Characterisation of figure-eight shaped oscillation laser welding behaviour of 5083 aluminium alloy

Figure-eight shaped oscillation movement of laser was studied to improve the welding quality of 5-mm-thick 5083 aluminium alloy. The tests were conducted at 3 kW laser power for frequency levels ranging from 25 to 125 Hz and focal point positions as 0, -1 and -2 mm. The quality of welds was characterised by non-destructive testing methods including visual, liquid penetrant and radiographic inspections. In addition, mechanical properties were determined by tensile tests and microstructures were examined by digital video camera and optical microscope. The results showed that welds with lower penetration depth and less porous structure could be obtained at 125 Hz frequency independent of the focal point position when compared to the joints produced without beam oscillation.