For the manufacturing of micro molds, usually, the same sort of materials is used as for conventional machining. However, phenomena that occur when the depth of cut approaches the cutting edge radius have to be considered. This paper presents experimental investigations on tool life tests of micromilling processes. TiAlN-coated cemented carbide tools are applied on three different mold steels for plastic injection molding. The influences of two different types of inclusions are explored on tool wear, cutting forces, chip formation, burr formation, and surface finishing of the machined specimens.