Frequently Asked Questions
Laser welding is being considered by many in the aerospace sector as an alternative to mechanical fastening and adhesive bonding for applications in fuselage and wing fabrication. Improvements in quality, cost and weight saving are expected by simplification of the manufacturing process. One such application involves the strengthening of skin panels by the addition of welded stiffeners or stringers.
The 2XXX series and 7XXX series aluminium alloys are widely used in the manufacture of aircraft components. Both these alloys are difficult to weld with lasers due to their propensity for porosity and solidification cracking. However, by correct choice of filler wire material and laser beam parameters, it is possible to eliminate cracking and reduce porosity to a minimum when welding these alloys.
Figure 1 shows a typical demonstration stiffened panel manufactured from AA2014 alloy in the T4 condition. The base is 3mm thick and the stringers are 3.5mm thick. ER 2319 filler wire was used, and the stringers were welded using a Nd:YAG laser beam, delivered by fibre optics, at a power of about 3.5kW. The welding speed was 2m/min. Figure 2 shows a cross-section of a two-pass weld, typical of those made on the panel shown in Fig.1.
CO2 laser welding of AA6013 plates and stiffeners has recently been qualified for production by Daimler Chrysler Aerospace Airbus, and other aircraft manufacturers are actively considering the use of laser beam welding for fuselage components.
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Fig.1. Demonstration stiffened panel in 2014 alloy
Fig.2. Section of a two-pass laser weld in 2014 alloy, typical of those made on the panel shown in Fig.1