97Tool Wear, Tool Life, and Economics of Metal Cutting
and limit the heat dissipation to the tool shank; this, in turn, decreases the
tool life. There is therefore an optimum rake angle at which the maximum
tool life can be achieved.
Side cutting edge angle: This angle affects the direction of chip ow.
Increasing this angle increases the width of tool edge engaged in cutting,
and the uncut chip thickness decreases. This tends to decrease the tool–chip
interface temperature and the force per unit length acting on the edge, which
increases the tool life (Juneja, 1984).
Nose radius: Because of the effect of nose radius on the tool temperature
(Table 3.1), it follows that an increase of nose radius increases the tool life.
Relief angle: An excessiv ...