Abstract: Large module gear milling has the features of multi-edge intermittent cutting and variable chip thickness, thus belonging to typical non-free heavy cutting. The mechanism of intermittent cutting in gear milling is studied mainly from the aspects of cutting force, chip shape and surface quality. The instantaneous synthetic torque of a single blade is obtained by using the exponential empirical model and the stress integral of micro-segment cutting edge, and then the distribution of blades on the cutterhead is considered, the periodic load of cutterhead is obtained, and the calculation model of intermittent cutting torque is proposed. Test method of indirect measurement is used, the spindle input current of three-phase asynchronous motor is collected, and the cutting force is obtained by reconstruction. Moreover, the cutting deformation ratio is measured through tests, and the cutting force is obtained by use of theoretical formula. The test data and the theoretical calculation result are compared with the calculation model, which verifies the correctness of the model of cutting torque in gear milling. Geometric analysis of the residual height in the cutting process is carried out, and the calculation method thereof is obtained. The analysis on the mechanism of intermittent cutting in gear milling is preliminarily completed, which provides guidance for the gear milling accuracy.

Key words: Cutting deformation ratio, Gear milling, Indexable tool, Micro-segment cutting edge, Non-free cutting