L'air Liquide, Societe Anonyme a Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude

Christophe Bertez

Olivier Matile

Jean Hamy

Method and plant for cutting or welding by a laser beam with dual-flow and double-focus cutting head. The plant includes a laser generator to generate at least one main laser beam ( ), a first optical element ( ) enabling the main laser beam ( ) to be divided into at least two subsidiary laser beams ( ), a first outlet nozzle ( ) through which one ( ) of the subsidiary laser beams passes, and a second outlet nozzle ( ) through which the other ( ) of the subsidiary laser beams passes, the first and second outlet nozzles ( ) being approximately coaxial one with the other. In this way, it is possible to focus the central beam ( ) onto a focusing point (PF) by a first focusing element ( ), such as a lens, and the other beam ( ) onto an annular focusing zone (ZAF).

Method and plant for laser cutting with dual-flow and double-focus cutting head

Method and apparatus for cutting a workpiece made of structural steel or mild steel, i.e. alloy or non-alloy steels, by the use of a transparent or reflecting optical unit for focusing a laser beam, and of an assist gas for the laser beam. The optical unit is of the multifocus type and is chosen from lenses, mirrors and combinations thereof. The assist gas is nitrogen or a nitrogen/oxygen mixture. The method of the invention makes it possible to obtain a low or almost zero oxidation of the cut face and to do so while increasing the cutting performance by about 40% compared with a laser cutting method using nitrogen or a nitrogen/oxygen mixture.

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Vaureal, France

Christophe Bertez