Research Of Electrochemical Machining With Spherical Cathode And Equipment Development

In recent years, with the rapid development of society, more and more resources and environment problems occur. Remanufacturing has the characteristic of resource saving and environment friendly, so governments pay more and more attention to remanufacturing. High value-added compressor impeller for remanufacturing has important economic and environmental benefits. After the repair of compressor impeller, precision machining method will be needed to make the impeller back to size accuracy and surface quality. Electrochemical machining won’t produce residual stress, hardening layer, burns and other injuries, in addition, electrochemical machining has high machining efficiency. Electrochemical machining technology applied to the remanufacturing of compressor impeller will have important significance.Firstly, this paper studies the passivation mechanism of electrochemical machining. The voltage of active dissolution area, transition passivation area and passivation area has been acquired. The high polishing quality has been required with the good passivation parameters. Though the study of passivation mechanism, it can be known that the passivation layer occurs on the anode surface when electrochemical machining. The passivation layer can slow down the rate of electrochemical corrosion. The high polishing quality has been required with the good passivation parameters. Through the corrosion rate experiment, it can be known corrosion rate and voltage have approximately linear relationship.Then, the use of spherical cathode instead of traditional "copy" the cathode can reduce complex cathode design and improve machining accuracy. Spherical cathode numerical control electrochemical machining machine tool has been designed. The electrolyte circulating system can realize the recycle of electrolyte, filter out the electrolytic flocculation impurity and reduce the electrolyte temperature. By controlling the movement of spherical cathode on the surface of the work-piece, distortion face has been machined.Then, The removal rate of the spherical cathode electrochemical machining is studied. The mathematical model of material removal rate has been established. The empirical formula between the removal rate and the current strength has been fitted, which can be used to choose the current of material removal rate. Various factors of electrochemical machining affect the current strength, which influence the material removal rate. So the fitting formula between Voltage, electrode gap, concentration of electrolyte, pressure of electrolyte and current intensity has been established. The fitting formula can be used to choose the remove rate of the electrochemical machining. What’s more, by electrochemical machining experiment, the fitting formula between Removal rate and current strength has been proved reasonable.Finally, The influence of spherical cathode electrochemical machining on the surface quality has been studied with Orthogonal experiment and single-factor experiment. Experiment also found that the micro-hardness decreases after electrochemical machining and natural corrosion resistant ability get promoted. The weight of each factor how to influence the surface roughness has been found by orthogonal test. The influence law of various factors on the surface roughness has also been found by single test. The surface micro-hardness after electrochemical machining decreases. The Corrosion resistance after electrochemical machining has been improved. The research results could be used to provide projects selection and theoretical and technical support for the electrochemical machining of compressor impeller.