Research On Ultrasonic Vibration-assisted Micro Electrochemical Drilling And Milling

With the development of MEMS to promote the miniaturization,intelligence and integration of product components,how to improve the machining precision and machining efficiency of micro-components has become a research hotspot for scholars in the field of micro machining at home and abroad.Micro ECM has become a promising machining method in the field of micro machining,because of its advantages of high precision,no residual mechanical stress,no thermal stress,tool wear and hardness limitation.This thesis mainly studies the combination of high-speed rotation of spiral cylindrical microelectrodes and ultrasonic frequency vibration to improve the machining precision,stability,surface machining quality and machining efficiency of micro-electrolysis machining,and research on related technologies of micro electrochemical drilling and milling,the research contents completed in this thesis mainly include:(1)Based on high frequency pulse micro ECM,the influence of ultrasonic vibration on electrolyte flow and pressure field in machining gap is analyzed.The conclusion that ultrasonic vibration can improve the machining precision,stability,surface quality and efficiency of micro ECM is drawn.The mathematical model of micro-electrochemical drilling and milling is established.Finally,ultrasonic vibration assisted micro-electrochemical machining tool was built according to the requirements of use.(2)The effects of different rotation speeds on the shape and efficiency of cylindrical microelectrodes were studied.By controlling the rotation speed and machining voltage,the third-order cylindrical microelectrodes with the diameter of 15?m and the coaxiality error of less than 1?m and the pitch of 167?m with the thread height of 15?m were fabricated,and the machining times of the electrodes were significantly shortened.(3)Under the guidance of theory,the comparative experiments of micro electrochemical drilling with or without ultrasonic assisted are carried out,and the effects of ultrasonic vibration,machining voltage,pulse parameters and feed speed on machining precision of micro holes are verified.The results show that the machining precision,stability and efficiency of micro electrochemical drilling can be improved by ultrasonic vibration assisted.Within a certain range of amplitude,the higher the ultrasonic amplitude,the higher the stability and material removal efficiency of micro electrochemical drilling,the higher the machining voltage and pulse parameters,the lower the machining precision,but the higher the stability;the higher the feed speed,the higher the machining precision,but the higher the material removal efficiency.Finally,by optimizing the machining parameters,the diameter of the inlet and outlet is(D157?m and?153?m,and the array micro-holes with better consistency and lower taper were fabricated.(4)Ultrasonic vibration-assisted micro electrochemical milling experiments were carried out.Because the feed direction of drilling and milling is different,the influence of parameters on micro electrochemical milling is the same as that of drilling,and the surface roughness of micro-groove bottom surface is reduced from Ra0.83?m to Ra0.26?m.Finally,two-dimensional and three-dimensional micro-structures with better morphology and lower surface roughness are obtained by optimizing machining parameters.