Filling Time Reduction in Liquid Composite Molding Processes

Abstract The quality of Liquid Composite Molding (LCM) manufactured components is strictly related to the fibrous preform impregnation. As Darcy’s law suggests, the resin flow is influenced by the pressure gradient, geometrical features of the reinforcement, and resin viscosity. The former two parameters are dictated by the requirements of the component and other constraints; therefore, they are hardly modifiable during the process. Resin preheating increases its fluency, thus enhancing the impregnation and saturation flow, and reducing the mold filling time. In the present work, a microwave heating system has been integrated within a vacuum bag resin infusion process, to analyze the effect of the online preheating on the fiber impregnation. To monitor the resin flow a dielectric sensors-based system is used. Results from resin infusion tests conducted with and without the resin pre-heating were compared: the outcomes indicated an advance of approximately 190 s of the flow front when microwave heating is applied with respect to the unheated tests.