Optimization of injection molding process based on fuzzy quality evaluation and Taguchi experimental design

摘要

This paper presents the multi-objective optimization in injection molding. The aim of this study is to determine the best alternative for the best moldability index and better alternatives which are close to the best alternative for an injected part in injection molding technology. Consideration of Taguchi and fuzzy analytic hierarchy process (FAHP) with technique for the order performance by its similarity to the ideal solution (TOPSIS) offers an efficient use approach to evaluate different objectives. Three common defects which reduce the final quality of the injected parts are short shot possibility, shrinkage rate and warpage. The selected material for injection is polypropylene. L18 orthogonal array of Taguchi is selected and for gaining accurate results, Finite Element Analysis (FEA) is applied. To validate the simulation result, the experiment is carried out for two circular flat plates with thickness of 1mm. Finally, the highest moldability index is related to trial 2 for both simulation and experimental results. This study outcome shows instead of having one trial number which has the highest moldability index, there are 10 trial numbers with high moldability index between 0.6–1 for simulation results and 5 trial numbers with high moldability index between 0.6–1 for experimental results. It is clear, by using Taguchi with TOPSIS and FAHP if the best alternative is not possible to maintain, there are other alternatives which are very close to the best alternative with high moldability index. The main advantage of the proposed method is to increase the number of alternatives which in turn increases the moldability of the final product in injection molding.