In the selective laser melting (SLM) process, a three-dimensional part is manufactured based on the formation of numerous molten tracks. Consequently, the generated melt pool in the scanning process of each track exhibits close relation to the internal defect formation and the quality of the fabricated part. In this study, a numerical model of single-track scanning of the SLM process is presented to analyze the melt pool characteristics for various process conditions. The presented model considers the thermal behavior of the powder material including the phase change and densification during the SLM process. The temperature-dependent energy absorption and the increase in effective energy absorptivity due to the keyhole mode melting are also incorporated in the heat flux model to evaluate the process conditions in the presence of high energy density. Moreover, the single-track specimens were manufactured under various process conditions for validation of the proposed model. The predicted melt pool dimensions, as well as the melting modes (Conduction/Keyhole), demonstrated good agreement with the experimental measurements. Based on the analysis results, the process boundaries (Keyhole/Lack-of-Fusion) for the SLM process of AlSi10Mg are provided and the potential application of the proposed model for exploring the process window is discussed.

Heat transfer characteristics in the vicinity of irradiated region of the beam of a selective laser melting (SLM) process affect the creation of the melted region during the deposition. The creation of the molten pool is greatly influenced by laser parameters and powder characteristics. The goal of the paper is to investigate the influence of laser parameters and powder porosity on thermal characteristics in the vicinity of the molten pool of the SLM process through repeated finite element analyses (FEAs). The power and the scan speed are chosen as the laser parameters. The laser is assumed to be a volumetric Gaussian heat flux model. Materials of the powder and the substrate are chosen as SUS17-4PH and S45C, respectively. Temperature dependent thermal properties for those material are used to perform the FEA. An appropriate efficiency of the heat flux is predicted by comparing the results of FEAs and those of experiments. The influence of laser parameters on temperature distributions in the vicinity of the melted region and the formation of the molten pool is examined. In addition, the effects of porosity of powders on heat transfer characteristics in the vicinity of the melted region are discussed.