Development and evaluation of a new rapid mold heating and cooling method for rapid heat cycle molding

A new rapid mold heating and cooling method is developed in this study. For rapid mold heating, cartridge heaters are assembled in the holes of the mold. Between the heaters and the corresponding mounting holes, there are annular gaps which are full of water. During mold heating, the heat generated by the heaters passes through the water gaps firstly and then transfers into mold base to raise cavity surface temperature. For rapid mold cooling, pressured cooling water is passed though the annular gaps. Firstly, a cell model was established to evaluate the effectiveness of the new rapid mold heating and cooling method. Thermal response analysis based on numerical simulations was conducted to investigate the influences of the gap size, the power density of the heaters and also the layout of heaters on thermal responses of the cavity surface. Further, the injection mold of a large LCD TV frame was designed and manufactured based on the developed rapid mold heating and cooling method. Both numerical simulations and experiments were performed to evaluate the thermal response efficiency of the cavity surface. The results show that the cavity surface temperature can be changed in a large temperature range within relatively short time. The simulation results are consistent well with the experimental results, which verifies the effectiveness of the established analysis method. Finally, production testing was conducted to produce the LCD TV panel. The results show that the weld marks on the outer surface can be eliminated completely and the outer surface gloss of the part can reach higher than 90 GU with a molding cycle of about 60 s. The consumption of energy and water can be greatly reduced by comparing with other conventional rapid mold heating and cooling methods.