Optimization of Injection Moulding Process Parameters in MIM for Impact Toughness of Sintered Parts

Abstract

The identification of significant process parameters during injection moulding of feedstock in Metal Injection Moulding (MIM) is essential because fine control is required for these parameters. A small change in these parameters can cause large variation in the impact toughness of the parts produced by MIM. The controlled parameters used for optimization in this work include injection pressure, injection temperature, mould temperature, holding pressure, injection speed, powder loading, holding time, and cooling time. These parameters have been optimized using analysis of variance (ANOVA) for signal to noise ratios obtained in experiment performed by following Taguchi L₂₇ orthogonal array. The ANOVA also provides the contribution of significant process parameters to impact toughness. Results show that the injection pressure, mould temperature and powder loading are highly significant factors to the impact toughness, while the injection temperature, holding pressure, injection speed, holding time, cooling time, the interaction of injection pressure and injection temperature and interaction of injection pressure and mould temperature do not show significant effect at 95% confidence level.