基于双电层电容的微细电解加工间隙的在线检测

Online Detection Method for Inter-Electrode Gap in Micro ECM Based on Capacitance of Electric Double Layers

根据微细电解加工中工具电极下端面面积远小于工件表面的非对称特征，在水基中性盐钝性电解液侧流冲入和金属电极处于钝化状态的条件下，提出了一种基于双电层电容的微细电解加工间隙的在线检测方法．在微细工具电极和／或工件上不外加传感器的前提下，利用工具电彬溶液界面上双电层电容值随加工间隙增大而单调递增的变化关系，精确、快速地实现加工间隙的在线检测．在冲液速度为1．058m／s的条件下，当加工间隙在O．100μm时，可在数毫秒内在线检测出微细电解加工间隙的大小，数值仿真与实验测量值之间的最大相对误差小于10％．为实现高精度、高质量、稳定的微细电解加工提供必要条件．

In accordance with the asymmetric feature that the bottom area of tool electrode is far smaller than the surface of workpiece in micro electrochemical machining （ micro ECM） , and under the condi tions that in waterbased neutral salt the blunt electrolyte sidestream flushes in and that the metal elec trode is in a passive state, the online detection method for the size of interelectrode gap in micro ECM is presented based on the capacitance of electric double layers （EDL）. On the premise that the external sensors are not added onto the microtool electrode and/or workpiece, the tendencythat the capacitance value of EDL on the tool electrode/solution interface increases monotonously with the increase of the inter electrode gap is utilized to realize the precise and quick online detection of interelectrode gap. When the interelectrode gap ranges from 0 to 100 μm under the sidestream flushing speed of 1. 058 m/s, the size of interelectrode gap in micro ECM can be detected within a few milliseconds. error between the theoretical simulation and the experimental measurements can provide the necessary conditions for the highprecision, highquality and ECM. And the maximum relative is less than 10% , which stable machining in micro