Welding aluminum sheet using a high-power diode laser

The feasibility has been studied of producing fillet welds in lap joints in Alloy 5182 aluminum sheet with a high-power diode laser. Laser energy absorption and bead formation were found to be very sensitive to surface conditions. Sanding and cleaning of workpieces reduced the weld area significantly compared to as-received sheet surface conditions. Cleaning, however, reduced oxide tail defects and consistently produced welds with increased throat. The addition of dark substances to the surface of the sheets was shown to increase absorptivity, although not necessarily increasing the weld throat. Effects of laser beam presentation were studied, and operating ranges were defined. Mechanisms of pool development in fillet welds in lap joints were explored. It was found that production of fillet welds lap joints in aluminum sheet with the diode laser is feasible for industrial use and may be especially useful for welding of hem joints in automotive closure panels.