Abstract:

To improve the injection molding quality of a commode chair panel， a grey relational comprehensive evaluation model based on the TOPSIS was proposed by combining the TOPSIS with a grey relational analysis. The gating system of a plastic part was first optimized and determined， and then the orthogonal experimental design was carried out. The mold temperature， melt temperature， injection time， holding pressure and holding time were selected as experimental factors to simulate and analyze the warpage， shrinkage index and volume shrinkage of the plastic part as evaluation inde?xes using the Moldflow software. According to the orthogonal test data， the weight coefficients of each evaluation index were determined using the CRITIC method， and the multi?objective optimization was transformed into the single objective one using a grey relational comprehensive evaluation method based on the TOPSIS to obtain an optimal combination of process parameters. The experimental results indicated that the volume shrinkage of the plastic part after optimization was reduced by 14.6 %， its shrinkage mark index was reduced by 43.3 %. The warpage deformation was basically the same as that before optimization， and the overall quality of the plastic part was improved significantly.

Key words: technique for order preference by similarity to ideal solution, grey relational analysis, injection molding, quality, multi?objective optimization