Abstract
Previously, we have optimized a cooling pipe layout so that an injected plastic product is cooled down uniformly and rapidly in order to reduce residual stress that is one of the factors of defects in the molded products. But there are many other factors affecting generation of residual stress such as die temperature, coolant velocity and coolant temperature. In this paper, the cooling conditions and the cooling pipe layout are optimized simultaneously for the reduction of residual stress in plastic products. In the optimization processes, the basis vector method controls a cooling pipe layout and the design of experiment (DOE) decides a combination of levels of cooling conditions and basis vectors. Then numerical simulation based on DOE is adopted to calculate a temperature distribution in the die. An optimum layout and cooling conditions to optimize a response surface constructed by the numerical results are obtained.
