A simple model for viscosity of powder injection moulding mixes with binder content above powder critical binder volume concentration

A simple model is proposed for the variation of viscosity of powder injecti on moulding mixes with binder content above Critical Binder Volume Concentr ation (CBVC), a characteristic of powder. Coarse silica and fine alumina po wders are mixed with different types of low viscosity binders at different binder proportions. The viscosities of these mixes are measured by capillar y rheometry with a special die at different shear rates. The CBVC values of the powders estimated by the model from the viscosity data of the mixes ar e matching with those values arrived from the experimental torque rheometry and temperature measurement methods. The proposed model has shown excellen t correlation between the calculated and experimentally measured viscosity data at different shear rates, binder contents with different binders and p owders. The model also gave precise CBVC values with the viscosity data of the previous authors validating the model to other powders and binders. The model is useful for the prediction of viscosity of PIM mix with known bind er content, viscosity of binder and CBVC of the powder. (C) 2000 Elsevier S cience Ltd. All rights reserved.