Mesoscopic-scale numerical investigation including the influence of scanning strategy on selective laser melting process

Selective laser melting (SLM) has become one of the most widely used laser additive manufacturing technologies today. However, the proper selection of scanning strategies is still a key concern for SLM production. In order to quantify the influences of different scanning strategies (One-direction, Two-directions, and Pre-sinter) on the SLM process, this paper calculated the spreading powder process based on the open-source discrete element method framework Yade, predicted the SLM mesoscopic molten pool dynamics behavior based on the open-source finite volume method framework OpenFOAM, and established the simulation flow of the SLM multi-layer multi-path forming process. The influences of different scanning strategies on grain orientation, pore defect, and surface roughness were analyzed and verified in comparison with experimental results. It is found that the grain orientation of the current formed layer under scanning strategies One-direction and Pre-sinter was almost the same as that of the previous formed layer, while the grain orientation of the current formed layer under scanning strategy Two-directions was significantly different from that of the previous formed layer. In addition, the porosity and surface roughness under scanning strategy Pre-sinter were lower than those under scanning strategies One-direction and Two-directions. This paper is expected to provide a basis for the selection of scanning strategies in practical SLM production.