Study On Combined Electro-machining Technology Of Efficient And Precise For Multi-stage Internal Cone Hole

The multi-stage internal cone hole integral component is connected by inner holes of different diameters through taper angles.Because it has the advantages of compact structure,it is widely used in defense equipment,aerospace and other fields.The traditional mechanical machining has many technical bottlenecks,such as low processing efficiency,poor surface quality,difficult to control the taper precision accurately,which cannot meet the actual production needs.Electrochemical machining and polishing combined machining technology is proposed in this paper,to carry out research on basic theory and key technology of efficient and precise electro-machining of multi-stage internal cone hole,which has important theoretical significance and practical application value.In this paper,based on the analysis of relevant literature at home and abroad,aiming at the problems of low processing efficiency and poor forming accuracy in traditional machining of multi-stage internal cone hole integral components,a fluid power self-driven rotating magnetic field small gap electrochemical machining method is proposed.The impeller of the cathode tail is driven by the high speed flow of the electrolyte itself,and drives the rotation of the cathode core shaft with magnetic blocks,a rotating magnetic field is generated in the machining gap between the work-piece and the cathode.The simulation of fluid power self-driving rotation is carried out,the fluid power self-driving rotating magnetic field cathode is designed and the experiment is carried out.The work piece after electrochemical machining is composite polished to realize its high efficiency and precision machining.The simulation of cathode profile and fluid power self-drive rotation gap sudden flow field are carried out.A three-dimensional simulation model of fluid power self-drive rotation is established.In the basin where the cathode shaft is located,the rotation characteristics of the impeller at the tail of the cathode shaft driven by electrolyte are studied by CFD method.By changing the blade number and thickness of the impeller,the influence of different blade structures on the uniformity of the electrolyte flow field is analyzed when the electrolyte driven by the minimum flow rate.At the same time,by changing the inlet velocity of electrolyte,the rotation law of cathode tail inlaid impeller under different electrolyte flow velocity is studied.The cathode optimization design of multi-stage internal cone hole is carried out.In order to improve the accuracy and stability of electrochemical machining for multi-stage internal cone hole,using the small gap electrochemical machining method,and the structure of the multi-stage internal cone hole is optimized.The feed rate of the cathode in the mobile electrochemical machining of multi-stage internal cone hole is calculated.Finally,the optimized cathode is used to process the qualified multi-stage internal cone hole samples on the horizontal NC electrolytic machining machine.The maximum error of machining dimension is not more than 0.1mm and the surface roughness is Ra0.697μm.In order to improve the surface quality of multi-stage internal cone hole,the study of electromechanical composite polishing experiment is completed.The composite polishing cathode is designed according to the structure of multi-stage internal cone hole.The experiment platform for electromechanical composite polishing is established,and the experiment parameters of composite polishing process are determined.The effect of different electrolyte concentration and abrasive particles on the surface roughness of multi-stage internal cone hole is studied,a comparative experiment is carried out on the influence of mechanical polishing,electrochemical polishing and composite polishing on the surface quality of multi-stage internal cone hole.The results show that the surface quality of multi-stage internal cone hole can be better by electromechanical composite polishing.By using the combined machining method of electromechanical machining and composite polishing,the qualified sample of multi-stage internal cone hole is machined with a surface roughness of Ra0.325μm.The overall machining efficiency is 2.3 times of the traditional machining efficiency.