Factors and optimal operating condition of process factors affecting the quality of polyethylene terephthalate bottle

Abstract

The defect of plastic drinking water bottle with indent in the center of bottom is a symptom that causes the defect in the case study. Quality improvement of the product and manufacturing process could be accomplished by determining process factors and optimal operating condition of the significant factors affecting the difference between the maximum and minimum values of thickness of the bottle in the plastic injection molding process. The Shainin design of experiment method was used to investigate the effect of six process factors on the quality of plastic drinking water bottle. Further-more, analysis of variance and multiple comparisons were used to determine the optimal operating condition of the significant factors. The results showed that injection time was the only significant factor affecting the average difference between the maximum and minimum values of thickness of the bottle with the optimal operating condition of 11 seconds used for reducing the amount of waste.