Micromachining is not only a simple miniaturization of processes using macroscopic tools. As a matter of fact, a lot of specific concerns have to be met for successful fabrication of microstructures. This chapter will be focussed on micromachining using geometrically determined cutting edges, namely on techniques like drilling, milling and slotting. These methods are very flexible. Compared to EDM, ECM or lithographic processes like LIGA, they can be applied to a wide range of materials, like polymers, metals and alloys as well as to some kinds of ceramics, possess a high material removal rate and allow a great degree of freedom concerning design. There are nearly no geometrical limitations and also 3Dstructures can be manufactured easily.