A comparative study of flood cooling and minimum quantity lubrication for an eco-efficient turning

An investigation of effectiveness of Minimum Quantity Lubrication (MQL) over flood-cooling lubrication in turning operations of 25 mm diameter mild steel bar using tungsten carbide tool with chemical vapor deposition (CVD) coating. Experimental investigation targeted mainly on study of surface roughness obtained and chip formation using both lubrication procedures. Experiments were carried out using an orthogonal array (OA), and the analysis of variance (ANOVA) was applied. Turning operations were carried out using cutting speeds 460, 750, and 1250 rpm and feed rates of 0.2, 0.4, and 0.8 mm/rev. The depth of cut was maintained constant at 0.125 mm throughout the series of experiments. It was observed that cutting speed and feed rate have significant effect on surface roughness. In terms of chips produced from the turning operation, there were more discontinuous chips being obtained in flood-cooling conditions than in MQL conditions. In comparison, more segmented chips were produced in MQL conditions. The optimum process parameter setting of the experimental design was obtained with high cutting speed and low feed rate in both MQL and flood-cooling lubrication.