ABSTRACT
The mechanism of tool wear is extremely complicated and depends on the material of the tool, workpiece to be machined, cutting variables including speed and chip cross-sectional area, type of coolant, tool geometry, and the condition of the machine tool and its rigidity. It is important to note that the tool wear in metal-cutting processes is mainly due to adhesion and abrasion. At medium cutting speeds, tool wear occurs simultaneously in its flank and face. At low cutting speeds, a substantial tool wear occurs, primarily at the tool flank. The slope of the line in this period depends on the cutting conditions, tool geometry, type of coolant, and workpiece and tool materials. Crater wear is more prominent when machining ductile metals and their alloys, whereas flank wear is prevalent in brittle materials of discontinuous chips regardless of the tool material used. Because these fragments are highly work-hardened materials, their rubbing against the tool flank surface increases the tool wear rate.
