Real time torch height detection technique for gas metal arc CO₂ welding

Abstract

This paper describes results achieved in the development of a new type of welding torch position sensor, which enables real time measurement of the torch–workpiece distance in gas metal arc welding with shortcircuiting metal transfer. The sensor is based on a detection algorithm which enables extraction of the torch–workpiece distance from welding current and voltage waveforms, regardless of large variations in the instantaneous values of welding parameters. It was found that the torch–workpiece distance could be reliably obtained from wire resistance data during a shortcircuit state of the welding process. The sensor was tested under various welding conditions and its applicability was confirmed by real time monitoring of the sensor signal.