Introducing a Novel Infrared-Thermography-Based Control Method for Continuous Ultrasonic Welding of CFRPs

Ultrasonic welding of carbon-fibre-reinforced polymers delivers fast, high-quality joints and scales well to automated, high-rate production. In continuous welding, the progressing weld seam constantly changes the boundary conditions, especially in respect to ultrasonic welding. For this reason, it is particularly important for applications in the aerospace sector that the continuous ultrasonic welding process is actively controlled, especially when a thorough and robust weld seam quality is required. This short communication introduces a novel control method where material feedback (temperature) is incorporated as a reference variable by using an infrared thermography camera as a feedback sensor in a closed-loop controller. Furthermore, this study presents preliminary results, such as improved process robustness and repeatability compared with conventional process control methods, such as constant-amplitude or constant-power control. These results were evaluated using destructive and non-destructive testing methods and form the basis for further, in-depth analyses in future experiments.