Influence of Die Filling and Powder Transfer on the Density Distribution after Compaction

摘要

Experimental and numerical studies are presented of the behavior of a Distaloy AE powder during powder transfer (ie the parallel movement of punches from their filling position to their starting position prior to compaction). The resulting inhomogeneous density distribution is assessed after both the filling and transfer stages by discrete element simulation. Following transfer, a depression at the top of the cavity is observed experimentally. The discrete element computations explain this response in terms of the circulation patterns induced in the powder as a result of the transfer process. The profile of the powder in the die and the density distribution after transfer provide the initial conditions for a finite element simulation of the compaction process. These computations employ a material subroutine based on the Drucker-Prager-Cap model implemented in the finite element code ABAQUS/Explicit~(~R). A sensitivity study is carried out to determine how the density distribution and the depression following transfer influence the green body's final density distribution.