Particle-based simulation, dimensional analysis and experimental validation of laser absorption and thermo-viscous flow during sintering of polymers

Smoothed Particle Hydrodynamics simulations are used to study the thermo-viscous flow on the powder particle length scale. The effects of laser absorption, latent heat, thermal diffusion, melting and re-solidification, viscous diffusion, surface tension, Marangoni currents and gravity are considered in the model. Influences of varied laser scanning parameters are analyzed. The strongly different time scales of laser absorption, heat conduction and viscous flow as well as the transient behavior of temperature and strain rate observed in the simulations are predicted with good accuracy by a dimensional analysis. The simulation results for the transient surface temperature are validated by infrared camera measurements.