A comparative experimental study of laser fusion cutting of steel with 1 m and 10 m laser wavelengths

Abstract

This study aims to contribute to a better understanding of the cut surface quality difference between a laser with 1 µm wavelength (fiber or disc laser) and a 10.6 µm CO2 laser for laser fusion cutting of thick steel plates. Laser cutting of SUS304 stainless steel with thicknesses of 3, 5 and 8 mm was performed with a multimode fiber laser and a CO2 laser with the same power and comparative beam focusing characteristics. As already reported in the literature, the fiber laser exhibits worse surface quality for thicknesses with 5 and 8 mm. The result shows that the degradation of the surface roughness occurs when the cutting velocity becomes smaller than 1.5 m/min. We measured also the inclination angle α of the kerf front and it is shown that this range of cutting velocity corresponds to α < 3 degrees. This supports results of our analyses that stronger disturbance of melt flow or less absorption on kerf sides, which are induced by the small angle α, can be the reason for the laser wavelength dependence of the cut surface quality.This study aims to contribute to a better understanding of the cut surface quality difference between a laser with 1 µm wavelength (fiber or disc laser) and a 10.6 µm CO2 laser for laser fusion cutting of thick steel plates. Laser cutting of SUS304 stainless steel with thicknesses of 3, 5 and 8 mm was performed with a multimode fiber laser and a CO2 laser with the same power and comparative beam focusing characteristics. As already reported in the literature, the fiber laser exhibits worse surface quality for thicknesses with 5 and 8 mm. The result shows that the degradation of the surface roughness occurs when the cutting velocity becomes smaller than 1.5 m/min. We measured also the inclination angle α of the kerf front and it is shown that this range of cutting velocity corresponds to α < 3 degrees. This supports results of our analyses that stronger disturbance of melt flow or less absorption on kerf sides, which are induced by the small angle α, can be the reason for the laser wavelength dependence of...