Simulation of cutting tool wear by a modified pin-on-disc test

Abstract Metal cutting is characterized by extreme contact conditions at the tool-workpiece interface which cannot be simulated in a conventional wear test. Consequently, the performance of the tool material is normally evaluated by full-scale, comparative cutting tests. In this type of test, the observed tool lives are determined by both gradual wear and edge chipping. This creates a problem in the development of new tool materials and coatings since the tool material wear resistance cannot be determined separately. In order to overcome this experimental difficulty, a modified pin-on-disc test has been developed. In this test, the contact conditions in machining are reproduced by letting the pin slide against a newly formed, unoxidized countermaterial surface. In the present work, the performance of this new test has been evaluated for high speed steel tool wear with a quenched and tempered steel, AISI 4340, as countermaterial. The influence of normal force, sliding speed and sliding distance on wear and friction has been investigated. The observed wear rates and wear mechanisms are compared to results from conventional laboratory wear testing (using the same test set-up) and machining. The experimental results demonstrate that the new wear test produces wear characteristics that closely correspond to tool wear. Thus, the modified pin-on-disc test exhibits great potential as a first screening wear test of new tool materials and coatings.