Additively Manufactured Low-Cost Resin Transfer Molding Tooling with Embedded Flow Monitoring Sensors to Manufacture High-Performance Composites

Resin Transfer Molding (RTM) is a process in which a thermoset polymer is injected into a closed mold filled with dry fabric reinforcement. Achieving net-shaped, void-free composite parts in RTM depends on using well-designed molds that promote uniform resin flow throughout the fiber preform. Traditionally, the design and fabrication of RTM molds, including the placement of injection gates and vent channels, involves an expensive and iterative process. This study investigates the integration of additive manufacturing (AM) techniques for the rapid prototyping of RTM molds with embedded sensing capabilities for real-time monitoring of the resin infusion process. In this work, carbon nanotube (CNT)-coated veils are incorporated as in-situ sensors within the AM-fabricated molds. The electrical conductivity of veils changes in response to resin infiltration, allowing for the detection of resin arrival and saturation at predefined locations within the mold. Experimental sensor data acquired during RTM trials are systematically compared with numerical predictions from resin flow simulations. Results show that the sensor signals provide local measurements of resin arrival times, supporting the feasibility of AM-enabled, sensor-integrated molds for RTM process monitoring and potential real-time control.