Abstract: From the theory of up-curl chip breaking limits, the predictive formula of chip’s cross curling radius and that of critical feed-rate, all of which are about two-dimensional groove inserts, is got. Based on the theory of chip dynamics and it’s breaking foundation in the formation process of side-curl short-spiral chip, the critical depth-of-cut is formulated. Through systemic experimental study, it is proved that the results of experiments match that of the theoretical predictive formula well. The base of groove designing and chip breaking system of three-dimensional inserts is also made.

Key words: Breaking limits, Chip, Critical depth-of-cut, Critical feed-rate