The manufacturing of medical implants and the micro die- and mould-machining are typical fields of application for five-axis micromilling. The machined materials diversify from NiTi shape memory alloys to hardened steels. First experimental results reveal a strong dependency of the machinability of the aforementioned engineering materials on cutter inclination angles. This paper presents a simulation-based approach mainly to optimize the tool inclination angles. The developed new algorithm is not only capable of detecting unfavourable tool inclinations for machining freeform surfaces, it also readjusts them. The verification of the established algorithm is accomplished by the machining a reference workpiece.