Sensors on a plasticized thermoset substrate for cure monitoring of CFRP production

Embedding sensors for in-situ monitoring of composite manufacturing guarantees high quality and cost-optimized products. For minimally invasive sensor integration, the ideal sensors should be made of identical material of the final host product. Frequently, thermoset resins are used for high-performance fibre reinforced composite in aerospace and automotive industries. A thin layer of cured thermoset resin is rigid and brittle and it cannot be reshaped. Thus, it cannot afford to be the substrate of a sensor if flexibility is required. By adding a plasticizer to the resin, a flexible substrate is produced. The substrate is tested to produce a sensor by using a hollow mask to screen-print interdigital structures. This sensor is used to measure the curing of resin during production of Carbon Fibre Reinforced Polymers (CFRP), known to be electrically conductive. Mechanical tests show a better adhesion of the developed substrate to the host structure compared with commonly used polyimide.