A numerical study of processing parameters and their effect on the melt-track profile in Laser Powder Bed Fusion processes

Mathematical models provide valuable insight into the Laser Beam Powder Bed Fusion (PBF-LB) process. Numerical modelling of the PBF-LB process and the influence of the process parameters on the melt pool topology are presented in this study. A one-way coupled model using Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) is adopted to model the particle distribution in the powder bed and the melt pool formation and dynamics due to laser irradiation during the PBF process. The DEM method is used to model the interaction between particles in the powder bed, and CFD is used to simulate the melt pool formation, flow and solidification. The Volume of Fluid (VoF) approach was used to model the three phases. The effects of surface tension, Marangoni convection and recoil pressure at the metal/gas interface were included in this model. The predicted melt pool dimensions for various process parameters are validated against the experimental data. The different pore-forming mechanisms in multi-track, multi-layer cases and the effect of actual layer thickness are investigated. The proposed modelling approach is shown to capture the dominant physical mechanisms of the PBF-LB processes, potentially being used as a tool to understand process-structure-property relationships and aid in process optimisation.

Automated summary

This study presents a numerical model of the Laser Beam Powder Bed Fusion (PBF-LB) process that incorporates Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM). The model successfully captures the particle distribution in the powder bed and the formation and dynamics of the melt pool. It considers factors such as surface tension, Marangoni convection, and recoil pressure at the metal/gas interface.