Abstract
This paper discusses the MQL turning of ferrous metals—chromium-molybdenum steel SCM440H and pearlite malleable cast iron FCMP—using specified MQL turning tools. The tool holder has a branched oil hole that extends to two nozzles near the flank face and the rake face of the insert. Oil mist is thus supplied directly to both the flank–chip and rake–work contact zones. The effects of oil mist supplied to flank face and rake face were investigated. With regard to the cutting force in turning of SCM440H, the oil mist supplied to the rake face is more effective at low cutting speeds below 100 m/min. In contrast, the surface roughness of the workpiece is improved by the oil mist supplied to the flank face over a wide cutting speed range of 30–300 m/min. The tool temperature of SCM440H turning when the oil mist is supplied only to flank face is approximately 70°C lower than that in dry turning, whereas it drops by as much as 100°C when the oil mist is supplied to both faces.
