Powder deposition in three parallel-oriented dies of cylindrical and E shapes

Abstract

The second generation pressure deposition tester (PDT-II) was used to evaluate the die filling process in multiple dies. Three parallel-oriented dies of cylinder and E-shape were filled with an alumina powder at different feed shoe speeds. The results indicated that for cylindrical dies at lower feed shoe speed, the center area had the highest pressures; at higher speed, pressure distribution was irregular, complicated, and varied more. One reason for this was relatively low bulk density and small particle size of the powder, which led to relatively poor flowability. For E-shaped dies, due to wider opening of the middle leg, its pressures were higher than those of the other legs. Compared to another powder (BPM) with denser, bigger, and less spherical particles, the alumina powder had the highest final pressures closer to the middle leg, instead of being closer to the back as for the BPM. This was basically due to its physical properties (such as particle size and shape). This research demonstrated that powder physical properties, such as particle size and shape, had pronounced effect on powder deposition. Also, die shape complexity could affect the pattern of powder flow and deposition.