Characterization of powder bed generation in electron beam additive manufacturing by discrete element method (DEM)

The dynamic behavior of a collection of powder during raking process was simulated by utilizing discrete element method (DEM), aiming at obtaining powder packing features of powder layer, which are valuable for electron beam additive manufacturing. For a better matching between simulation and real process, the mechanical model of particulate system was modified. The simulation results revealed that powder packing density increased with increasing layer thickness, and the powder with better flowability was favored for higher packing density and uniformity of powder layer. The mixture of powder with large and small mean size can increase packing density in some degree, but it was found to be detrimental to the powder flowability.