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

摘要

Laser cutting is still the most common industrial application of CO_2 laser systems but currently available high-power fibre lasers seem to be an attractive alternative to the established CO_2 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 CO_2 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.