CORRELATING PARTICLE SIZE DISTRIBUTION TO PACKING FACTOR AND SIZE SEGREGATION TENDENCY IN SPHERICAL POWDERS

摘要

Variations in packing density and size segregation in powders during capsule filling under mechanical vibration have been known to cause non-uniform shrinkage during the production of near net shape (NNS) components via hot isostatic pressing (HIP). It is important to understand these two factors in order to ensure optimal shape control and to minimize part-to-part variations. It has been previously reported in the literature (by Fiske et al.1) that particle size distribution can be used to calculate the theoretical packing factor and segregation tendency in spherical powders. However, their model has only been applied and validated using a mixture of two mono-sized powders. In this study, we have extended the applicability of this model to predict the theoretical packing factor and segregation tendency for the continuous particle size distribution of typical commercially available spherical powders with continuous particle size distributions. The predicted model results are compared with the actual measurements to assess the validity of the model in real world applications.