The Research Of Intelligent Measuring And Controlling Interelectrode Gap Of Electrochemical Machining (ECM)

In electrochemical machining (ECM), interelectrode gap is a key technical pa-rameter. It is influenced by electromagnetism, electrode polarization and electro-lyte's temperature, consistence, pressure and so on. So inter-electrode gap is the in-tegration of physical and chemical factors in processing, and it's variation will di-rectly determine the machining precision, efficiency and surface quality, it is always the mainly basis of designing cathode and choosing machining parameters. A good method has not been found to resolve copying error, repeated error and uncontrolla-ble machining process resulted by instable variation of interelectrode gap at present. How to on-line monitor and control the gap in effect has been the key difficult problem that ECM experts and scholars want to settle all the time.Based on forces and machining currents, intelligent on-line monitoring and controlling the interelectrode gap is realized on the dissertation Surported by NSFC,. The relation among forces received by cathode, machining currents and interelec-trode gap is investigated widely and deeply, and six new kinds of interelectrode gap control method is presented based on this relation.Firstly, the theoretical relation between machining currents and forces received by cathode from electrolyte and interelectrode gap is researched. A new ECM model based on capacity is proposed,and the equation between forces and interelectrode gap is set up, it offers the theory basis for the following experiments.For experiments, The machining experiments using two kinds of cathode pro-file such as plane and blade surface are researched. The force, machining currents and the interelectrode gap is measured during the test.The acquiring datum are processed by wavelet and wavelet package transform to avoid the effect of noise, it is found that the machining currents and forces be-come large while the interelectrode gap decrease, this relation between machining current, forces and inter-electrode gap is used to train a BP Neural Network. So that the interelectrode gap can be predicted on-line by the trained Neural Network and the acquired currents and forces on-line, and it can also be used in the intelligent control of interelectrode gap.The signals gained from above two kinds of sensors show a different charac-teristic after wavelet transform, in order to make a better interelectrode gap control, the machining current and forces are fused by the technology of Neural Network...