Determination of critical and optimal powder loading for 316L stainless steel for Powder Injection Molding process

Powder Injection Molding (PIM) uses the shaping advantage of injection molding but is applicable for metals and ceramics. Powder loading is one of the important factors that have a great distribution on rheological behaviors. In this paper feedstock was made from mixtures of metal powder with particle size of 5μm and the binder of 55% Paraffin Wax, 40% Polyethylen and 5% stearic acid. Four kind of feedstocks were prepared at the powder loading of 60, 64, 68 and 72%. Powder loading have been adapted to injection and tested to find out an optimum feedstock. The optimal powder volume loading has been chosen 68% for 316L stainless steel feedstock. This sample shows the minimum sensitivity to shear rate and temperature and in a wide range of temperature has a nearly steady viscosity, consequently demonstrate the best behavior during injection molding.