Process Simulation for Selective Laser Melting

Selective Laser Melting (SLM) is an Additive Manufacturing (AM) process where a powder bed is locally melted. Layer by layer, complex three dimensional geometries including overhangs can be produced. Non-melted powder thereby acts as a support structure. The process is held under an inert gas atmosphere to prevent oxidation. The principal machine parameters in SLM processes are the laser power, the scan rate and the laser spot radius. The powder bed is characterized by the material, the packing density and the particle size distribution. These factors define the structure of SLM finished parts. Up to date, the material and process development of SLM mainly relies on experimental studies that are time intensive and costly. Simulation tools offer the potential to gain a deeper understanding of the process - structure - property interaction. This can help to find optimal process parameters and to individualize AM manufactured parts.

In this project, a powder scale simulation tool is developed. The numerical method is the recently developed Optimal Transportation Meshfree Method (OTM). It belongs to the class of Galerkin meshfree methods. The advantage of meshfree over conventional mesh based techniques is that the treatment of moving boundaries between the liquid melt flow and the solid domain is intrinsic to the formulation. A continuum framework for the finite deformation phase change problem is developed.