Particle scale numerical modelling of heat transfer and melt pool dynamics in selective laser melting

Selective laser melting (SLM), with the advantages in producing complex geometry, is becoming one of the most promising additive manufacturing (AM) technologies [1]. In order to understand the multiple physical phenomena which is crucial for successful manufacturing during SLM process, different computational models that are less expensive but challenging compared with experiments and real-time monitor technologies have been developed in the past years. In order to investigate particle scale thermal-physical phenomena in SLM process, a three-dimensional model considering Fresnel reflection is developed to and the volume of fluid approach is used to track melting and solidification phenomena. Numerical results show that the melt track is broken into several regions to minimize surface energy because of surface tension. The molten liquid tends to flow outwards from the laser spot caused by Marangoni effects. The solidified surface of multiple particle diameter powders is much rougher compared with powder bed with layer thickness of one particle diameter. The developed model provides a comprehensive understanding about physical phenomena during SLM process.