Influence of high frequency wobbling parameters on the weld quality of aluminium LBW

Currently available commercial remote laser beam welding (LBW) scanners allow a fast laser beam manipulation up to 1 KHz. In this work, wobbling (fast laser beam oscillation) was applied to weld aluminium alloy (5754) sheets of 1.6 mm thickness that are subjected to stamping processes later on. Influence of process parameters (laser power and speed, incidence angle and wobbling frequency and amplitude) in weld quality of T joint and edge lap joint configurations was studied. In T joint configuration, the use of 4047 wire filler metal of 1.2 mm of diameter was beneficial to avoid excessive undercuts and provide good penetration, weld shape and dimensions. Metallographic characterisation confirmed the absence of other defects such as lack of fusion, pores or cracks. In addition, wobbling led to optimal results without removing the protective coating of Ti/Zr from the sheets. Finally, mechanical characterisation for post-welding stamping suitability assessment of the welds was performed using shear and bending tests.