These slides were presented at the NAFEMS World Congress 2025, held in Salzburg, Austria from May 19–22, 2025.

Abstract

Many plastic connector housings are manufactured through the injection molding process because the process is fast and consistent, enabling high volume production. For large housing parts, the cooling step of the molding process can be very long. In order to increase productivity, it is desirable to reduce the cooling time using technologies such as mold inserts with conformal cooling channels and high thermal conductivity mold inserts. Conformal cooling channels are cooling channels which conform to the shape of the mold cavity. Compared to traditional straight cooling channels, the distance between the coolant in conformal cooling channels and the plastic melt is reduced, thus enabling more efficient heat transfer and faster cooling. High thermal conductivity mold inserts typically consists of core made with a good thermal conductor such as copper and a steel shell to provide strength. They are suitable for the cooling of parts with complex geometries that are difficult to cool with traditional or conformal cooling channels. These mold inserts are usually fabricated using additive manufacturing methods, so their fabrication comes at a cost. The benefit of shorter cooling time needs to be balanced against the extra cost of producing the mold insert and its expected life. In this study, a simulation workflow to evaluate the cooling strategy in the injection molding process is discussed. A case study involving high thermal conductivity mold inserts is presented. Injection molding simulations are used to determine the cooling time reduction that can be achieved using the mold inserts. Subsequently, the pressure and temperature loads are exported from the molding simulations to be used in a fatigue analysis to estimate the expected mold insert life. A cost-benefit analysis can then be carried out for the molding process. The workflow can help to determine the optimum cooling strategy for the injection molding process of different plastic parts.