Parametric characterization of the thin-wall injection molding of thermoplastic composites

Thin wall injection molding of thermoplastic composites has become an important process in industry because of its light weight, relatively lower resin cost per part, and faster cycle time. An experimental study, based on the Taguchi orthogonal array design, was conducted to characterize the effect of different processing parameters on the thin wall injection molding of thermoplastic composites, including melt temperature, mold temperature, filling speed, filling pressure, packing pressure, and packing time. Three materials were used in the study: virgin acrylonitrile-butadiene-styrene (ABS) and 20% and 30% glass-fiber filled ABS composites. Experiments were carried out on an 80-ton reciprocating injection molding machine. After molding, the weight of the molded composite parts was determined. For the factors selected in the main experiments, melt temperature and melt filling pressure were found to be the principal parameters affecting the thin wall injection molding of thermoplastic composites. Glass fiber filled polymers required a higher filling pressure and melt temperature for successful molding than those of the non-filled polymers. In addition, a moldability diagram was developed based on the statistical results to give first guidelines for system optimization.