Coupled Computational Fluid Dynamics-Discrete Element Method Model for Investigation of Powder Effects in Nonconventional Laser Powder Bed Fusion Process.

Abstract

The present study proposes a comprehensive 3D computational fluid dynamics-discrete element method (CFD-DEM) coupled simulation model to investigate the particle dynamics induced by SS316L metal vapor spouting during single-scan-track laser powder bed fusion (L-PBF) processing. The model provides the ability to examine the effects of nonconventional process variables such as the chamber pressure and gravitational force on the suppression of the spatter and denudation phenomena. The simulation results imply that adjusting the gravitational force provides an effective technique for suppressing both spatter formation and powder bed denudation. In addition, the chamber pressure has only a marginal effect on the denudation phenomenon. In particular, under a higher operating pressure, the metal vapor tends to spout in the upward direction, while under a lower pressure, the spouting is more radially distributed. As a result, the simulation results obtained in this study have suggested that the chamber pressure and gravitational force may both provide feasible approaches for suppressing the spattering and denudation phenomena, particularly in the L-PBF processing of light-weight materials.