Shape effects in binary mixtures of PA12 powder in additive manufacturing

The quality of powder spread in additive manufacturing devices depends sensitively on particle shapes. Here, we study powder spreading for mixtures of spherical and irregularly shaped particles in Polyamide 12 powders. Using DEM simulations, including heat transfer, we find that spherical particles exhibit better flowability. Thus, the particles are deposited far ahead of the spreading blade. In contrast, a large fraction of non-spherical particles hinders the flow. Therefore, the cold particles are deposited near the front of the spreading blade. This results in a temperature drop of the deposited particles near the substrate, which cannot be seen with spherical particles. The particles of both shapes are homogeneously distributed in the deposited powder layer.