Spatter transport in a laser powder-bed fusion build chamber

Abstract

The adverse effects of spatter particles are well known in laser powder-bed fusion (LPBF) additive manufacturing. To prevent the deposition of spatter particles, an inert gas flow is commonly used to transport these spatters away from the build plate. However, the inert gas flow does not remove all spatters due to varying spatter sizes and ejection angles. Therefore, it is essential to understand and predict spatter trajectories to achieve superior LPBF parts. The present study focuses on numerical modelling of spatter trajectories in Renishaw AM250 using an Eulerian-Lagrangian discrete phase model. The argon velocity profile and spatter trajectories with and against the flow are computed for various materials, sizes and ejection angles. The simulation results are validated with experimental results and show a presence of uneven flow due to inlet geometry along with varying flow profiles across the build height due to inlet location. Spatter analysis shows three methods which result in spatter deposition. Spatter particles either fall directly on the build plate, are transported by the airflow or are re-directed in the recirculation zone. The findings presented in this work indicate the importance of build chamber design along with material-based parameter optimization that results in maximum spatter removal.