“Through-arc” process monitoring: techniques for control of automated gas metal arc welding

Improved sensors are needed to enable automatic GMAW to accommodate a greater range of disturbing inputs. A low-cost, non-intrusive sensing technique, known as through-arc sensing, involves collecting and analyzing welding current and voltage signals. Through-arc sensing can be used to detect various GMAW quality indicators. It is shown that through-arc sensing can detect arc-start quality, steady-state arc stability, and the mode of metal transfer. Furthermore, the technique shows promise for detecting the onset of GMAW process disturbances including variations in tip-to-work distance, insufficient shielding gas coverage, electrode feeding problems, joint fit-up problems, and contact tip wear. Additional work is needed to refine and implement these techniques into a production-worthy system