Just one set of standard copper electrodes produced 50,000 high-quality welds on automotive-grade aluminum sheet. The feat was an outcome of resistance spot-welding research by Paul Briskham at the University of Warwick and Douglas Boomer of Innoval Technology, along with engineers from Jaguar and Land Rover.
The remarkably long electrode life resulted from polishing the copper electrodes during the brief gap in time between welded components. Resistance spot welding is the most widely used process for joining steel sheet in the automotive industry, largely because it is economical for high volumes and excellent for pulling together components prior to welding. A major hurdle to adopting the process for aluminum automotive sheet, however, has been short electrode life and corresponding loss of weld quality.
Previous studies have shown that electrode life can be extended to a few thousand welds by regular tip dressing using form cutters commonly used to maintain electrodes when welding galvanized or high-strength steels. This study showed significant improvement in electrode life from using a system that polishes electrodes with an abrasive wheel to maintain a domed profile.