EXPERIMENTAL INVESTIGATION ON THE CUT FRONT GEOMETRY IN THE INERT GAS LASER FUSION CUTTING WITH DISK AND CO2 LASERS

摘要

In recent years, several studies on laser beam fusionrncutting demonstrated significant differences in therncharacteristics of the well-established CO_2 laser cuttingrnand cutting with solid-state disk and fibre lasers. Thernabsorptivity behaviour of metals shows essentialrnquantitative differences for the correspondingrnwavelengths of both laser sources as a function of therninclination angle between the laser beam and thernmaterial to be irradiated. In order to further thernunderstanding of the involved phenomena, a series ofrncutting experiments with CO_2 and disk lasers wasrncarried out. Similar geometry of CO_2 and disk laserrnbeam in terms of focus diameter and Rayleigh lengthrnwas used. In this work, the two dimensional stationaryrngeometric shape of the cutting front is acquired by thernlongitudinal sections of the cut specimen. The cuttingrnfront geometry and the corresponding local inclinationrnangle are related with the absorptivity calculated inrneach point of the cutting front. The effects of variousrnlaser processing parameters, as focal position andrncutting speed, on the geometric shape of the cuttingrnfront have been analyzed systematically on steel sheetrn5 and 8 mm thick.