Unsaturated polyester/E-glass fiber composites made by vacuum assisted compression resin transfer molding

A variant process incorporating the method of bag compression into resin transfer molding (RTM), called vacuum assisted compression RTM ( VACRTM), has been developed to reduce the cycling period and improve the quality of the part. The process utilizes a flexible bag placed between the upper mold and the preform compared with RTM. By controlling the stretchable bag, the resin is easily introduced into the cavity filled with a loose preform. Then, ambient pressure is applied on the bag that compacts the preform and drives the resin through the remaining dry preform. The objective of this research is to explore the simplified VACRTM feasibility and investigate the effects of process variables, including resin temperature, resin infusion pressure, mold cavity height and cure temperature, on the mechanical strength of the part, by applying Taguchi's method. The results show that VACRTM has advantages in terms of its being an easy and good seal among mold parts and the the lack of a need to clean the upper mold. The resin infusion pressure is a significant variable for improvement of the mechanical strength of the part. Optimal VACRTM reduces the filling time by 58% and increases the flexural strength by 10%, as compared with typical vacuum assisted RTM (VARTM).