| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 106 === In this research, we first did the analysis of melting region and surface profile on single track experiment samples by selective laser melting(SLM) from ITRI for stainless steel SS316L.After the analysis of experimental sample, we built the numerical model for SLM with COMSOL Multiphysics by separating the temperature field and fluid field in numerical model, to simplify the analysis process in selective laser melting. We first used the laser volumetric heat source mode to calculate the temperature field in heat transfer model with the simulation of laser beam interacting with powder bed, melting pool and vaporization region. The error percentage between theoretic and experimental values for melting track width and depth in our research was in a range of 5~20%. Based on the solution of temperature field, we used phase field model to simulate the gathering process of melting pool driven by surface tension, and get the solidification height by the appropriate assumption for refilling mechanism in vaporization region. Finally, we compare the experiment results of single track to single layer, and found out the relationship between surface quality of single layer with the melting pool dimensions of single track. We get the result that with the higher value of aspect ratio and smaller contact angle of melting pool with substrate, the surface roughness will be smaller, and we can get the better surface quality in single layer of SLM.
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