A comparative study on fusion cutting with disk and CO2 lasers

In recent years, several studies on laser beam fusion cutting demonstrated significant differences in the characteristics of the well-established CO2 laser cutting and cutting with solid-state disk and fiber lasers. The reasons for the observed differences in cutting efficiency and cut edge quality are still the subject of the current research and not finally clarified. In order to further the understanding of the involved phenomena, a series of cutting experiments with CO2 and disk lasers was carried out using a Design of Experiment (DoE) approach. The particular feature of the applied experimental setup was the similar geometry of both the CO2 and the disk laser beam with comparable values of the focus diameter and the Rayleigh length. Cutting trials on cold work steel test specimens with different sheet thicknesses were performed. The extensions of the generated cut kerf and of the heat-affected zone as well as the recast layer were analyzed in order to reach a better understanding of the physical mechanisms which take part in the cutting process. The experimental evaluation of transmitted and reflected energy losses throughout the kerf was realized by means of PMMA (Polymethylmethacrylate) blocks placed under the sheet during the cutting process.