Optimisation of tool angles and the relation between tool path and cutting force in high-speed milling with micro-end-mill

On the basis of high-speed milling experiments of hardened steel, two technical problems associated with micro-end-mill tools have been investigated in this paper. The optimisation of tool angles was discussed firstly. Cutting force, cutting vibration and tool wear areas of different tool rake angle γο, frank angle αο and helix angle β are recorded and analysed, and recommended tool angles are proposed. The milling process will be steady with negative rake angle, except that the tool wear is little severe. Longer life will be obtained with small positive rake angle about 0–5° in the high-speed milling of hardened steel. It is appropriate to adopt the clearance angle as high as 15°. The helix angle can be designed as 0° for longer tool life or 30° for integrated performance. The changes of cutting force under different tool paths have also been analysed. The cutting forces of side milling and slot milling with the same material removal rate are compared. Milling experiments of different line corners have also been completed and the changes of cutting force are analysed. It can be concluded that cutting force is not only decided by material removal rate in high-speed milling with micro-end-mill. The direction of feedrate and the feed system of the worktable machine tool need to be paid attention to.