A Port Injection Process for Improved Resin Delivery and Flow Control in Vacuum-Assisted Resin Transfer Molding

Abstract

Vacuum Assisted Resin Transfer Molding (VARTM) is used to produce high quality composite parts at lower cost than other manufacturing methods. However, traditional VARTM injection methods are incapable of accounting for variations in preform permeability within a mold. As a result, creating complex components is a labor intensive and expensive process often requiring a trial and error approach to insure complete infusion of the preform fibers. To address this limitation, a new system for delivering resin to a VARTM mold using a series of ports in the tooling surface rather than traditional injection lines has been developed. A port injection process has been designed that utilizes a closed loop control system of ports and sensors built into the mold. Finite element models of this new process indicate complete infusion can consistently be achieved, even for mold lay-ups with large variations in permeability. Results indicate the system is capable of identifying and accounting for preform variability, and correctly delivering resin to low permeability regions usually unfilled with conventional VARTM. In addition, this new technique significantly reduces lay-up time and total time to infuse a part. Experiments with a prototype lab-scale mold have been used to validate the performance of this new injection process. Unlike a conventional VARTM setup, the innovative port injection process can deliver resin to any location within the mold, thus reducing the potential for dry regions and improving part quality and consistency.