K. Alqosaibi, C. Thakur, A.A. Duhduh, J.P. Coulter
Keywords: injection molding, hot runner system, polymer processing
Summary:This paper describes current efforts to investigate and resolve the cold slug formation issue that occurs during the injection molding cycle of hot runner systems. This issue occurs between injection molding cycles at the nozzle tip due to high viscosity associated with lower temperatures. It affects the quality of the final molded parts by blocking smaller mold cavity passages and causing incomplete cavity filling. A hybrid hot runner system was developed in order to solve this problem. The main goal of this system is to prevent the cold slug formation by manipulating the viscosity of the polymer melt inside the runners. The viscosity of the melt is tuned by controlling shear rate using the novel hybrid hot runner system. In this study, the hybrid hot runner system is proposed. Also, numerical simulations through ANSYS Fluent were conducted to simulate the polymer flow in the runner and to validate the novel concept.