Hybrid-laser welding combines the advantages of laser welding and gas metal arc welding to create an alternative welding process.
There is hardly a car being built today that doesn't have some sort of laser-welded part on it, whether it is laser-welded gear components or car keys. Laser welding offers a number of important advantages over more conventional welding technologies including speed and, more importantly, when it comes to welding thin sections, reduced distortion.
However, the technology does have one major downside in its ability to gap fill, which means that components being welded need to be fitted with close tolerances.
This can be solved with hybrid laser-arc welding, which combines the advantages of laser and arc welding, producing deep penetration welds comparable with laser welds yet at the same time having an improved tolerance to joint fit-up when compared with laser welding. In hybrid welding, any laser source (such as CO2 , Nd:YAG, diode, Yb fibre or Yb:YAG disk lasers) can, in theory, be combined with any arc source, such as MIG/MAG, TIG or plasma. In true hybrid welding, the two energy sources are usually combined so that the laser and arc operate in a single weld pool.
A wide range of materials can be hybrid welded, including C-Mn steels, stainless steels and aluminium alloys, and, less commonly, titanium and nickel alloys with typical joint configurations including butt and fillet welds.
In a dual process, the two separate weld processes act in succession, while in hybrid laser-welding both weld processes act simultaneously in a single process zone. The hybrid process improves process efficiency and overall productivity improves weld quality, lowers production costs and offers more versatility than conventional welding processes, setting new standards for productivity, cost efficiency and flexibility in heavy fabrication applications.
'Having worked with the laser hybrid process in different applications and in different base materials, we found that the process combines the best properties from both laser welding and MIG welding, often resulting in very good wetting,' says Lars-Erik Stridh, process application manager with ESAB.
He explains: 'When a bus manufacturer asked us if it was possible to improve the quality of a load-bearing part and the productivity of the welding process, laser-hybrid welding was the obvious choice for this material and application.' Another important effect of the process is that the welding speed is greatly increased compared to MIG welding, resulting in less heat input. Reduced heat input considerably reduces the risk of deforming the weld pieces, resulting in cost savings on work piece fixturing devices.'
The latest mechanised hybrid laser-arc welding process can use laser only, laser with cold wire fill, or hybrid laser arc welding in a 2D gantry, 3D robotic or custom systems with closed-loop process control.