Absorption distribution on idealized cutting front geometries and its significance for laser beam cutting

The absorption behaviour of metallic materials during laser beam cutting is examined under the presumption of a three dimensional cutting front model by applying the Fresnel formalism. The resulting theoretical influence of the laser beam parameters (power, mode, polarization, focal position and beam divergence) on the integral and homogeneity of the absorption distribution within the cutting front co-ordination system is described and compared with experimental results concerning the practicable cutting speed and the obtainable quality of the cut. Calculations of the power balance, considering also an estimation of heat losses, and appropriate cutting experiments are in accordance with the predicted average absorptivity of the idealized cutting front.