Undercut suppression in laser-arc hybrid welding by melt pool tailoring

In welding, high welding speeds are usually limited by an increase in undercut. This study shows that the geometrical conditions of the melt flow can be tailored to suppress undercut when using the arc leading setup. By applying high speed imaging, it can be seen that the keyhole and its position affects the melt flow, making the distance between the laser and the arc an important parameter. Undercut formation usually occurs due to a narrowing or necking of the melt flow behind the gouge that can be prevented if the melt flow is changed by optimizing the laser/arc positioning. (C) 2014 Laser Institute of America.