Fibre laser cutting: beam absorption characteristics and gas-free remote cutting

Laser cutting is still the most common industrial application of CO2 laser systems but currently available high-power fibre lasers seem to be an attractive alternative to the established CO2 laser sources for several cutting tasks. Practical experience has shown that fibre lasers enable significantly increased travel rates in the case of inert-gas fusion cutting. This advantage in achieving higher cutting speeds in comparison to CO2 laser cutting is however a clear function of the sheet thickness to be cut. In the first part of this article, possible reasons for this experimental fact are derived from a thermodynamic analysis of the process with consideration of the specific beam absorption characteristics under cutting conditions. After that, in the second part, a quite new laser cutting variant, namely the gas-free remote cutting process that considerably benefits from the high beam quality of fibre laser systems, is presented.