Enabling Automated Joining: Advances in Robotic Continuous Ultrasonic Welding of Thermoplastic Composites

acm7 Tracking Number 33

Thermoplastic composites offer high weight-specific properties and can be reprocessed with heat, enabling repairability, out-of-autoclave processing and joining. Continuous Ultrasonic Welding (CUW) is an especially fast and efficient thermoplastic joining process. However, achieving consistent and defect-free robotic CUW welds remains a challenge, in part due to the high forces being applied which deflect the robot and CUW end-effector. These deflections, especially tilt errors, negatively affect weld quality. Building on previous work that characterized repeatable tilt errors during welding motion, this research integrates a laser line scanner to provide real-time feedback on the sonotrode orientation relative to the welding adherends. The laser line scanner measures the angle between the sonotrode and the adherends, enabling active compensation for tilt deviations caused by frictional and welding process forces. This work improves the reliability in automated CUW of thermoplastic composites, improving weld quality while removing the need for manual calibration work which helps industrialize the technique.