Method for Cutting Stainless Steel with a Fiber Laser

Abstract

The invention relates to a laser cutting method for cutting a stainless steel workpiece using laser beam generation means comprising a silica fibre with an ytterbium-doped core to generate the laser beam. Preferably, the laser beam generated by the ytterbium-based fibre has a wavelength between 1.07 and 1.09 μm, a quality factor of the laser beam is between 0.33 and 8 mm.mrad, and the laser beam has a power of between 0.1 and 25 kW. The assistance gas for the laser beam is chosen from nitrogen, helium, argon and mixtures thereof, and, optionally, it further contains one or more additional compounds chosen from O 2 , CO 2 , H 2 and CH 4 .

1 . A laser cutting method for cutting a stainless steel workpiece, in which laser beam generation means comprising at least one ytterbium-containing fiber for generating a laser beam are used to melt the workpiece and thereby perform the actual cutting, wherein the quality factor of the laser beam is between 0.33 and 8 mm.mrad. 
     
     
         2 . The method of  claim 1 , wherein the fiber is formed from an ytterbium-doped core clad with silica. 
     
     
         3 . The method of  claim 1 , wherein the laser beam generated by the ytterbium-based fiber has a wavelength between 1 and 5 μm, preferably between 1.04 and 3 μm. 
     
     
         4 . The method of  claim 1 , wherein the laser beam generated by the ytterbium-based fiber has a wavelength between 1.07 and 1.09 μm, preferably of 1.07 μm. 
     
     
         5 . The method of  claim 1 , wherein the laser beam has a power of between 0.1 and 25 kW, preferably between 0.5 and 15 kW. 
     
     
         6 . The method of  claim 1 , wherein the laser beam is a continuous or pulsed laser beam, preferably a continuous laser beam. 
     
     
         7 . The method of  claim 1 , wherein the workpiece to be cut has a thickness between 0.25 and 30 mm, preferably between 0.40 and 20 mm. 
     
     
         8 . The method of  claim 1 , wherein the cutting speed is between 0.1 and 25 m/min, preferably from 2 to 20 m/min. 
     
     
         9 . The method of  claim 1 , wherein the assistance gas for the laser beam is chosen from nitrogen, helium, argon and mixtures thereof, and it further contains one or more additional compounds chosen from O 2 , CO 2 , H 2  and CH 4 . 
     
     
         10 . The method of  claim 1 , wherein the quality factor of the laser beam is between 1 and 8 mm.mrad, preferably greater than 2 mm.mrad, even more preferably greater than 3 mm.mrad and/or preferably less than 7 mm.mrad and even more preferably less than 5 mm.mrad.