A study on the estimation of plastic deformation of metal insert parts in multi-cavity injection molding by injection-structural coupled analysis

Insert parts in insert injection molding used to be deformed by pressure developed during the molding process. The plastic deformation of insert parts caused by injection pressure during insert injection molding for electric power plugs cannot be predicted by conventional injection molding analysis methods. In this study, the injection-structural coupled analysis was carried out to predict the plastic deformation of insert parts. Injection pressure developed during the molding process was calculated by the injection molding analysis software and was mapped onto the grid surface of the inner tube model for structural analysis as boundary conditions. The effect of process parameters such as injection time, melt temperature, and holding pressure on the injection pressure and the deformation of the inner tubes was examined to find the proper molding condition. The result from the analysis was compared to the insert injection molding experiment. Furthermore, the diameters of sub-runners in the multi-cavity mold of the power plugs were optimized to prevent the deformation of the inner tubes by the unbalanced filling of the melt into the linear arranged cavities using the injection-structural coupled analysis.