Investigation on Surface Roughness in Electron Beam Selective Melting by Mesoscale Model

Modeling and simulation in meso-scale have been used to investigate the complicated physics involving powder behaviors during the forming process in electron beam selective melting. But it is difficult to quantitatively predict the forming quality of parts due to the huge calculation amount for multi-layer and multi-pass cases. In this paper, we presented a novel frame for investigating the side surface roughness of fabricated components based on single-track simulation. An integrated model of selective beam melting with considering the random distribution powder particles was developed. The surface morphologies of simulated tracks were used to calculated the surface roughness, and the calculated results were validated by experiment data from independent literature. The effects of heat input were discussed in detail. It reveals that the side roughness increases with a lower heat input. The mechanism behind is the fluctuation of tracks induced by the asymmetry of molten pool, which is related to the coalescence of melting particles and unevenness of powder distribution.