Simultaneous optimization in plastic injection molding for weldline temperature and clamping force

Abstract

In plastic injection molding (PIM), the process parameters such as melt temperature, mold temperature, injection time, and so on strongly affect the energy consumption as well as the product quality. It is preferable to produce plastic products with a small clamping force for the energy consumption. Weldlines, which are formed when two or more melt fronts meet, influence not only the strength of products but also the appearance, so it is preferable to reduce the weldlines as much as possible. In order to reduce the weldlines with the small clamping force, a simultaneous optimization of the process parameters in PIM is performed and the pareto-frontier is identified. The weldline temperature is maximized for the weldlines reduction, whereas the clamping force is minimized. The numerical simulation in PIM is so intensive that a sequential approximate optimization using radial basis function network is adopted. The difference between conformal and conventional cooling channel is also discussed. The numerical result shows that the trade-off between the weldline temperature and the clamping force is clarified and the effectiveness of conformal cooling channel is clarified.