Modeling the melt pool of the laser sintered Ti6Al4V layers with Goldak's double-ellipsoidal heat source

Abstract

Selective laser melting process has been widely studied to elucidate the effects of process parameters (laser speed, laser power, scan strategy, hatch distance, layer thickness, etc.) on the manufactured parts. Experimental and numerical modeling studies have been investigating the melt pool shapes of the laser sintered layers to correlate the melt pool geometry with the part quality. Although modeling results agree with the experiments, the melt pool cross-section may form key holing rather than semi-circular shape due to Marangoni effect, recoil pressure, and sudden evaporation for some process parameters combinations. To accurately model the melt pool depth, this study proposes a finite element analysis (FEA) model that simulates the laser source as the Goldak's double-ellipsoidal heat power density model. Single bead experiments of Ti6Al4V were conducted within the processing range of laser sintering system with the 400 W laser, and these experimental results allowed to verify simulated FEA results. © Solid Freeform Fabrication 2018: Proceedings of the 29th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2018. All Rights Reserved.