Ultrasonic Resin Impregnation Monitoring in Fixed Double Rollers Press Molding of FRP

In this study, the ultrasonic resin impregnation monitoring method developed in our laboratory for RTM molding was applied to fixed double roller press molding, and its effectiveness was verified. In order to form a pipe-shaped FRP, reinforcing fibers are placed between the outer bag and inner bag, and the liquid resin is filled into reinforcing fiber layer. Then that is pressed by a fixed double roller to impregnate resin. The results of the resin impregnation monitoring showed that ultrasonic waves reflected from the surface of the inner bag can be detected, and the intensity of that wave could be used as resin impregnation index. Micrograph observation of the molded plates revealed that resin impregnation mainly proceeds in the thickness direction of FRP pipes in the fixed roller press molding. In addition, it was found that increasing the number of roller presses lead to better resin impregnation state.