Modelling die filling for powders with complex rheology: A new DEM contact-model

Die filling as the first step in the process chain of die compaction can already introduce various kinds of flaws like undesired density variations, which are difficult to repair later on. Predictive modelling of the complete die filling process including effects of powder handling history on rheology can assist in the optimization process to avoid such effects. However, the rheology of powders can be very difficult to model especially if heterogeneous agglomeration or time dependent consolidation effects occur as could be the case for powders containing organic binders. In this paper, we present a new discrete-element contact-force model that enables modelling complex powder flow characteristics including direct time dependent consolidation effects and load history dependent cohesion to d escribe the filling process of complex, difficult to handle powders.