Finite Element Analysis of Residual Stresses and Deformations in Direct Metal SLS Process

Direct metal SLS processes use a high power laser beam to selectively fuse fully metallic powder to directly produce functional metal components or tooling. As a thermal dynamic process, it inevitably causes thermal stresses, stress-induced deformations and cracking. Understanding these is very important in controlling residual stresses and stress-induced deformations. In this research, the residual stresses and deformations in direct laser sintering of stainless steel is investigated by an integrated thermal and mechanical model. Temperature-dependent material properties are taken into account in both models. Using a commercial finite element software, with sintered geometry and temperatures imported from a thermal model, the residual stresses and deformations of direct SLS of stainless steel are predicted. In the long term this will make it possible to achieve minimum residual stresses and deformations by controlling the SLS process parameters, material properties and other relevant parameters.