Abstract

Tool-work electrical contact resistance varies depending on the contact area between the tool and the workpiece. Specifically, as tool flank wear progresses, the contact electrical resistance reduces. This phenomenon is consistent with Holm's contact theory, even at high temperatures during cutting. We successfully measured tool-work electric contact resistance during intermittent cutting, where the cutting time per edge is short. In addition, we derived an equation to calculate flank wear width using the contact electrical resistance value. This enabled us to successfully determine flank wear width from the contact electrical resistance, albeit limited to cutting conditions with shallow depths of cut, such as finishing cuts. However, the current measurement method requires approximately 7 ms from the start of cutting to complete the measurement of contact electrical resistance. This time frame does not apply to tools with diameters less than 12 mm under standard cutting conditions when cutting carbon steel with cemented carbide tools. Within this 7-ms timeframe, overshoot of the waveform during the flow of constant current for measuring contact electrical resistance, as well as its decay time, have a significant effect on the measurement. In this study, we attempted to identify and suppress the causes of the overshoot. Although we identified the cause of overshoot, we were unable to identify the factors causing long decay times. Therefore, by altering the sequence of contact electrical resistance measurement, we successfully reduced the measurement time to 3 ms and made it compatible with measurements using smaller diameter tools.