Engineering Reference

Tool life

The cutting time a tool lasts before it must be replaced or reground.

Definition

Tool life is normally defined by a wear criterion — flank wear land width, or surface finish degradation — rather than by catastrophic failure. The Taylor relationship V·Tn = C describes how life falls as speed rises, with n typically 0.1 to 0.4.

Because n is small, a large change in speed produces a modest change in life, while the reverse is dramatic: doubling the speed may cut life to a fifth, but doubling life may only need a 15% speed reduction.

Common misuse

Judging tool life by when the tool breaks. By then the finish and dimensions have been out of specification for some time.

Related