Powder Packing Density and Its Impact on SLM-Based Additive Manufacturing

Packing density of metal powders is an important aspect of additive as it directly impacts the physical and mechanical properties of printed products. In order to achieve the most efficient packing of a powder, different grades of that powder must be mixed together in such a way that we minimize the voids. Research has shown that packing the coarser grains first not only yields higher density powders but also decreases balling defects in the finished printed product. In this study, we developed a simple model that adequately predicts the volumetric fractions of different powder grades that can yield the highest powder density. The model accounts for the disparities between theoretical assumptions and experimental outcome, such as volume reduction. The model equations, based solely on void ratios and true specific gravity, will be validated experimentally and compared to other modeling efforts in literature to further prove the potency of the model.