Physical aspects of surface processing with laser radiation

Energy coupling, heat conduction, melting; evaporation and plasma generation including melt-, vapor- and plasma dynamics as basic physical processes for surface processing with laser radiation are reviewed. For low power densities energy transfer by heat conduction and mass transfer by diffusion are dominant with pronouncing convection and evaporation at increasing power densities. All the processes with different time constants govern the properties of the processed surface layers. High surface finish and improvement in wear-resistance, fatigue life or corrosion-resistance require adaptive control for optimum surface processing. Different approaches of mathematical analysis of the multiparameter problem surface processing with laser radiation provide a testing comparison with the physical picture and an easy estimation of process parameters in applications. Typical examples are reported to highlight the state of the art and to demonstrate the future trends in surface processing with l aser radiation.