Simulation and optimization of molding process parameters of ployetherimide parts by Taguchi-grey relational analysis combined method

In the process of molding parts using the plastic injection molding method, it is key essential to apply appropriate parameters in order to produce a qualified product. The purpose of this paper is to choose helpful production parameters and optimize them for molding eight different parts made from Polyetherimide. In the beginning, based on the previous research and the capabilities of Mold Flow software, appropriate process parameters were chosen. These parameters were: melt temperature, mold surface temperature, packing pressure and coolant inlet temperature. The simulations in Mold Flow software were done based on Taguchi’s L25 orthogonal array. Afterward, the critical and comparable results including: volumetric shrinkage, sink mark, warpage and the percentage of frozen volume in parts were exported from the simulations. Eventually, the optimizations were made based on these results by applying the gray relational analysis. The optimizing results show that in all distinguishing coefficients of the gray relational analysis (0.1 to 0.9), the melt temperature was 360 °c, the mold surface temperature was 140 °c, the packing pressure was 100% of the injection pressure and the coolant inlet temperature was 12.5 °c lower than the mold surface temperature of the most optimized ones. Also based on the ANOVA results, in all difference indices, parameters of melt temperature and packing pressure were respectively the most effective.