Research On Micro Electrochemical Drilling And Milling With High Efficiency

With the development of high and new technology,the trend of miniaturization,integration and intellectualization of products is obvious,especially in the field of micro electromechanical system(MEMS).The rapid development of MEMS and other fields has led to the increasing demand for micro components.The processing technology of micro components has become a hot topic for scholars from all over the world.Micro electrochemical machining(ECM)technology is considered to be an extremely promising micro processing method due to the advantages,which include that the machining accuracy can achieve to nanometer level,and the products have good surface quality;the material of workpieces couldn't be limited by the mechanical properties of itself;and the cathode can be reused without loss.In this paper,micro spiral electrodes with high rotating speed are used in the process of micro ECM,and the theoretical analysis and a series of experiments of drilling and milling are carried out.Below is the main content of this paper.1.At first,the process of ECM was deeply analyzed.And according to the requirements of micro ECM,the experimental set-up of micro ECM was constructed.Then the controlling model of electrochemical drilling and milling were established,based on the processing characteristics of micro ECM with nanosecond pulse power supply.The impact of spiral electrode with high rotating speed on the processing electrolyte had been simulated analyzed,then it was concluded that the machining efficiency and the machining accuracy would be both improved and the taper of holes would be decreased by applying spiral electrode with high speed rotation and nanosecond pulse power supply in ECM.Then the experiments of micro ECM were carried out in different rotating speeds to investigate the relation of the diameter of holes,the taper of holes and the maximum feeding rate to the rotating speeds,and the results proved the above theoretical analysis.2.Based on theory and effects of rotation on electrolyte field and electronic field,a method for fabricating uniform columnar electrodes with high rotation precision was proposed,and the mathematical model was established to control the shape and diameter of electrode according to experimental results;then the electrodes with diameter of about 100?m and the error of coaxiality less than 1?m were successfully fabricated.What's more,taking advantage of columnar electrodes,a method for preliminarily fabricating micro spiral electrodes was proposed by analyzing the effect of rotation on the diffusion layer,and a micro spiral electrode was fabricated successfully.3.A series of experiments on micro electrochemical drilling were carried out on the built experimental set-up,and the effects of main processing parameters,such as voltages,pulse width,pulse period and feeding rate,on the machining accuracy and stability were explored.The experimental results showed that the machining accuracy decreased with the increase of voltages and pulse width,and the stray corrosion would appear near the entrance by larger parameters,the phenomenon of short circuit would appear to reduce the machining stability in smaller parameters;the machining accuracy increased with the increase of pulse period,and the stray corrosion would appear near the entrance by small pulse period,the phenomenon of short circuit would appear by large pulse period;the machining accuracy was basically unchanged after the first increase with the increase of feeding rate,and the phenomenon of short circuit would appear to reduce the machining stability in larger feeding rate.Finally,under the optimized parameters,the array holes with good consistency and near no taper were successfully machined.4.Series of experiments on micro electrochemical milling were conducted on the experimental set-up,and the effects of main processing parameters,such as voltages,pulse width,pulse period and feeding rate,on the machining accuracy and stability were explored,the effects of parameters on the width of grooves were similar to micro electrochemical drilling.Finally,under the optimized parameters,a series of straight lines,curves and complex closed curves of grooves were successfully processed.