Tool Wear or Tool Design

Summary

There are a group of problems which on face value appear to be associated with tool-wear mechanisms, but which, after a careful examination are either design based or metallurgical in their nature.

This paper deals with one such case and is concerned with the problems of uneven flank wear on a large, helically fluted form milling cutter. The problem caused great concern because considerable delays in production occurred because of premature failure of the cutting edge.

The fundamental problem is defined and discussed and a series of controlled tests are described in order to establish the criterion contributing most to the wear mechanism. It is shown, using a non-dimensional wear-rate that the rake angle has the predominant effect upon wear-rate for the particular tool-workpiece combination.

After careful measurements made upon the cutter it is shown that the manufacturing techniques used for the form cutter lead to incorrect rake-face geometry and consequently varying rake angle over the cutting face.

An analysis of the geometry forms part of a larger programme of research but an indication of the mechanism is given in the paper.