RESISTANCE HEATING OF CARBON FIBER REINFORCED THERMOPLASTICS-INFLUENCES ON HEATING RATE AND TEMPERATURE DISTRIBUTION

摘要

Continuous fiber reinforced thermoplastics (CFRTP) experience increasing demand by industry.Compared to their thermoset counterpart,they are considered to allow for shorter production cycles and offer more and better joining and recycling solutions.Usually,continuous fiber reinforced semi-finished parts are produced and then prepared for a back injection molding process to add functional integration.The resistance or joule heating process utilizes the electrical conductivity and accompanying heat dissipation of embedded carbon fibers.Thus,a short and homogenous heating process can be achieved.The main challenges that arise with resistance heating are the optimization of the electrical contact pieces as well as the shape and build of the semi-finished part.The heating process of several variations of contact pieces and shapes are monitored using thermal imaging.An algorithm is developed to automatically analyze key aspects of the heating process allowing for easy comparison of different parameter sets.Key results show that rounded edges for copper contact pieces and high contact forces yield homogenous temperature distributions and prevent hot spots while higher voltages result in less homogenous temperature distributions but higher heating rates.