Dynamics of ripple formation and melt flow in laser beam cutting

The dynamical behaviour of the laser beam fusion cutting process of metals is investigated. Integral methods such as the variational formulation are a pplied to the partial differential equations for the free boundary problem and a finite dimensional approximation of the dynamical system is obtained. The model describes the shape of the evolving cutting kerf and the melt fl ow. The analysis is aimed at revealing the characteristic features of the r esultant cut, for example, ripple formation and adherent dress. The formati on of the ripples in the upper part of the cut, where no resolidified mater ial is detectable, is discussed in detail. A comparison with numerical simu lations and experiments is made.