Multibeam fiber laser cutting

The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the $CO2$ laser. However, quality problems in fiber-laser cutting have until now limited its application to metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness and short wavelength lasers will be presented. In the approach, multibeam patterns are applied to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single mode fiber laser power. Burr free cuts in 1 mm steel and aluminum and in 1 and 2 mm AISI 304 stainless steel is demonstrated over a wide range of cutting rates. The industrial realization of this approach is foreseen to be performed by either beam patterning by diffractive optical elements or multibeam fiber laser arrangements.