Finding the flow creates a new way to 3D-print metal

Researchers at Lawrence Livermore National Laboratory (LLNL) have developed a new way of 3D-printing metals that could improve on existing, laser-on-powder based methods.It relies on using semi-solid metals that are solid at rest, but can flow when force is applied, making it possible to move through the nozzle of a printer.

  Direct metal writing uses semi-solid heated metals forced through a 3D printer nozzle

Direct metal writing uses semi-solid heated metals forced through a 3D printer nozzle (Credit: Lawrence Livermore National Lab)

The team, along with collaborators from Worchester Polytechnic Institute, call the new approach “direct metal writing.” Rather than starting with a metal powder as in currently popular 3D-printing techniques like selective laser melting (SLM), a block of metal engineered to be shear thinning is heated until it becomes semi-solid.

Being shear thinning means that it acts a little bit like paste when heated – solid metal particles are surrounded by a liquid metal and the solids clump up when at rest, but when force is applied, those solids break apart and flow along with the liquid metal. These properties allow the metal to flow through a nozzle. The printed object then hardens as it cools, leaving fewer potential defects than with other flash melting techniques like SLM, according to the researchers.

>> Read more by Eric Mack, New Atlas, March 31, 2017