Physics of metal 3D printing outlined

While the most common method of metal 3D printing is growing exponentially, moving ahead from producing prototypes to manufacturing critical parts will be possible only by reaching a fundamental understanding of the complex physics behind the process, according to a new paper authored by Lawrence Livermore National Laboratory (LLNL) researchers.

The powder bed fusion process, also known as selective laser melting (SLM), requires thin layers of a metal powder to be spread across a build area, where they are fused by a laser or electron beam based on a 3D computer-aided design (CAD) model. The process is repeated until a part is produced, layer-by-layer from the bottom up.

3D printing of metal parts (also known as metal additive manufacturing) for industries such as aerospace and health care is hampered, according to LLNL’s Wayne King, by a lack of confidence in the finished parts. This hurdle, he said, can be overcome by a combination of physics-based modelling and high-performance computing to determine the optimal parameters for building each part.

By modelling the fabrication you can see what is the aggregate behaviour of the part and essentially build in compensations. If there is warping, we can warp the target geometry to arrive at the correct net shape,” said Bob Ferencz, LLNL’s division leader for Computational Engineering, and co-author on the paper. “The benefit of simulations is that you can slow down the process and hopefully that informs you as to mitigations for the mechanisms you see as the cause of the failure.”