SECTION 4.1

Failure of the broach cutting tool has occurred when it is no longer capable of producing parts within the required specifications. The point of failure, together with the amount of wear that determines this failure, is a function of the broaching objective. Surface quality, dimensional stability, cutting forces, and production rates may alone, or in combination, be used as criteria for tool failure.

It may, for instance, take very little wear to affect surface quality, although the tool itself could continue to remove metal with little, if any, loss of efficiency. In contrast, only a few thousandths of an inch of wear on a wide tooth form might cause such a large increase in the pulling force required that it would result in a loss of dimensional stability, or worse yet, a broken broach.