Experimental research on the influence of the jet parameters of minimum quantity lubrication on the lubricating property of Ni-based alloy grinding

Based on research on nanofluid minimum quantity lubrication (MQL) in grinding, a plane grinding experiment was performed on Ni-based alloy using a K-P36 precision numerical control surface grinder. Uniform grinding parameters were used in the experiment, but three groups of MQL jet parameters were changed. The grinding force was measured using a YDM-III99 three-dimensional dynamometer to calculate the specific grinding energy and coefficient of friction. The surface roughness of the workpiece was measured using a TIME3220 roughness tester. An experimental research was also conducted on the droplet size and velocity of the jet using a high-speed camera system. Results showed that the most ideal lubricating effect was achieved under 0.5 MPa compressed gas, 0.4 gas–liquid ratio, and 0.005 kg/s liquid flow rate. Under the best jet flow condition, the specific tangential grinding force, specific grinding energy, and coefficient of friction were 1.45 N/mm, 74.57 J/mm3, and 0.414, respectively. The surface roughness of the workpiece was at its most ideal at this point, where Ra, Rz, and RSm were 0.249 μm, 1.972 μm, and 0.028 mm, respectively. Based on high-speed continuous shooting at the jet, the mean droplet size was about 171.82 μm under the optimum jet parameters, and the droplets exhibited variable accelerations at a high accelerated velocity (>500 m/s2).