Micro scale 3D FEM simulation on thermal evolution within the porous structure in selective laser sintering

A micro scale 3D finite element model (FEM) with consideration of powder arrangements was developed by selective laser sintering (SLS), where a multi-layer powder stacking model with cubic powders interlaced each other was established to describe the porous powder bed. All the powders directly exposed to laser irradiations were loaded with the Gaussian function of heat flux, and the non-linear thermal conductivity and specific heat owing to temperature change and phase transformation were considered. Comparison between the modeling and experiment indicated that both the simulated length of the sintered piece and shrinkage depth of the powder bed agreed well with the experiment data. The temperature field of laser sintering was intermittent in the micro scale due to the discretely distributed particles with maximum temperature produced in the top layer of the powder bed, and two primary ways of bonding were found in the powder bed during laser sintering.