A simple method of improving warpage and cooling time of injection molded parts simultaneously

Conformal cooling channels (CCCs) are widely employed in the plastic injection molding (IM) due to uniform cooling in the cooling stage. IM is a process that molten materials are pushed into the mold cavity. The cooling stage is an important part in the IM process since it takes most of the cycle time. According to practice experience, it is very difficult to improve the cycle time and quality of injection molded part simultaneously in the conventional straight drilled cooling system. Thus, improving warpage and cooling time simultaneously of the injection molded parts is a critical item in the IM. In this study, an effective method for reducing both warpage and cooling time of the wax patterns was proposed by changing the coolant temperature difference between the core and cavity inserts. It was found that both core insert with series connection CCCs and cavity insert with parallel connection CCCs is a good combination in the IM mold. The cooling efficiency of the core insert is increased from 42 to 54%, while the coolant temperature difference between the core and cavity inserts is 2 °C. The average deformation of the injection molded parts can be improved by 75.2%. The cooling time of the injection molded parts can be further reduced by 6%. The cooling time of the injection molded parts can be saved by about 30%, and the average deformation of the injection molded parts can be improved by about 60% compared with IM mold embedded with conventional cooling channel. The mechanism to minimize the amount of warpage of injection molded parts using coolant temperature difference between the core and cavity inserts is presented. Finally, the proposed method is also verified by practical implementation and comparison with experimental data. The experimental results found that the improvement rate of the average deformation of the molded parts is up to 74.5% and the cooling time of the molded parts can be reduced by approximately 15.7%. The variances compared with the simulation results are approximately 0.7% and 9.7%, respectively.