Sequential multiple port injection for resin transfer molding of polymer composites

The resin transfer molding (RTM) technique offers the potential for low cost and fast processing of polymer composite parts and structures. A multiple port resin injection scheme is proposed for enhancing mold filling times. The ports are opened in sequence during RTM. Numerical studies were used to illustrate the application of the concept in RTM. The simulations were based on a model for resin impregnation of non-woven bi-directional fabrics, with global resin flow along one spatial direction. Results from the numerical studies suggest a strategy of injecting resin behind the global flow front, while maintaining a vacuum on the mold cavity to minimize voids. This scheme allows a regain in resin pressure, and hence resin flow rate, without an associated increase in void content. The simulation results also provide insights on the relationships between RTM variables