Optimization of thin wall structures in SLM

Selective Laser Melting (SLM) is a layer wise production technique enabling the production of complex metallic parts. In the SLM process parts are built by selectively melting subsequent layers of powder by a laser beam. Nowadays during SLM fixed scan parameters are used (laser power, scan velocity and scan pattern) that should ensure the formation of a sufficiently large and stable melt pool fusing powder particles together. The stability of the melt pool formed during SLM should ensure adequate part accuracy, surface roughness and part density, and thus good mechanical properties. However, the local geometry of the part being build has a large influence on the thermal behavior in and around the melt pool and therefore on the quality of features, mainly when melting along thin walls, sharp corners or down facing layers (layers above powder) that largely influences the local thermal behavior. Detecting such features from the CAD model and using locally adapted scanning parameters for processing those features enables to optimize the quality and density of the part, independently of its local geometry. This paper studies strategies to build thin walls with correct dimensions using locally optimized scan parameters.