Abstract: The car reflectors were taken as an object of analysis, mold temperature, melt temperature, pack pressure as well as pack time were selected as the test variables, with the volume shrinkage rate and warpage as the optimum goal. The second order response surface model which described the relationship between test variables and optimum goal was established by BoxBehnken design method. Optimal sequences were found out after the variance analysis by using the DesignExpert software, and the optimal results were forecasted by the optimal sequences. Based on the optimal sequences, accuracy of model could be verified by the simulation analysis with Moldflow. The results demonstrated that optimization adopting response surface model was an effective way of improving quality of products.

Key words: volume shrinkage rate, warpage, BoxBehnken test design, response surface model, optimal design