On laser fusion cutting - a closed formulation of the process

The process of laser fusion cutting depends on physical quantities which are not adjustable directly, but established by the process itself. Examples are the slope of the cutting front, the melt-film thickness, the surface temperature and the cutting kerf width. Especially, up to now, the cutting kerf was approximated to have the same extent as the laser beam itself. Our present model allows for the distribution of the laser intensity, the global momentum balance determining the melt-flow, and the heat-conduction equation in connection with the boundary condition for the absorbed energy density flow. The resulting three-dimensional cutting front geometry is calculated and the physical mechanism determining the cutting kerf width is discussed. In addition to the physical principles of the model, already outlinde at the SPIE-Symposium 1989 in Paris, we are now able to present a discussion of new results concerned with the parameter dependencies of the resulting cutting kerf width.