Cavitation water-suction polishing of metallic materials under negative pressure effect

This study aimed to determine the erosion effects of negative-pressure cavitation on material removal and surface roughness, and to improve the efficiency of water fluid polishing. We presented a cavitation water suction polishing (CWSP) without abrasives condition to remove materials through a green manufacturing method. No pollution was generated in the circulation polishing process, and the CWSP technique was eco-friendly. The principle of CWSP under negative-pressure suction-flow condition was analyzed, and the removal mechanism of the metallic material was investigated. The material removal shape in the pressure and velocity fields of the suction jet were predicted by using the Fluent software. Variations in the content of cavitation bubbles in the water fluid under different outlet and inlet pressures were simulated. The simulation results showed that the cavitation intensity increased with decreasing outlet pressure or increasing inlet pressure. A higher cavitation content in the fluid water led to stronger erosion effect. Experiments on CWSP without abrasives were performed on the Al6061 and Cu h62 materials, and evident material removal was observed through a large amount of cavitation erosion. The surface roughness of A16061 decreased from Ra 185.8 nm to Ra 91.1 nm, and that of Cu h62 decreased from Ra 180.6 nm to Ra 75.1 nm. These findings indicated that CWSP without abrasives under negative-pressure condition could be used as an enhanced method for material removal in green manufacturing.