Effect of powder morphology on flowability and spreading behavior in powder bed fusion additive manufacturing process: A particle-scale modeling study

Abstract

Improving the quality of the powder bed is of great interest in the powder bed fusion-based additive manufacturing (PBF-AM) process to reduce micro-defects in the final product. We investigated the influence of particle morphology on flowability and spreading behavior using a discrete element method (DEM) simulation with multi-sphere modeling. The addition of non-spherical particles effectively decreased the flowability under gravity and rotation, resulting in a transition from rolling flow to cascading flow in the rotating condition. In the powder spreading process, the quality of the powder bed was decreased by adding elongated particles, owing to the frequent force-arch formation and additional wall effect caused by strong particle interlocking. Furthermore, the high spreading velocity facilitated loose powder packing owing to the frequent force arch and wide rearrangement area. In conclusion, spherical particles with a low spreading velocity are desirable for improving the quality of the powder bed, such as packing density and surface roughness, in the PBF-AM process.