Flow Monitoring and Permeability Measurements in LCM Processes by the means of a Dielectric Sensor

Liquid Composite Molding (LCM) processes are manufacturing techniques characterized by the impregnation of a dry fibrous preform, by the means of injection or infusion of a catalyzed resin system. Although computational modelling and simulation have led to a better understanding and more effective planning of LCM processes, on line monitoring of resin flow is very desirable to detect variations of processing conditions. Moreover, an accurate experimental evaluation of fiber preform properties is crucial for a reliable process simulation. In this paper, a dielectric capacitive system has been designed and applied to monitor the position of the saturated as well as the unsaturated flow fronts and to evaluate in plane bulk permeability and tow permeability of dual scale fibrous porous media. The sensors, analysed and optimized by computational simulations, have been used in one-dimensional flow tests. Good agreement has been found between results provided by the considered system and data obtained through conventional techniques, highlighting the potential capabilities of proposed method.