Researchers at the National University of Singapore developed a technique called CHARM3D, which forms metal structures not by pushing material out, but by pulling molten metal into shape using surface tension. The process uses Field’s metal, a low-melting-point alloy composed of bismuth, indium, and tin that liquefies at roughly 62°C. Because the metal melts at such a low temperature, it can be manipulated in liquid form without the extreme heat typically required for metal additive manufacturing. Instead of extruding a filament, the system forms a droplet of molten alloy at the nozzle. As the print head moves away, surface tension pulls the metal into a thin continuous filament, creating a suspended microwire that rapidly solidifies as it cools in air. This tension-driven mechanism enables something unusual in additive manufacturing: free-standing conductive structures printed directly in space. Researchers demonstrated several geometries, including: • Helical coils and springs ...