Multiple Injection Ports and Part Thickness Impact on Wetout of High Pull Speed Resin Injection Pultrusion

Abstract

Manufacturing of composite materials using resin injection pultrusion is presently a cost-effective method of producing composites; however, there is still a potential for significant improvements in the productivity of this approach for high-speed production. Complete wetout of the dry fiber reinforcement by the liquid resin at high pull speeds is essential for improving the throughput of the pultrusion process. Complete fiber reinforcement wetout depends strongly on axial placement of the injection ports/slots and the geometry of the injection chamber (taper of the walls of injection chamber and final part thickness). Geometric parameters modeled in this study were multiple injection ports and their axial location within the injection chamber and thickness of the final pultruded part; investigations of these geometric parameters are original contributions of the work. In this study, the finite volume numerical technique was employed to model the flow of polyester resin through the glass fiber reinforcement. Results depict the impact of varying the thickness of the pultruded part and the use of multiple injection ports on the minimum injection pressure necessary to achieve complete fiber matrix wetout and on the resin pressure at the injection chamber exit for the slot injection and for the discrete port injection configurations. This model is a useful guide for improving the efficiency and productivity of the resin injection pultrusion process for an attached injection chamber configuration with tapered walls.