HEAT TRANSFER, PHASE CHANGE, AND COALESCENCE OF PARTICLES DURING SELECTIVE LASER SINTERING OF METAL POWDERS

Flow and heat transfer during selective laser sintering of metal powder is investigated numerically. Heat transfer, melting, and resolidification, which are induced by laser irradiance and coupled with coalescence of partially melted particles, are dominant processes governing laser sintering of metal powders. The present model accounts for phase change during the laser heating and subsequent melt flow due to surface tension forces. The study is aimed to gain understanding of mechanisms governing microstructure formation during selective laser sintering. A two-dimensional boundary element model is used to solve the governing equations. The solid-liquid interface during phase change is tracked using the Stefan condition at the interface. The liquid melt formed due to melting is assumed to be viscous. The influence of process parameters on temperature field evolution, shape evolution, and densification rate is quantified and discussed.