Beam shaping to control of weldpool size in width and depth

The introduction of high power single mode fiber lasers has given deeper and narrower laser welds than seen previously. In some cases the weld becomes too narrow and must be expanded to fit the geometrical shape of a given weld task. It was suggested that instead of using only one beam, the beam was split into multiple beams placed in a pre-specified pattern. In this way the dimensions of the weld pool could be controlled. This gave the ability to control the final weld face width and penetration depth independently of each other with minimum heat input. Practical implementation of splitting a beam into a beam pattern with a diffractive optical element (DOE) is presented with results on splitting a beam from a single mode fiber laser into either three or seven individual beams on a row. Basic design rules for controlling the weld pool dimensions are developed. Results show that it is possible to control weldpool in size. (C) 2014 Published by Elsevier B.V.