09. Heat and Mass Transfer

This study applies Computer-aided engineering (CAE) finite element simulation to an injection molding which is used on thick-wall lens in the automotive industry. For injection molding, the conformal cooling channel is regarded as a solution for uniform temperature distribution. However, the complex and special-shaped have problems in terms of manufacturing cost and efficiency. Considering that this is not the best solution, our team evaluate the cooling efficiency and manu-facturability at the same time. As a result, we use the characteristics of turbulence to design a disturbance structure in the flow channel. In addition to increasing the fluid contact surface, the characteristics of turbulence also increase the heat transfer efficiency. The study apply the vertically and horizontally structure of ribs like the water separator which enhance the ability of turbulence to achieve more heat transfer and exchange than straight-drilled cooling channels in the mold. According to numerical simulation, the result show that the cooling time can be reduced more than 10% when molding a plastic product which is difficult to cool like thick-wall lens. Not only decreasing the cycle time, but improving the dimensional accuracy as well. Especially on the defect about the warpage, the shrinkage and thermal residual stress induced during the molding process, the study confirm that the uniform temperature distribution can improve it designed on staggered structure in commercial simulation program.