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. • Powder spreading of PA12 with spherical and non-spherical particles is studied. • Flowability improves with spherical particles in PA12 powder spreading. • Non-spherical particles hinder flow and accumulate near the spreading blade. • Non-spherical particles cause temperature drops in the deposited powder layer. • Particle shapes are evenly distributed in the final powder layer.