Peak pulse power — The key to laser spot welding

The set-up and control of laser spot welding must be made more understandable if it is to reach its full potential in industry. Toward this end, a study was under-taken to better understand the variables that determine good-quality laser spot welds and the lasers to produce them. Peak power of the laser pulse was found to be the most influential parameter. For a particular optical spot size, it is the peak power that, once optimized, determines the weld quality. Focus-spot size can be held constant via fiber optic delivery so this variable is easily controlled. Software compensation to produce constant peak power during laser warm-up was found to allow 100% utilization of the laser. A laser with fiber delivery and warm-up compensation is the best system for spot welding.