Engraving

Laser supported, high-volume ablation offers excellent opportunities for making high-precision printing, embossing, erosion, or injection tools. The great advantage over the conventional spark erosion technique consists in the fact that the laser is tool-free, and therefore extremely flexible as to geometry and material. In addition, of course, it is free of wear.

The ideal solution for this application is a laser system with a mean power of 90 W to 150 W that allows pulse rates of up to 50 kHz and is fitted with a standard deflector head an a motor-driven vertical feed axis. Pulse durations of 50 to 300 nanoseconds, pulse energies in the range of 5 - 15 mJ and minimum spot diameters of around 30 to 100 µm, result in power densities of several 100 MW per square centimetre at the place being processed.

Two ablation mechanisms must be differentiated, depending on the applied power density. Low intensities lead to sublimation of the material, with ablation rates of up to 0.5 cubic mm per minute in steel. At higher power densities, the ablation process changes, and sublimation-induced fusion displacement takes place. Ablation rates in metal of more than 10 cubic mm per minute can then be achieved. In the case of sublimating materials such as silicon nitrite or graphite, the ablation values can be many times more than this.

Lasers: SMP100. Rofin 100D