Abstract: A new method for evaluating the ability of cutting tool against its early fracture is developed fron the energy viewpoint. The authors analyse the energy convertion during metal cutting and demonstrate that each kind of energy in metal cutting can be linearly estimated by the actually measured physical parameters-cutting force, cutting temperature and tool-chip contact length. A linear regression equation in terms of these parameters is then proposed and a new experimental paramet0r e, the critical specific impact power, which is dependent upon the early fracture of the tool, is in turn derived from the equation. A seriers of intermittent cutting tests are performed and show that the values of a of a carbide blade when machining different materials are nearly the same and the differences of the values of a among different carbide blades have a very good agreement with the differences among their abilities against the early fracture. As a is determined in actual cutting process, it can be expected that the critical specific impact power would superior to the traditional static mechanical parameters, such as bending, strength and impact value, in evaluating the ability of cutting tool against its early fracture.

Key words: Macro-micro cross-scale, Mechanics mechanism, Operating behavior, Thin-walled cone sleeve