Optical emissions from weld arcs and their effects on the performance of welding robot vision systems

Abstract

The design and operation of one-pass arc welding robot vision systems are greatly complicated by the presence of the bright weld arc and the harsh welding environment. In this paper we present absolute intensity measurements of weld arc spectra at visible and near-IR wavelengths using Ar–O2 shield gas with solid wire and CO2 shield gas with flux-core wire. These measurements reveal the existence of many strong emission lines in the weld arc spectrum. The intense arc interference can be avoided by appropriately choosing the operating wavelength and by using a narrowband interference filter to prevent most of the arc radiation from reaching the detector of the vision system camera.