Real-time monitoring of high-power fibre-laser cutting for different types of materials

Abstract

Changes in gas pressure or cutting-head focus, as well as material warming can usually occur during metals processing, thus imposing insufficient quality of the resulting materials. These problems imply quality deterioration for both laser welding and laser cutting and cause the losses in terms of both time and cost. The primary aim of the present study is to solve these problems with special software. We discuss the effects of laser power, nozzle type, cutting speed and assisting-gas pressure on the quality characteristics of cut materials. Piercing and cutting processes are experimentally performed on the samples of stainless steel, aluminium and mild steel with the thicknesses 8, 12 and 20 mm, respectively. For each of these materials, we determine experimentally 'decision times' and analog-voltage thresholds corresponding to the material-surface temperature or the light intensity and then incorporate these parameters into the algorithm. The tests have demonstrated that our monitoring-based system is more successful than the standard metals-processing systems.