This study aims to establish a continuous ultrasonic welding process for thermoplastic CFRP components by joining pultruded square rods, fabricated from thermoplastic CFRP prepreg tape, with thermoplastic CFRP laminates. To achieve this, we developed a novel ultrasonic continuous welding system consisting of a servo press unit with precise control of load and displacement, a 20 kHz ultrasonic heating unit, and a pressure-cooling unit. Welding experiments were conducted by varying key process parameters such as the traveling speed of the ultrasonic horn and the control method of ultrasonic oscillation. The influence of these parameters on the welding behavior and joint strength was experimentally investigated. As a result, we successfully clarified the relationship between welding conditions and welding performance, contributing to a better understanding of the process for high-speed, reliable joining of thermoplastic composites. The developed system demonstrates the feasibility of scalable, continuous ultrasonic welding for structural CFRP applications.
Hashimoto et al. (2025) studied this question.