Optical sensor for real-time monitoring of CO2 laser welding process

An optical sensor for real-time monitoring of laser welding based on a spec troscopic study of the optical emission of plasma plumes has been developed . The welding plasma's electron temperature was contemporarily monitored fo r three of the chemical species that constitute the plasma plume by use of related emission lines. The evolution of electron temperature was recorded and analyzed during several welding procedures carried out under various op erating conditions. A clear correlation between the mean value and the stan dard deviation of the plasma's electron temperature and the quality of the welded joint has been found. We used this information to find optimal weldi ng parameters and for real-time detection of weld defects such as crater fo rmation, lack of penetration, weld disruptions, and seam oxidation. (C) 200 1 Optical Society of America.