Simulation of pore evolution under laser remelting in SLM process

In the process of selective laser melting (SLM) forming, pore defects can seriously affect the quality of formed parts. In this paper, the effectiveness of laser remelting to eliminate the pore defects of SLM formed parts was analyzed experimentally. Based on the level set method, a numerical simulation of multi-physics finite element model was established to analyze the mechanism of pore evolution during laser remelting. It is found that the pore evolution is significantly affected by the Marangoni effect at the micro scale. Affected by the Marangoni effect, during the evolution process, the porosity doesn't rise vertically. Instead, it moves towards the tail area of the molten pool while rising. The essence of pore evolution is fluid mass transfer. Moreover, the effectiveness of laser remelting in eliminating porosity has been verified through experiments.