Research of thermal response simulation and mold structure optimization for rapid heat cycle molding processes, respectively, with steam heating and electric heating

The dynamic mold temperature control system is the key of rapid heat cycle molding (RHCM) technology because it significantly affects the stability of the process, productivity and the quality of the final polymer part. For this reason, the approaches and techniques for dynamic mold temperature control were discussed in this study and two different dynamic mold temperature control methods, respectively, with steam heating and electric heating were found to be very feasible in mass production. The methods and principles of mold design for the two RHCM technologies were also discussed and then several different kinds of mold structures were designed. By constructing the corresponding thermal response analytical models for these RHCM molds, the temperature responses of the molding systems in the heating and cooling process of RHCM were simulated and studied. The effects of the mold design parameters such as the insulation layer between mold plate and mold inert, and mold material, on thermal response efficiency and temperature uniformity of the two RHCM processes were analyzed based on the simulation results. The results show that the insulation layer can increase the upper limit temperature of RHCM with steam heating and improve the heating speed of RHCM with electric heating. It can also greatly decrease the energy consumption of the two RHCM processes. The heating efficiency of RHCM with steam heating can be effectively improved by increasing the thermal conductivity of the cavity/core material, while the situation is diametrically opposite for RHCM with electric heating. Therefore, we acquired an optimized mold design principle and method for RHCM with steam heating and electric heating, respectively. Finally, a new electric heating mold with a cooling plate was proposed to enhance the cooling efficiency. The thermal response of this new electric heating mold was also simulated. The simulation results show that the cooling plate can significantly improve the cooling and heating efficiency. (C) 2009 Elsevier Ltd. All rights reserved.