Understanding laser-metal interaction in selective laser melting additive manufacturing through numerical modelling and simulation: a review

Selective laser melting (SLM) is the most used and versatile technique for additively manufactured metallic parts. Due to its unique flexibility in enabling the fabrication of complex geometries, it has received great attention, especially in very demanding industries such as aerospace and automotive. Improving this process requires a better understanding of laser-metal interactions, something that can be achieved by relying on numerical modelling as a cost-effective alternative to experiments. This review focuses on laser-metal-powder interactions, with an emphasis on powder-scale modelling and simulation, to elucidate the powder-part relationship. Through a comprehensive meta-analysis of the physical processes and the existing numerical modelling methodologies, this review exposes the advancements in both virtual powder bed generation and ways of carrying out multi-physics computations. Process optimisation with meta-modelling and machine learning are also critically discussed, with clear evidence of their capabilities and limitations.