| 摘要 |
<p>When materials are worked with a laser beam (11, 12), a plasma (14) is formed at high beam output. On account of its absorption of the laser light, this plasma (14) hinders the transfer of energy to the work piece (10). In order to render harmless the electrons mainly responsible for the absorption, helium, which promotes the recombination of electrons and ions, is blown onto the working point (13). Instead of the expensive helium, this invention uses the readily available gases CF4 and/or SF6. Together with a filling gas/inert gas to which they are admixed at less than 25%, they are blown (16) via a nozzle (15) onto the working point (13), where, under the effect of the high temperature, they form highly electronegative fluoro-radicals which remove electrons from the plasma (14). This process can be controlled via the mixture composition. The method described is especially suitable for working metals, in particular aluminium alloys. <IMAGE></p> |
