Optimal design of the spiral type of collector die for dry powder compaction

This research presents a new die on principle of the collector method. The collector die of spiral type for uniaxial dry compacting homogeneously dense powdered bodies of complex shape without macroscopic defects has been developed. To reduce the die-wall friction effects collector method is based on the selfalignment of uniform density regions within a green compact. The purpose of this work is comparison of statistical dispersion of local deformation in the volume of ceramic powders compacted using collector die of spiral type and by conventional collector die at certain conditions. A collector die of spiral type was designed for shaping cylindrical compacts (diameter 14 mm, height 40 mm) with 2-12 alternating, oppositely-moving parts of the passive shaping surface of sliders, twisted at an angle of 80 degrees. The results of comparative simulation by FEM showed that dispersion of powder layer deformation for collector die of spiral type can be reduced up to 4-20% if friction coefficient ,u=0.1 and can be reduced up to 5-15% if friction coefficient ,u=0.05. It was shown, that density distribution into powder green compact can be minimized by increasing the number of moving parts of passive shaping surface. Thus it is possible to decrease the density gradients. The collector die of spiral type can be apply to shape uniform-dense cylindrical articles from dry ceramic poly- and nano-sized powders.