The vast majority of 3D printing today is done with plastics. There are, however, a number of more specialized materials that can be 3D-printed, including food, concrete, and even biological tissue. Metal is also possible to 3D print, but that’s difficult and expensive. The most popular technique is SLS (Selective Laser Sintering), where powdered metal is melted with a laser. That works for large objects, but a new technique makes it possible to accurately 3D print strong metals at very small scales.
This development comes from a team of researchers at the Swiss Federal Institute of Technology in Zurich, and utilizes a completely new process for 3D printing metals. At very small scales, the most practical method of 3D printing metals has been to suspend nanoparticles in a solution, which is then deposited with a nozzle onto the build plate. That is then heated and dried to form a solid. But, despite being made of metal, the resulting solid structure has far poorer mechanical and electrical performance than the same metal manufactured by traditional means.
This new method works by depositing electrically-charged metal ions onto the build plate. Those metal ions are carried by electrical forces from a sacrificial anode in the 3D printer’s nozzle to the build plate. That process offers a number of advantages. It can be done with any metal, it’s highly-accurate, the resulting structure has better mechanical and electrical properties, and metals can be alternated during the printing process to produce complex objects. As the researchers have demonstrated, they can print the metals at resolutions of 250 nanometers (billionths of a meter) while still retaining the desirable properties of the metal.