductive wires less than the width of a human hair. The machine has the potential to improve how electronics are manufactured, but also how they're designed given it seemingly has few constraints when it comes to how a circuit is laid out.
It could also revolutionise 3D printing in general, as the techniques developed here could be adapted to work with plastic filament as well, hardening the material as soon as it leaves the extrusion nozzle, allowing more freeform creations to be rapidly created. And let's not even begin to imagine what this technology could do for the cake decorating industry.