Influence of punch spring back in powder die compaction by FEM analysis.

The effects of tool stiffness on powder die compaction were investigated by performing FEM analysis of the inner flange shape compaction using a Drucker-Prager Cap model. The material parameters of atomized iron and ferrite powders were validated by comparing the results of uniaxial compaction tests with measurement from a die system. The results simulated influence of punch spring back during unloading and ejection. It was found that increasing the lower punch spring back caused a change in the shear stress during unloading and locally increased the residual stress. [ABSTRACT FROM AUTHOR]