Analysis and Characterisation for 316L Stainless Metal Micro-Structure Replication of Micro-Components Produced by Micro-Powder Injection Moulding

In recent years, micro powder injection moulding (mu PIM) becomes a promising process for the replication of metallic micro-structures because of its mass manufacturing capability and a relatively low component cost. In this study, the processing of 316L stainless steel microstructures with a mixture based on polypropylene (PP), paraffin wax (PW) and stearic acid (SA) by micro-powder injection moulding (mu PIM) is described. The optimum binder composition has been determined by torque measurements during mixture and rheology. The metallic feedstocks with powder loadings of 60% in volume have been prepared using a mixture equipment. A suitable formulation for micro-powder soft embossing was chosen and characterized by torque measurements, rheological in order to evaluate the behaviour and homogeneity of feedstocks. The mould design has been carried out using an appropriate CAD software. The structured mould with micro-cavities has been manufactured by high speed milling and micro-electro discharge manufacturing and then has been used for micro powder injection moulding. The injection tests have been carried out on an electric injection press. The results show that the feedstock can be used for the replication of the microstructures with proper shape retention characterisation. This study also revealed that, the increasing of the barrel temperature, mould temperature and the injection speed, improves the capacities of the polymer to fill the micro-cavities.