With the advancement of high power fiber-delivery lasers, remote laser welding becomes a reality and more and more systems have been introduced into production lines. Remote laser welding takes the advantages of less mechanical movement and better accessibility of the beam to the workpiece, thus fast processing speed can be achieved. In most cases, remote laser welding involves lap welding. Laser beam lap welding of zinc coated steel components is not a straightforward process and it requires a special procedure to provide proper venting for the zinc vapour which is generated during welding in the interface. Although there are many approaches to address this issue, many of the approaches are either impractical or too costly to apply to remote laser beam welding in production.
Humping effect is an adverse effect that limits the achievable welding speed in laser beam welding. However, it has been demonstrated in the experiment that the height of the protuberance in the humping effect can be controlled via proper process parameters and an optimal height in the range of 0.1 – 0.2 mm can be achieved to meet vapour venting requirement. In reality, the optimum gap size is depending on material thickness and coating type. As a result, the high-speed humping effect can be advantageously used as a pre-process to provide proper gap for laser beam lap welding of zinc coated sheet metals. Furthermore, this pre-process can be naturally implemented in the remote laser welding process flow. The whole process is very flexible and can be achieved at very high speed.