Impact of rheological model on numerical simulation of low-pressure powder injection moulding

Abstract

ABSTRACT The aim of this study is to quantify the impact of different rheological models on the accuracy of LPIM numerical simulation. Two different feedstocks were formulated, and rheological profiles were characterised using a rotational rheometer from which the parameters of different rheological models were extracted and then implemented in an Autodesk Moldflow package. Mould filling patterns into a rectangular shape mould cavity were simulated, and then validated using real-scale injections. Depending on the feedstock rheological behaviour, models are not always well adapted to predict the mixture viscosity over the entire shear rate range. Because injections were performed at constant volumetric flow, all the rheological models were successfully used to predict the injected length. However, the simulated pressure through the mould cavity was only accurately simulated using the second-order or matrix models since these viscosity models were able to adequately capture the feedstock behaviour in the shear rate range representing the injections.