Sensor system for monitoring impregnation and cure during resin transfer molding

Abstract In the resin transfer molding (RTM) fabrication of composites, knowledge of the position of a moving resin front during impregnation is important for process optimization. We describe here a simple, inexpensive, multi‐point sensor system based on DC conductometry for determination of resin position in an RTM mold. This Resin Position Sensor (RPS) system consists of a matrix of small sensors embedded in the RTM tool, whose combined output can be used to produce a resin flow pattern at any given time after the start of impregnation. As it cures, the resin resistance increases and the sensor can then function as a cure monitor. A large, 24‐sensor RTM tool was fabricated for demonstration of the RPS. Flow contour maps generated from sensor data during impregnation of both E‐glass and carbon fiber preforms are shown.