Effect of cutting speed on cutting force and machining error in micro-ball end milling

Abstract

Cutting processes in micro milling of inclined workpieces with miniaturized ball end mills are discussed. The effects of cutting speed on the cutting force and machining error were investigated with changes in the cutting area on the cutting edge, which was controlled by the inclination angle of the workpiece. The resultant cutting force F_xz in x and z directions decreases when the cutting speed increases under a constant depth of cut and feed rate. Then, the tool displacement δ_t', which induces machining error, increases with the cutting force F_xz. As the tool displacement is linearly associated with the static load applied to the tool, the tool displacement can be predicted by the maximum cutting force and the machining error can be compensated by controlling the depth of cut. In cutting tests, the machining errors become less than 1 μm in milling with 0.4-mm diameter ball end mills.