A multiphysics simulation approach to selective laser melting modelling based on cellular automata and lattice Boltzmann methods

Abstract

This paper presents a novel approach to numerical modelling of selective laser melting (SLM) processes characterized by melting and solidification of the deposited particulate material. The approach is based entirely on two homogeneous methods, such as cellular automata and Lattice Boltzmann. The model components operate in the common domain allowing for linking them into a more complex holistic numerical model with the possibility to complete full-scale calculations eliminating complicated interfaces. Several physical events, occurring in sequence or simultaneously, are currently considered including powder bed deposition, laser energy absorption and heating of the powder bed by the moving laser beam leading to powder melting, fluid flow in the melted pool, flow through partly or not melted materials and solidification. The possibilities and benefits of the proposed solution are demonstrated through a series of benchmark cases, as well as model verifications. The presented case studies deal mainly with melting and solidification of the powder bed including the free surface flow, wettability, and surface tension. An example of process simulation shows that the approach is generic and can be applied to different multi-material SLM processes, where energy transfer including solid–liquid phase transformation is essential, by integrating the developed models within the proposed framework.