Inline Repair of Blowouts During Laser Welding

Abstract

In a current laser welding production process of components of stainless steel, a butt joint configuration may lead to failures in the form of blowouts, causing an unacceptable welding quality. A study to improve the laser welding process was performed with the aim of solving the problem by designing a suitable pattern of multiple small laser spots rather than a single spot in the process zone.

The blowouts in the process are provoked by introducing small amounts of zinc powder in the butt joint. When the laser heats up the zinc, this rapidly evaporates and expands, leaving the melt pool to be blown away locally. Multiple spot pattern designs are tested. Spot patterns are produced by applying diffractive optics to a beam from a single mode fiber laser.

Results from welding while applying spot patterns both with and without trailing spots are presented. Data showing the power ratio between a trailing spot and two main spots as a function of spot distance is also presented.

The results of the study show that applying multiple spots in the welding process may improve the process stability when welding materials with small impurities in the form of zinc particles.