Investigation of the effect of laser energy density on selective laser sintering of PA12 using a multi-physics field simulation method

Selective laser sintering (SLS) polymer powders involve multi-physical field transient phenomena that are critical to the optimization of SLS process parameters but challenging to observe experimentally. In this study, a two-dimensional multi-physics field simulation method was used to couple the thermal-force-flow fields involved in SLS. Laser energy density was introduced to characterize the interaction between process parameters such as laser power and scanning speed, and the free surface evolution, material migration, and molten pool evolution of nylon 12 (PA12) at different energy densities were thoroughly investigated. Accordingly, the optimal process parameters for SLS were determined as a laser energy density of 0.08 J/mm(2), i.e., laser power of 12 W, scanning pitch of 0.12 mm, and scanning speed of 1500 mm/s. The same process parameters were then used to validate the simulation model. Experimental results show that the density, cross-sectional profile, and compression property are also optimal with the same energy density of 0.08 J/mm(2). Full agreement with the simulation results indicates that the multi-physics simulation method provides an effective approach for SLS parameter optimization.