Experimental and numerical study of die filling, powder transfer and die compaction

Abstract

Experimental and numerical studies are presented of the behaviour of a Distaloy AE powder during filling and transfer (i.e. the parallel movement of punches from their filling position to their starting position prior to compaction). Discrete element simulations provide information about the density distribution in a die after filling and how this is modified during transfer. The transfer process creates a depression in the top of the powder. The discrete element computations explain this behaviour in terms of the circulation patterns generated 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 employed a Drucker–Prager–Cap model, which was implemented in the finite element code ABAQUS/Explicit, using a user material subroutine. A sensitivity study is presented which evaluates how the density distribution and depression created during filling and transfer influence the green body's final density distribution.

Keywords:

• DIE FILLING
• POWDER TRANSFER
• DIE COMPACTION
• DEM
• FE