Assessment of the powder spreading parameters for non-spherical polymeric powder used in powder bed fusion process: A DEM simulation study

In this study, a Discrete Element Method (DEM)-based model was developed to simulate the powder spreading process in Powder Bed Fusion (PBF) using non-spherical Polyamide 6 (PA6) powder. Various spreading tools—including sharp blades, curved round blades, flat blades, a roller, and a rigid rake-style brush—were tested at three spreading speeds (3, 30 and 90 mm/s) to evaluate their impact on powder bed characteristics. Key metrics such as packing fraction (η), compressive force distribution, spreading density ratio, and surface roughness were analysed within a defined area of interest. Particle velocity distribution and the vertical-to-horizontal velocity ratio were investigated to understand particle dynamics and settling behaviour during spreading. Results revealed that curved round tools, especially the horizontal round blade and roller, delivered denser, smoother, and more uniform powder layers. In contrast, sharp and flat blades caused poor compaction and elevated roughness, especially at higher speeds. The brush and 135° blade showed moderate but consistent performance. These findings emphasize the importance of tool geometry–speed interaction and provide insight for optimizing spreading strategies in PBF processes.