IDENTIFICATION OF INTERELECTRODE GAP SIZES IN PULSE ELECTROCHEMICAL MACHINING

Pulse electrochemical machining offers significant improvements in dim ensional accuracy as compared with conventional electrochemical machin ing. One primary issue in pulse electrochemical machining is to identi fy and control the interelectrode gap size. This paper presents an ide ntification method for the gap size by in-process analysis of machinin g current pulses. Stochastic modeling and analysis of the current puls es reveal two gap indicators: pulse signal variance and damping ratio. The variance has a linear relationship with the gap size within a com monly used gap-range of 0.10 to 0.20 mm for a wide range of pulse dura tions. The damping ratio has been found to be highly correlated with t he gdp size. Laboratory experiments confirm the feasibility of this me thod under unevenly distributed gap conditions; The process mechanism underlying these findings is also discussed.