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High power CO2-laser systems with radiation output from 0.5 to 10 kW are ready now to be incorporated in a production line. They offer new possibilities of material processing like deep-penetration welding, transformation hardening of thin surface layers, hard facing, surface glazing, etc. At the present time, besides applications in microtechniques like spot welding, drilling and laser trimming, primarily laser cutting is used in industry. In order to achieve a universal cutting tool of high productivity, research should not only concentrate on the processing machine consisting of gas assistant components, CNC systems, beam guidance, and the laser itself, but should also take the material properties and the physical mechanism of the cutting process into consideration. On the other hand, it is important to find new ways of engineering design and manufacturing processes adapted to the specific requirements and advantages of laser cutting. As a thermal cutting method used mainly for thin sheets up to 6 mm thickness, laser gas cutting competes with the mechanical cutting methods. It is characterized by a high cutting speed, a small kerf width, a narrow heat affected zone, and a high quality cutting edge. Thus, no distortion of the workpiece occurs, and, in most cases, no finishing operations are required. In connection with a CNC table, complex two or three dimensional cuts of high accuracy can be done. Moreover, laser gas cutting can be automated easily. At the Institute of Welding and Materials Technology, we are interested in the behaviour of the material during the cutting process, in a determination of the cutting quality attainable by present laser systems, and in the mechanical properties of laser-cut elements. We are also concerned with the comparison of the various cutting methods and the classification of their fields of application. With regard to these problems, besides others, a physical understanding of the interaction between high density laser radiation and matter is required. For our purpose, however, a cutting model should be as simple as possible, able - to give an estimation of the cutting speed, - to show basically how the quality of the cutting surface depends on the process para-meters, - and to predict the metallurgical impact on the workpiece. In this paper, some primary steps are briefly given. A more detailed description of our in-vestigations will be published later.
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