Warpage of film insert molded parts and optimum processing conditions

Three dimensional flow and structural analyses were carried out for film insert injection molding in order to evaluate the warpage and long term viscoelastic deformation of the film insert molded (FIM) tensile specimen. The predicted warpage after ejection and annealing was utilized as the input to the orthogonal array in order to obtain priority of significant factors and optimum molding conditions. Various injection molding factors influenced the degree of shrinkage of the injected substrate, i.e., packing pressure and mold wall temperature difference determined warpage of the FIM part after ejection. Warpage of the annealed FIM part was affected mainly by heat treatment conditions of the inserted film and annealing time of the part because annealing conditions had larger effects than the other processing factors. Optimum processing conditions and the relative significance of processing factors were obtained for warpage of FIM parts by using the Taguchi's method.