Application of Tool-Work Contact Electrical Resistance Measurement to Flat End Milling

Our previous studies have shown that the change in tool-work contact electrical resistance is highly correlated with the progress of tool flank wear. This makes in-process detection of face milling tool flank wear possible. The measurement system we developed for this method starts measuring with a binary signal of the thermal electromotive force (E.M.F.) generated by the contact between the tool and workpiece. The polarity and voltage of this E.M.F. differ depending on the combination of tool material and workpiece material. We developed an operation timing circuit so that the conventional system can respond to the E.M.F. of various tools. Then, we installed it in a measurement system and conducted cutting experiments using a new end mill. As a result, it was found that the tool-work contact electrical resistance also changes with changes in the contact area during end milling.