Theoretical modeling and experimental validation of specific cutting force for micro end milling

Specific cutting force plays an important role on the surface quality in a micro cutting process. In this paper, a milling force model for micro end milling is established based on size effect of specific cutting force and validated by a series of micro end milling experiments. The specific cutting force is calculated by the milling force divided by the milling area. The mean value of the specific cutting force is adopted to evaluate its variation in a micro milling process. The experimental results show that the specific cutting force of micro milling increases with the decreases of feed per tooth and axial depth of cut. The specific cutting force of micro milling increases with the decrease of the helical angle in the ox direction and oy direction, and it decreases in the oz direction due to the effect of the helical angle. The cutting tool diameter has a minor effect on the specific cutting force. The specific cutting force in down-milling is larger than that in up-milling due to the impact of the cutting tool on the work piece.