A simplified voltage model in GMAW

The relation between the voltage and the arc length in gas metal arc welding (GMAW) is an important characteristic. It depends on a complex distribution of the electric conductivity along the current path and does not depend on the arc length only. Based on electric measurements and the arc length determination from high-speed arc images, a simplified electrical model is introduced for a pulsed GMAW process. It shows the relation of voltage, current, arc length and free wire length and considers also their temporal evolution during the process in particular during the high-current phase. Previous detailed studies of the sheath voltage and the resistances in the contact tube, the free wire, the droplet depot and the arc in pulsed processes with changing arc lengths have been used. The electrical model shows a sufficient agreement with measurements also for parameter ranges of the wire feed speed and the contact-to-workpiece-distance (CTWD) which have not been considered in the model deduction. This data set includes the model parameters, examples of arc images, measurements of voltage, current and arc length as well as model predictions for voltage and arc length in comparison with the measurements.