In-Mold Electronics (IME) is a manufacturing method that integrates printed decorations and electronic circuitry with thermoforming and injection molding processes. The method enables the production of ergonomic, lightweight and durable parts through cost-effective processes that require less assembly. Herein, the effect of circuit shape on line-width change by thermoforming was investigated through experiments and analysis based on the K-BKZ nonlinear viscoelastic model. Two circuit shapes, a horseshoe and a coil, were proposed and their line widths after thermoforming were measured and compared to that of a straight line shape. In the horseshoe-shaped circuit, the line width decreased as the radius increased due to the influence of vertical stretching caused by thermoforming. However, the effect of the angle on the line width was insignificant. In the coil-shaped circuit, the width of the line decreased as the pitch increased. However, as the amplitude increased, the line width also increased, but the effect was not significant. For the circuit shapes of the straight line, horseshoe and coil shapes, the rate of change in line width was 4.4, 0.4, and 0.2%, respectively. After conducting research, it was found that the coil-shaped circuit is more effective in minimizing line-width change caused by film thermoforming.

The design of the injection mold cooling system is important. The cooling time consumes 70-80% of the injection molding cycle, so a well-designed cooling system can shorten the molding time and improve productivity significantly. Recently, many studies have been conducted for rapid cooling of a hot-spot area using CO₂ in injection molding. In this study, a cooling module based on CO₂ was designed and manufactured for uniform and rapid cooling of an injection mold with a large cavity, and cooling characteristics were investigated through experiments. As the CO₂ supply pressure increased, the cooling effect increased significantly, while the cooling uniformity decreased relatively. In the case of using the heat exchanger, the cooling effect increased by 10oC on average compared to the case without the heat exchanger, whereas the effect on the cooling uniformity was insignificant. When the CO₂ was injected from both sides, the cooling effect increased by approximately 8oC on average compared to the case of injection from one side, and the cooling uniformity was approximately 10% higher. By using a heat exchanger and applying CO₂ bidirectional supply, a cooling rate of up to 5.78℃/s and an average of 4.9℃/s could be achieved.

In-mold coating is a reactive fluid designed to improve the surface quality of injection molded thermoplastic substrate in functional and cosmetic properties. In this study, a mixing head for inmold coating was designed, and mixing characteristics of two-component polyurethane flowing through runner were investigated based on flow simulations. In order to achieve uniform mixing of two components injected through straight mixing head, an impingement aftermixer was used in runner design. Semi-circular cross-section was better than circular one for runners for uniform mixing. With increasing runner length and flow rate, mixing became more uniform. In addition, the degree of mixing was more improved with decreasing viscosity of isocyanate.