Enabling electrical functionality of carbon fibre composites via tow steering during additive manufacturing

Additive manufacturing of carbon fibre reinforced polymer composites enables the steering of individual fibre tows. This design flexibility has been successfully used to optimise carbon fibre composites for mechanical loading, but limited work has been carried out investigating how it could be used to enable processes that rely on the electrical properties. In this study, several carbon fibre samples are additively manufactured, and their induction heating behaviour is measured. The results indicate that a concentric layup pattern, made possible by tow steering, increases the maximum temperature reached by over 260%, compared to equivalent additively manufactured laminates with a traditional quasi-isotropic layup pattern. This demonstrates that tow steering of continuous carbon fibre can be used to alter electrical behaviour and enable new functionality. Induction welding is then used to demonstrate a practical application of this ability. Several additively manufactured samples are designed with their main structure consisting of unidirectional fibres for strength, and the joining area of the samples manufactured using a concentric pattern with improved inductance. The samples are then joined by induction welding. The results show that tow steering enables the manufacture of composite structures with one area designed for strength and another area designed to enable induction heating.