Compaction and Ejection of Green Powder Compacts

Abstract

An experimental investigation into the compaction, relaxation, and ejection of bush type components of different length made from iron, bronze, ceramic, and carbon powder types is presented. The compaction phase confirms the effect of friction between the powder and tooling and the presence of consequent density gradients in the compact. The force relaxation between the compaction and ejection phases is shown to be non-elastic for the ceramic powder and only approximately elastic for the other powder types. For the final stage of ejection, the form of the curves is dependent on the compact length, after the initial movement the force decreases in the shorter compact while there is an increase for the longer component. In all cases there is a decrease just before the compact emerges from the die and a linear reduction to a zero value at the end of the ejection process. PM/0627A