Evaluation for multiple processing parameters in selective laser melting based on an integration of mesoscale simulation and experiment method

Selection reasonable processing parameters for the metallic product by selective laser melting (SLM) is a significant issue to improve the performance of the final product. The optimization for the performance of the product is caused by the comprehensive effect of multiple processing parameters instead of a single parameter. It is urgent to propose a method for evaluating this comprehensive effect, furthermore, providing reasonable processing parameters. In this study, the mesoscopic features (molten pool morphology, free surface, porosity distribution, etc.) under different processing parameters are analyzed. Meanwhile, a powder scale thermal-fluid coupled model is established considering the randomly distributed powder bed and the complex physical phenomena within the molten pool. The simulation results are compared with the results characterized by multiple experimental methods. The integration of simulation and experiment results show that a fast scanning velocity or a large hatch spacing would decline the quality of the final product. A high energy density could decrease the roughness of the free surface but increase the porosity. Selecting a moderate energy density through a comprehensive comparison of multiple indicators is critical to evaluate the quality of metallic products by SLM.