Principle of Operation

Material processing is a major domain in industrial laser applications. The type of the material to be processed decides the laser type to be used. The most commonly used lasers are the Nd:YAG and the CO2. The Nd:YAG Laser emits a beam with a wavelength of 1,064 µm and a power up to 2 kW, whereas the wavelength of the CO2 laser is 10,6 µm with an output power of up to 25 kW. Since the interaction of light with matter depends on the wavelength, it is clear that particular materials can be processed more efficiently with Nd:YAG laser and with the CO2 laser. However the output power of the CO2 laser can be much higher than that of the Nd:YAG laser. Choosing the right laser for the demanded process, such as welding, cutting, drilling, etc. and the kind of material to be processed is the subject of this workshop. The Nd:YAG laser will be used to train on material processing itself and to evaluate optimum process parameters for a given material like steel, aluminium alloy, stainless steel, brass, ceramics and so on. Furthermore, the influence of assisting gases like oxygen and inert gases on the process will be studied. The Nd:YAG laser resonator is equipped with an active q-switch device which allows the increase of the output power to a 250 kW peak power per pulse. The repetition rate can be varied from 0-1 kHz. This kind of operation is useful for laser drilling. Although the power is available only for a duration of 60 ns, the material evaporates and the laser penetrates the material like a pneumatic hammer. When using oxygen as an assisting gas, which can be blown coaxial through the laser nozzle, the application range can be expanded even further . The laser as well as the workstation is controlled by a computer. By means of an external CAD program the structure or shape to be processed is generated as an HPGL file and passed to the system where a parser converts it to movement commands for the motorised X-Y stage. The working area is 100 x 100 mm and for safety reasons completely covered in a such a way that the entire laser system can be classified as a class I laser.