Sheet metal cutting with a 2 kW radially polarized CO2 laser

Laser processing of sheet metals are performed with a 2 kW cylindrically polarized CO2 laser. Drilling and cutting capabilities are compared between conventional circular polarization and radial/azimuthal polarization beams of the same power. A 9 mm-thick mild steel is drilled with O2 assist and azimuthal polarization shows a 15% faster drilling rate than circular polarization. A 4.5 mm-thick mild steel is cut with O2 assist and radial polarization shows a 50% faster cutting speed than circular polarization. Smaller surface roughness of the cut is obtained by the radial polarization. A 2 mm-thick stainless steel is cut with high-pressure N2 assist. Although no difference of the maximum cut speed between radial and circular polarizations are seen, it is possible to reduce the assist gas pressure from 0.6 MPa to 0.3 MPa in the case of radial polarization.