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

Abstract

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.

Influence of Beam Figure on Porosity of Electron Beam Welded Thin-Walled Aluminum Plates

“…Using a narrower figure with the intention to produce a narrower weld in order to provide less space for pores to be formed did not prove to be effective. This finding is contradictory to the ones reported by Chen et al [ 14 ]: in their study, the narrowest amplitude (0.7 mm) also had the lowest porosity (14%). However, the narrowest amplitude from Chen et al [ 14 ] was 1.5 larger than the standard amplitude of 0.45 mm used in this study.…”

“…This finding is contradictory to the ones reported by Chen et al [ 14 ]: in their study, the narrowest amplitude (0.7 mm) also had the lowest porosity (14%). However, the narrowest amplitude from Chen et al [ 14 ] was 1.5 larger than the standard amplitude of 0.45 mm used in this study. In the aforementioned studies, welds with different parameters and beam oscillations were investigated, but this was limited to one weld per parameter set, which was never longer than 200 mm.…”

“…It is evident that the resulting energy fields can promote the outgassing of bubbles. Similar results regarding beam deflection and porosity were also shown by Kabasakaloglu et al [ 13 ] and Chen et al [ 14 ] in their investigation of laser welding, although they only considered one figure (“8” & “∞”). However, by varying different welding parameters, such as focus and frequency, they also presented different modes of energy input.…”

“…Kabasakaloglu et al [ 13 ] and Chen et al [ 14 ] showed that frequency affects both porosity and seam geometry. Both studies showed that with higher frequency, the ratio of weld-width to -depth became less.…”

“…In the case of superimposed oscillations, the shape of the “eight” appears in the literature, in addition to the circle; both represent so-called Lissajous figures. Kabasakaloglu et al [ 13 ] and Chen et al [ 14 ] investigated the influences of the beam deflection on the porosity. In both studies the figure of the “eight”, either standing (8) or lying (∞) was selected.…”