Precleaning and spot welding of an automotive body steel using a Nd:Yag laser

Abstract

Whilst coating automotive body steels with zinc has a beneficial effect on their corrosion properties it can give significant problems when individual panels are subsequently welded to form the body shell. This work shows that a pulsed Nd:Yag laser can be used as a precleaning tool to locally remove the zinc and then as a spot welding device to join 2 sheets in a lap weld configuration. Laser spot welding can produce joints having adequate strength at a range of conditions but the localised nature of the heat input can produce damage on the top surface, this is often not acceptable in structures such as a an automotive body shell. In this work, conditions have been identified which are capable of precleaning the area to be welded and able to produce welds having adequate strength with cosmetically acceptable surfaces