Sources and scope for this page: ISO 513:2012, covering the definition of tool life. No independent source check is recorded for this page: the content rests on the sources listed and on the working shown on the page. How sources, methods and updates are recorded.
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.