Investigations on the Impact Performance of Gas-Assisted Injection Molded Polystyrene Parts

Abstract

The effects of geometrical factors, introduced by part thickness and various gas channel designs, including semicircular gas channel and rectangular gas channels with different geometry, on the impact properties of gas-assisted injection molded (GAIM) polystyrene parts were investigated via impact energy measurement. Test results were also compared with those of conventional injection molded (CIM) parts and plate parts without gas channel. It was found that gas channel design results in part impact reinforcement and gas-assisted injection molded parts show better impact performance than conventional injection molded parts. Generally speaking, impact strength of GAIM parts increases when the size of the gas channel is increased. Meanwhile, for five gas channel designs, both gas channel designs attached with top rib (shapes D and E) show the higher impact energy and impact value. These two gas channel designs provide the best enhancement effect in impact performance. The present investigation provides a design guideline for choosing the most effective gas channel design to achieve the part impact performance.