Friction-assisted pressing of PM components

Abstract

Friction between powder and tools plays a major role during cold compaction of PM components with results on the inhomogeneous densification present work deals with a new method of compaction for PM components by using the friction force between die and compacts as an active pressing force in order to reduce the density gradient. The proposal technique consists in moving the container of the die, during pressing stage to the punch direction according of a particularly speed. As a result, the friction force acts in the same sense as the pressing load with better distribution of powder flow during compaction. The experimental results of compaction parameters versus density, for Al and 316L stainless steel across the height of cylindrical specimens, have proved the decreasing of the density gradient by increasing container/punch speed rate, even for high and low h/ d geometrical factor. A sharp density gradient on the specimen height moving container contrarily to the punch.