Measurement of Tool Edge Temperature under Coolant Supply using Two-color Pyrometer with Optical Fiber

Development of Measurement Method and Application for CBN and Poly Crystalline Diamond Tools

Abstract

In this study, the method of tool edge temperature using two-color pyrometer in wet cutting is proposed. Using this method, the high pressure air supplied from small hole for an optical fiber prevents coolant from adhering to the optical fiber edge and makes temperature measuring possible. Air pressure never affects tool edge temperature measured using two-color pyrometer. In this way, the tool edge temperature of CBN and Poly Crystalline Diamond (PCD) tool is measured in turning of Ti-6Al-4V. As a result, the tool edge temperature is increases rapidly with the increase of cutting speed. In dry turning of Ti-6Al-4V, PCD tool edge temperature is almost 100oC lower compared with CBN tool edge temperature. Supplying coolant, CBN tool edge temperature is reduced about 70 oC and PCD tool edge temperature is reduced about 340 oC compared with tool edge in dry turning resistivity.