Analysis of electrochemical arc machining by stochastic and experimental methods

Abstract

Metal removal by a novel process, electrochemical arc machining (ECAM), is described. The mechanisms underlying ECAM, electrochemical dissolu­tion (ECD) and electrodischarge erosion (EDE) are investigated as events that occur at random in the machining gap, between the cathode tool and anode workpiece. These phases are registered as spikes of varying height and width in voltage and power recordings of the process; a stochastic method in the form of linear and nonlinear models is used to describe them. The basis of the ensuing analysis is the interpretation of model parameters in the light of physical behaviour known to arise in established electrochemical (ECM) and electrodischarge (EDM) machining. To that end, the spectral moments developed from the voltage recordings are used to discern between the phases of ECD and EDE arising in ECAM, and between the onset of sparks or arcs in the EDE-phase. The practical case of hole-drilling by ECAM is used to illustrate the main aspects of this stochastic approach: the effects of the principal machining process variables on the type, intensity and duration of the resulting ECD and EDE phases are assessed.