| New technologies has burgeoned greatly in recent years,such as war industry,space navigation,pharmacology and bionics,the development of traditional mechanical manufacturing industry is facing higher and newer challenges.All kinds of difficult-to-machine materials and special-shaped surface parts are widely used in machinery,automobile,biology,aviation,military and other industries.As such parts are difficult to process and require high machining requirements,it is difficult to achieve high precision and efficient machining by traditional machining methods.In recent 20 years,new advanced special machining technology and its compound processing method have been emerging continuously,because the processing can not be affected by material hardness,the processing force is small（or none）,the tool loss is low（or none）,and it has been widely used in the processing of difficult-to-machine materials and parts with special-shaped surfaces.Rotating ultrasonic,ultrasonic effect and pulse electrolysis are combined organically to overcome the limitations of single ultrasonic and ultrasonic composite electrolysis technology and achieve complementary advantages of multiple technologies.On this basis,a new method of 2-D rotating ultrasonic composite electrochemical machining is put forward further,aiming at precise and efficient machining of difficult-to-machine materials and parts with special-shaped surfaces.The fundamental substance are as as listed below:1.Analyse the rotating ultrasonic composite electrochemical machining process,carry out mechanism analysis on rotating ultrasonic machining and ultrasonic composite electrochemical machining,establish material removal efficiency models respectively,and explore the factors affecting the processing efficiency;Based on the material removal principle and efficiency model of rotating ultrasonic machining and ultrasonic composite electrochemical machining,the material removal efficiency model of rotating ultrasonic composite electrochemical machining is deduced.The factors influencing the processing efficiency are:spindle rotating speed n,ultrasonic frequency f,ultrasonic amplitude A,pulse voltage U,electrolyte conductivity σ.And the size and hardness of fine abrasive particles;The coupling relationship between ultrasonic and electrolytic parameters is analyzed and coordinated to optimize matching of processing parameters.The forming mechanism of two-dimensional（axial and radial）rotating ultrasonic composite electrochemical machining was analyzed.2.Put forward the general scheme of rotating ultrasonic composite electrochemical machining system,design and construct rotating ultrasonic composite electrochemical machining system,carry out analysis and design of each component of rotating ultrasonic vibration system,i.e.the design of rotating ultrasonic electro-spindle,piezoelectric ultrasonic transducer,ultrasonic horn and tool electrode;A radial ultrasonic vibration device is designed to realize a 2-D rotating ultrasonic composite electrochemical machining system with axial and radial combination.The multi-axle linkage feed and control system is designed.The rotating ultrasonic electro-spindle can be used as servo feed in Z-axis and the horizontal worktable can be used as straight feed in X and Y direction.Design flexible ultrasonic machining fixture;Finally,ultrasonic vibration parameters and workpiece monitoring scheme are given,including measurement of ultrasonic vibration parameters,electrical parameters during machining,conductivity of electrolyte and surface morphology of the processed workpiece.3.Modal analysis and harmonic response analysis of rotating ultrasonic vibration system are carried out by WORKBENCH.The mode analysis and harmonic response analysis of piezoelectric ultrasonic transducer and stepped ultrasonic machining horn are carried out by ANSYS using command flow programming.Due to the special size of tool electrodes,a certain size tool electrodes are introduced to model the overall structure of the new ultrasonic vibration system.The necessary optimization analysis is carried out by ANSYS to adjust the parameters of the vibration system and obtain the appropriate amplitude,which verifies that the designed ultrasonic vibration system can meet the actual processing requirements and the advantage of ANSYS in dimension design of the ultrasonic vibration system.4.Improve the two-dimensional rotating ultrasonic composite electrochemical machining test system,analyze the combination scheme of machining feed and ultrasonic vibration,and design the test scheme.The different machining methods of piezoelectric ceramics（PZT）and high-speed steel（W18Cr4V）were tested and explored,and the technical advantages of rotating ultrasonic and combined electrochemical machining were verified.Rotary ultrasonic composite electrolytic machining experiments were carried out on copper（Cu）and cemented carbide（YT15）.The electrolytic effect effectively improves the processing efficiency.Rotary ultrasonic composite electrolytic expansion cutting and two-dimensional rotational ultrasonic composite electrolytic expansion cutting experiments were carried out on bearing steel（Cr15）.The groove edges machined by the latter are free of burrs and the machining effect is better,which verifies the advantages of two-dimensional rotational ultrasonic.The experimental research on different processing methods,different electrolyte voltages and different electrolytes for particle reinforced ceramics（SiCp/Al）shows that the grooves produced by two-dimensional rotating ultrasonic composite electrolysis have higher precision,smoother plane and edge,and higher machining efficiency,which verifies the advantages of two-dimensional rotating ultrasonic composite electrolysis.The processing efficiency is proportional to the pulse electrolyte voltage,but with the increase of electrolyte voltage,Stray corrosion is more serious,the processing quality decreases,the processing quality is better when NaNO3 solution is used as electrolyte,and the processing time and surface roughness can not be optimized under the same conditions.NaNO3 solution can be selected as electrolyte. |
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