Why is machining friction different from conventional fricti

Why is machining friction different from conventional friction?

Solution

During machining, the temperature of the material goes high and it leads to changes in physical properties of the metals. It is suggested that sliding and sub-surface plastic deformation may occur simultaneously. When machining under dry, unlubricated conditions regions of sticking friction where the frictional stress is constant and sliding friction where the coefficient of friction is constant can exist simultaneously on the tool rake face. This is why machining friction is different from conventional friction.