An Energy Efficient Injection Molding Process Based on Dynamic Thermal Equilibrium Within the Mold Cavity

ABSTRACT In injection molding, maintaining the mold temperature needs large energy consumption. In fact, heat carried by melt can enable mold temperature to reach a dynamic thermal equilibrium. Induction heating was introduced to realize the thermal equilibrium, which provides an initial condition with low energy consumption and ensures effective filling of the mold cavity during the balancing process. Through theoretical simplification, a finite element analysis model is developed, which accurately captures the mold temperature field evolution during thermal balancing. This model is validated using injection molding experiments, power measurements, and product characterization tests. Simulation results indicate that the mold surface undergoes multiple distinct stages during continuous injection molding before reaching thermal equilibrium. The rationality of the finite element model and the feasibility of the new process were confirmed through comparison between simulated and experimental temperature data. The final equilibrium temperature can be determined by the base mold temperature, induction heating temperature, and cooling time. Energy consumption analysis demonstrated that the new process saves a maximum of 41.11% energy consumption compared to the conventional constant‐temperature process at a mold temperature of 75°C. The characterization results of crystallinity and glossiness of parts have verified the feasibility of the new process. In conclusion, this study offers a promising solution for energy conservation in the injection molding industry.