Melt dynamics in surface processing with laser radiation
The basic physical processes of melting with laser radiation are reported especially including the free self-adjusting surface. A three dimensional stationary model for the thermocapillary flow is outlined giving indication for five independent dimensionless parameters. The numerical results show that above a critical scanning velocity the intermixing in the molten pool is completely suppressed. A two-dimensional nonstationary model in a plane parallel to the scanning velocity is reported in order to investigate the surface deformation during surface melting. The calculated surface deformation shows excellent agreement with experimental results performed with a line source power density distribution.