Recent progress in laser surface treatment: II. Adopted processing for high efficiency and quality

In Part I of this contribution, energy coupling and transport mechanisms were considered in detail. The second part concentrates on the effect of the spatial distribution of the energy in the laser beam, which will be discussed in connection with applications of laser surface technologies. Along these lines, a variety of beam shaping facilities is presented for laser hardening and cladding. Their purpose is to adapt the irradiated area to the workpiece geometry in order to achieve optimum energy coupling and processing quality. As an example, the use of beam combining optics permits of pre- and postheating, thereby offering interesting variations in the process. Means and techniques to enhance quality by controlling the process are also demonstrated. The principles discussed are practically independent of the laser wavelength, so that this aspect will not be treated explicitly.