Study On Mechanism And Process Of Negative Pressure Cavitation Suction Polishing

Micro metal mold polishing has always been a research hotspot in the field of precision processing,and its surface quality requirements have become higher and higher.For the surface polishing of tiny metal molds,abrasive water jet technology is an economical and effective method.However,the common problem in the abrasive water jet is that the uniformity of the abrasive mixture is difficult to control and the recycling cost is high,which is easy to cause pollution,and the surface after polishing has scratches and cracks.This paper proposes the use of negative pressure cavitation suction polishing in order to superfinely polish the surface of tiny workpieces by th e micro removal of cavitation effect.In this paper,the principle and experiment of negative pressure cavitation suction polishing are discussed.The main research contents include the following aspects:(1)The basic principle of jet and the removal mechanism of negative pressure cavitation are introduced.Combining with the theory of cavitation bubble collapse,the removal effect of cavitation effect on material surface is analyzed.The micro-jet and shock wave produced by cavitation bubble collapse is the main influencing factor of material surface removal.The influence of simple low pressure on material removal is very weak.(2)The flow fields of vertical jet and inclined jet in plane and curved surface are simulated by using the fluid dynamics simulation software Fluent.Vertical jet and inclined jet are predicted by velocity field,pressure field and turbulent kinetic energy field of the jet.The variation of cavitation bubble content under different polishing distance,polishing angle,ambient negative pressure and inlet injection pressure is simulated and analyzed.(3)The experimental device for cavitation jet polishing was designed and built,and the stability of the device has been tested.The validation experiment of cavitation water-suction polishing on Al 6061 has been carried out.By measuring the surface roughness and the micro-morphology,it is verified that the cavitation effect has obvious micro removal effect on the surface of the workpiece.(4)The technological experiments of different parameters have been carried out.Through the polishing experiments of Al 6061 and H62/Cu,the effects of different inlet pressure,polishing distance,polishing time,polishing angle and abrasive on the surface quality have been researched.The results show that the cavitation water-suction polishing method can effectively remove materials on the surface of micro-workpiece,and the surface roughness after processing can reach Ra 75.1nm.