High speed welding of aluminium alloy sheets using laser assisted alternating current pulsed metal inert gas process

Abstract

Abstract Alternating current pulsed metal inert gas welding is an appropriate process for joining aluminium alloy sheets because of its great gap tolerance and low heat input, which assists in avoiding burn through. However, when welding speed is higher than 2 m min-1 the low heat input is no longer an advantage since lack of penetration becomes a problem. Irradiation of the vicinity of the arc using a laser beam can solve this problem, and adjustment of the laser power can control the penetration. As a result, thin aluminium alloy sheets can be joined at a high speed of 4 m min-1 with sufficient gap tolerance. Moreover, investigation of the effect of laser beam diameter on the resulting weld for thin sheets indicates that a defocused laser beam having a diameter of several millimetres can further improve the ability to bridge joint gaps and tolerance of deviations in torch aim. Consequently, a high power diode laser having a relatively thick beam waist is suitable for this application.