Fundamental Research On Electrochemical Machining Technology For Deep Narrow Grooves Of Titanium Alloys

The deep narrow groove structures of titanium alloy are widely used in aviation,aerospace,defense,and other industries,and plays a very important role.These deep narrow structures not only require smaller width dimensions,but also require a high length-width ratio and high depth-width ratio.Electrochemical machining?ECM?is based on the electrochemical dissolution properties of materials,which removes workpiece materials by oxidation-reduction reaction.This method has the advantages of wide adaptability of workpiece materials,high machining speed,the absence of cathode wear,and no thermal stress during machining process,and is more suitable for deep narrow groove machining of difficult-to-machine materials.However,with the increase of the length-width ratio and depth-width ratio,the electrolyte pressure in the machining gap decreases along the flow path,and the electrolytic products are difficult to be discharged in the ECM process.At the same time,the length-width ratio and depth-width ratio of cathode are also increasing,the difficulty of manufacturing cathode is multiplied and the whole rigidity if cathode is hard to guarantee,which restricts the application of ECM in deep narrow groove of titanium alloy.In this paper,the deep narrow groove of TB6 titanium alloys is taken as the research object.First of all,the electrochemical dissolution characteristics of the workpiece materials and the influence of the cathode structure on the stability of the machining process are studied by simulation.After that,the parameters of ECM were optimized by comparing the experimental research of the process.Finally,the linear deep narrow groove structure with the entrance average groove width of 2.45mm,the average groove width of 2.68mm along the depth direction,and the depth-width ratio of 11:1 and the curved deep narrow groove with the entrance average groove width of 2.47mm,the average groove width of 2.70mm along the depth direction,and the depth-width ratio of 15:1 are machined by experiment.The primary research contents of this paper including:1.Theoretical analysis and basic experimental research.Basic on the principle of electrochemical anodic dissolution,the basic experimental study on electrochemical dissolution characteristics of TB6 titanium alloys was carried out.By analyzing the decomposition voltage,^??-icurve and surface quality of TB6 titanium alloys under different electrolyte solution,the proper electrolyte composition was selected.In additional,combined with the charateristics of the deep narrow groove structure and the difficulties in machining process,the influencing factors of the stability and precision of the deep narrow groove in ECM are analyzed,and the corresponding measures are taken to improve it,which lays a theoretical foundation for later research.2.Fixture design for electrochemical machining of deep narrow groove.In order to solve the problem of the rigidity of the slice cathode with high length-width ratio and high depth-width ratio,various slice cathode structures were designed by three-dimensional software.The deformation of slice cathode was analyzed by ANSYS fluid dynamic module and Static Structural module.The maximum deformation and maximum equivalent stress of various cathode structures are compared and analyzed,and the structure of the cathode is optimized to meet the requirement of rigidity.On the basis of meeting the rigid requirements,the influence of the parameters of the stiffener on the flow field of electrolyte in the machining gap was studied by numerical analysis.By comparing and analyzing the simulation results,the cathode structure which can satisfy the rigidity requirement and guarantee the stability of electrolyte flow field is chosen.3.Experimental research on electrochemical machining of linear groove and curved groove.According to the results of theoretical analysis and simulation analysis,comparative experiments of different cathode structures,different cathode feed modes and different processing parameters were carried out.By analyzing the maximum feed rate of cathodes with different structures,the effect of the cathode structure on machining stability is verified by the previous theory.Based on the single factor comparison test of different cathode feeding modes,the influence of vibration parameters on machining stability and precision is analyzed.Finally,the test results of different processing parameters are comprehensively analyzed,the process parameters are optimized,and the linear and curved deep narrow groove structure satisfying the test requirements are processed.