Summary Since appr. 10 years the researches on high speed cutting (hsc) are one of the scientific key points of the Institute of Cutting Technology and Machine Tools (ITW) of the Technical University of Darmstadt. One of the essential results is the fact that just known cutting mechanisms in normal speeds are also valid for hsc. But the applicable cutting mechanism depends on the mechanical characteristics of the material to be cut. Therefore there is a difference in the cutting technology of ductile and brittle materials and fiber-reinforced plastics. The knowledge of the specific cutting mechanism is also essential for the application of hsc on ultra-precision-manufacturing, in order to combine the advantages of hsc, eg. large cutting volume, reduced cutting forces and low influence of temperature, with a high surface quality.