Preparation of carbon fiber heating elements and their effects on the properties of resistance welding joints in thermoplastic composite materials

This paper presents the preparation of two types of thin-layer carbon fiber stretched-width cloth heating elements using the suspension impregnation process with polyether-ether-ketone (PEEK) powder and the melt impregnation process with PEEK resin film. The resistance welding technology for carbon fiber reinforced polyether-ether-ketone composite laminates was experimentally investigated. The results demonstrated that employing an “embedded type” electrode arrangement effectively mitigates the “edge effect” caused by exposed heating elements during resistance welding. Moreover, it was found that the heating time significantly influences the strength of welded joints, which initially increases and then decreases, reaching a maximum value of 28.1 MPa at 120 s. Additionally, the fracture failure mode has changed from initial adhesive failure to a mixed failure mode of implant and fiber. Furthermore, compared to melt impregnation, powder suspension impregnation process enhance joint strength by 15% under identical welding conditions.