Dynamic Mold Temperature Control Using External Wrapped Inductor Heating Combined with Coolant Cooling

Abstract

Induction heating in injection molding has the advantages of rapid heating, reduced cycle time, and improved product quality. In this research, using both experimental and simulation methods, externally wrapped coil induction heating was applied to verify the heating capacity of a pair of mold plates. By varying coil pitches, the effect of the induction heating on the surface of two mold plates was evaluated. Results showed that the heating speed decreased from 9.8 to 7.1°C/s when the coil pitch increases from 18 to 22 mm. For an initial mold temperature of 40°C, after 15 s heating, with the coil pitch of 18 mm, the temperature at the center of mold plate could approach to 147 °C. The temperature distribution on the mold surface was almost uniform with various coil pitches. The position of the coil has a slight effect on the distribution of the surface temperature. The areas near the inductor had a stronger heating effect than the center area of mold plate. The result of simulation and experiment showed good agreement.