<title>On-line measurements of beam quality parameters on industrial CO2 lasers related to capabilities in material processing</title>

Abstract

The main parameters used for describing the beam quality of CO<SUB>2</SUB> lasers are the Beam Quality Number, energy distribution, the geometry of the beam path including the beam waist diameter, position of the beam waist and the divergence of the beam. In this paper experimental investigations of the relationship between the beam geometry parameters and the processing performance are presented. The experiments have been carried out with a portable beam analyzing system developed at the Technical University of Denmark. The beam parameters are automatically detected within a few seconds from one single measurement in an arbitrary point in the beam path of the laser, and from these parameters the focus conditions of the beam are calculated. The experiments were made on a number of industrial used laser cutting systems in the power range 1 - 2 kW and a strong correlation between the beam parameters and the cutting performance is demonstrated. The investigations have furthermore demonstrated large possibilities for optimization of the optical systems when the beam parameters are known.