In-process tool flank wear identification in face milling using Holm's contacts theory

Holm's contacts theory is a theory experimentally obtained for the contact electrical resistance value of metal -to-metal contacts. It has been reported that the value of this contact electrical resistance changes with the area of the contact surface if the contact pressure does not change. On the other hand, in cutting, as the flank wear of the tool progresses, the contact area between the tool and the work material increases. The authors have focused on the increase in the contact area between the tool and the work material due to the progress of tool wear and devised an in-process measurement method for the contact electrical resistance between the tool and the work material in intermittent cutting process. And it was found that there is a good relationship between the progress of tool flank wear and the change in contact electrical resistance between the tool and the work material. In this study, Holm's contact theory was used as a method to identify the flank wear width from the change in the contact electrical resistance value. Considering combinations of cutting tool materials, with or without of coating, use of cutting fluid, and work material grades, etc., the number of conditions to be verified is extremely large. As a result, although the cutting conditions were very limited, however good identification results were obtained in areas where the depth of cut was small.