Analysis of arc voltage, current, and light signals in pulsed gas metal arc welding of aluminium

The use of readily acquired weld arc data such as voltage, current, or ligh t emissions to identify droplet transfer events or transfer mode, or for qu ality purposes such as seam tracking is of interest for thin section applic ations in arc welding of aluminium. In the present study, voltage, current, and light emission signals are acquired at high rates, and synchronised wi th high speed shadowgraphing. The usefulness of the various signals for ide ntifying droplet detachment events and transfer modes during pulsed gas met al are welding of aluminium is compared. It is found that individual drople t detachments ale consistently identifiable during globular, spray, and str eaming transfer, and during peak and background current detachment using th e voltage signal. Although the are light signal also contains droplet detac hment data, it is difficult to identify droplet detachments occurring durin g the background phase at low background curl ent levels. Preliminary measu rements show that these signals can also be used for seam location in thin section lap fillet welding.