Effect of Minimum Quantity Lubrication on Turning Characteristics: Measurement of Tool Flank Temperature in Turning Using Fiber-Coupled Two-Color Pyrometer

摘要

In this paper, the MQL turning of two types of ferrous metals: chromium-molybdenum steel SCM440H and pearlite malleable cast iron FCMP: is dealt with. The appropriate generating system of oil mist is constructed and the specified turning tool with oil hole is used. In order to verify the cooling effect of MQL, the tool temperature at the flank face is measured using a newly assembled fiber-coupled two-color pyrometer. In this new technique, a sensing fiber is inserted into a small hole that extends to the outer surface of the tubelike workpiece and it rotates with the workpiece. The thermal radiation accepted by a sensing fiber is noncontactly transmitted to the other fixed fiber and led to the two-color detectors. As for cutting force in turning of SCM440H, MQL is more effective in low cutting speed below 100 m/min. The tool temperature in MQL turning is approximately 100°C lower than that in dry turning over the wide range of 30∼300 m/min. In the case of FCMP, the tool temperature in dry turning at a cutting speed of 600 m/min reaches as much as about 1040°C, but it drops 920°C in MQL turning.