Laser cutting of metals is one of the most common applications in industrial manufacturing. Due to this, every improvement of process efficiency and the consequential increase of cutting velocity while maintaining the quality implies a high economic potential. A key factor influencing the maximum cutting speed is the distribution of the absorbed laser power which depends on the polarization state of the incident laser beam.
This work presents experimental results obtained with a radially polarized CO2 Laser with an output power of 3700W. These results are compared with results from cutting with a standard circularly polarized beam. The investigation is focused on the different behavior of the cutting process due to the different polarization states. The emission spectra of the cutting front were measured with a spectrometer with high spatial resolution. The temperature was determined by fitting a Planck black-body radiation to the calibrated continuum emission. The temperature measurement has an accuracy of ±100K and a spatial resolution of 136 measurement points along the cut front.
The temperature profiles of the cutting front are shown to be different for the two polarizations. This difference is supposed to be the reason for the observed difference in the resulting cutting edge surface.