The identification of the cutting force coefficients for ball-end finish milling

The identification of the cutting force coefficients for ball-end is mostly studied by slotting or half slotting experiments with a large cutting depth. However, in the high-speed finish milling of hard-to-cut materials, such as titanium alloy and high temperature alloy, a small cutting depth is generally adopted in order to ensure machining quality, and its axial depth is less than 0.5 mm. During the cutting process, the single tooth cutting state is always maintained and the cutter-tip point is not involved in cutting. Therefore, the cutting force coefficients identified by slotting or half slotting experiments may not be accurate in the finish milling. Accordingly, this paper proposes a method to identify the force coefficients of ball-end based on the single tooth average cutting force. In order to avoid the cutter-tip point being involved in cutting, oblique cutting experiments are used in this paper, and the cutter engagement area is obtained when the cutter is inclined. Based on the instantaneous cutting force model of ball-end, an identification model of single tooth average force coefficients is established. Compared with the average force coefficients model of the traditional whole cycle, the root mean square error of the established model in this paper is relatively small. Especially for the high-speed cutting, the error is less than 15% of the traditional method.