Influence of Processing Parameters on Injection Molded Polystyrene Using Taguchi Method as Design of Experiment

The influence of processing parameters onto the tensile properties, which also indicating the failure rate indirectly, of injection molded polystyrene (PS) was investigated. Dumbbell samples were being molded and tested for tensile properties by using Taguchi method as a robust design of experiment. The tensile properties of PS samples were analyzed accordingly and showed that the introduction of weld line, polymer melt temperature and the mold temperature were among the parameters of significant effect onto the strength of PS samples, where the introduction of weld line giving the most influence on material strength. Heat reversion showed that the change in material strength was due to the difference in residual stress and Ubbelohde testing showed that thermal degradation was minimal and had little effect on the material strength. The CADMOULD simulated results showed that the effects of processing parameters were not that great and was due to the software treat samples with and without weld line very differently.