SENSING FOR MONITORING OF THE LASER-GMAW HYBRID WELDING PROCESS

Laser-GMAW hybrid welding is an increasingly accepted technology for a variety of commercial applications, from industries as diverse as shipbuilding to automobile manufacture. As applications become more widespread, there will be a growing need to cost-effectively monitor the process in order to ensure consistent high quality. To address this growing need, a suite of sensors were used to monitor the laser-GMAW hybrid welding process, while intentionally introducing a variety of process perturbations. Process outputs that were monitored include the GMAW voltage and current, as well as the arc-plasma electromagnetic emissions in both the ultraviolet and infrared regions. Intentionally induced process perturbations included fluctuations in GMAW voltage and wire speed, laser angle of incidence, and laser/GMAW separation distance. The sensor data were collected, analyzed, and correlated with macroscopic evaluations of the weld bead geometry and heat-affected-zone. The data reveal a strong correlation between process variation and sensor readings, suggesting a quality control scheme for laser-GMAW hybrid welding that could rely on relatively inexpensive sensors.