Effect of nozzles on cutting performance when machining with oil-on-water cooling technique

Abstract

Previous studies identified the oil-on-water (OoW) cooling technique as an effective method to improve the cutting performance when machining compacted graphite iron. The effects of nozzle type, outlet distance, and air pressure were identified by comparing droplet diameters and cutting performances. The results showed that smaller droplets achieved a better penetration ability. In the horizontal and vertical directions, the diameter of OoW droplets increased with increasing distance from the nozzle outlet position. With increasing air pressure, the droplet diameter decreased. At an air pressure of 0.35 MPa, the diameter of OoW droplets of nozzle II decreased by 12%, 34%, and 30% compared with droplets of nozzles I, III, and IV, respectively. Of the four different nozzles, nozzle II had the smallest droplets. Under the spray-to-rake and flank faces external OoW condition, the cutting temperature of nozzle II decreased by 9%, 33%, and 27% compared with those of nozzles I, III, and IV, respectively. The surface roughness of nozzle II decreased by 20%, 27%, and 24% compared with those of nozzles I, III, and IV, respectively. The flank wear width of nozzle II decreased by 2.7%, 13.6%, and 1.4% compared with those of nozzles I, III, and IV, respectively. Moreover, nozzle II showed minimal adhesive wear, abrasive wear, and coating peeling on both rake face and flank face. Therefore, nozzle II had better cooling and lubricating abilities and achieved the best cutting performance.