Thermal Modeling and Simulation of Metals Additive Manufacturing

Abstract

Additive manufacturing (AM) enables a layer-wise approach to near-net shape fabrication of three-dimensional computer aided designs. In powder-metal-based AM processes, such as directed energy deposition (DED) and laser-powder bed fusion (L-PBF), a laser is used as the heat source to partially/completely melt the powder material. In the current work, both manufacturing processes are numerically modeled to understand the thermal behavior during powder/laser-based AM processes, and the effects of process/build parameters are studied. Common AM materials such as Ti-6Al-4V, stainless steel 316L and Inconel 625 are examined in the current work due to their industrial use. Scan-wise and layer-wise manufacturing effects on heat transfer are quantified via peak melt pool temperature and resulting melt pool morphology. Both powder effects and phase change within the melt pool are considered using approximate, reduced-complexity techniques. The employed numerical model has been validated using data available in the literature. Results demonstrate that the melt pool morphology and temperature distribution along build geometries with negative draft angles are significantly different than those with positive draft angles during L-PBF. Additionally, the proposed analytical model has been successfully validated to predict thermal distribution within the bulk-region of thin walls manufactured via powder/laser DED.