Difference between arc welding and laser welding

The Arc and the Molten Pool

In traditional welding processes, heat is generated by the arc that burns between the workpiece and a (melting) electrode or wire. The size of the molten pool is largely determined by the dimensions of the spot where the arc contacts the base material. Compared to laser welding, this molten pool is much larger. This has the advantage that it can bridge larger gaps, as the liquid welding metal nicely fills the gap. On the other hand, this larger molten pool also has the disadvantage that it requires a lot of energy. Material distortion is often quite visible as a result. This can be significant, especially for stainless steel products. Additionally, the discoloration of the material will be considerably more pronounced in the case of stainless steel. Due to the longer duration and the larger molten pool, there is more opportunity for oxygen to react with the liquid welding metal or hot base material.

Compared to traditional welding processes, learning laser welding is straightforward. Since the welding gun is usually pulled in a straight line along the seam, it is mainly important for the welder to develop a good sense of the correct welding speed.

Welding with Filler Material

In traditional welding processes, a significantly larger amount of welding metal can be added. Creating fillet welds with a high leg length can be excellently accomplished with MIG/MAG welding or TIG welding.

In laser welding as well, it is possible to weld with filler material. In most cases, this addition is used to ensure that the weld appearance meets the standards. A small gap can be more easily welded with a laser when filler material is used.

In the laser welding process, the molten pool is created by focusing very high energy on a small point on the material. The size of the molten pool is not much larger than the laser spot. Since this can result in a molten pool that is too small, there is the possibility to rapidly rotate or oscillate the laser spot. This movement is often referred to as “wobble.” The wobble is adjustable on the welding gun, both in terms of shape (rotation/oscillation) and width. The use of a welding gun with wobble has made it easier to apply manual laser welding.