STTR Phase I: Laser Ultrasonic Emission Sensor for In-process Monitoring during High-Speed Laser Welding

The Small Business Technology Transfer Research (STTR) Phase I project will demonstrate the technical feasibility for in-process monitoring of welding quality during high-speed laser welding of thin plates which is critical to manufacturing of fuel cells. The monitoring system is based on laser detection of small ultrasonic signals emitted during the welding process. The proposed technique is a modification of laser-based ultrasonic inspection. In this technique, the high-speed laser welding process is used as the ultrasonic source and a laser interferometer is used to continuously monitor the ultrasonic emission generated at the weld pool and to assess the weld quality. The proposed in-process laser welding monitoring technique is critical for the manufacturing of commercial hydrogen fuel cells to be used in the next generation of energy efficient transportation vehicles. The new in-process monitoring technique will allow to monitor weld quality in real-time, suppressing the need for post-process inspection. Other industries where laser welding of thin parts is intensively used, such as the pharmaceutical industry, could benefit from the proposed in-process sensor.