Robust technique for spectroscopic plasma analysis with application in real-time arc welding quality monitoring

Abstract

A new real-time implementation of the Boltzmann-plot technique for optical spectroscopic analysis of thermal plasmas is presented. Applications are found in the monitoring of industrial processes in which plasma emission naturally occurs, such as arc and laser welding. Experimental results show the feasibility of using the Boltzmann-plot technique for real-time calculation of the electronic temperature of the plasma, a parameter that has been correlated with common defects found in the weld seam. The foundations of the proposed technique, its implementation, and its capability for the on-line detection of defects in tungsten inert gas TIG welding of steel parts are discussed.