GASES FOR INCREASED PRODUCTIVITY OF LASER PROCESSING

To achieve a high return on investment, laser systems must be used to their fullest capacity, avoiding power losses and downtimes. High-qual ity laser gases are therefore needed to run the laser. But if the qual ity of the gas cannot be guaranteed all the way from the cylinder to t he laser cavity, the risk of impurities such as water vapour and hydro carbons or particles being entrained into the laser system is large. U nstable laser operation and damage to the resonator optics can result, needing costly repairs. The profitability of laser operations is also affected by the selection of the assist gas. High-purity oxygen, for example, results in a correspondingly high cutting speed in mild steel . In cutting stainless steel, on the other hand, any oxidation of the cut surface must be avoided in order to preserve the corrosion resista nce. In contrast, different assist gases are used for laser welding de pending on the wavelength of the laser radiation, the material or the energy per unit length of weld. Helium is often the most convenient ch oice for CO2 laser welding of mild steel and helium-argon mixtures for aluminium; argon is suitable for Nd:YAG laser welding and productivit y is increased by small additions of oxygen. Consequently, high-purity gases and suitable gas distribution equipment are the basis for a sat isfactory return on investment.