Tool wear

A more general form of the equation is where At high temperature zones crater wear occurs.

This somewhat offsets the tool wear from increased cutting speeds.

Malakooti and Deviprasad (1989) introduced the multi-criteria metal cutting problem where the criteria could be cost per part, production time per part, and quality of surface.

Also, Malakooti et al. (1990) proposed a method to rank the materials in terms of machinability.

Malakooti (2013) presents a comprehensive discussion about tool life and its multi-criteria problem.

Crater wear
Temperature gradient of tool, workpiece and chip during orthogonal cutting. As can easily be seen, heat is removed from the workpiece and the tool to the chip. Crater wear occurs around the 720 degree area of the tool.