Study Gas Film Formation Through the Current Signal in Electrochemical-Discharge-Machining (ECDM) with and Without a Magnetic Field

Electrochemical discharge machining (ECDM) is a hybrid advanced micromachining process known for nonconductive materials. In this process, material removal mainly occurs through the melting of the workpiece due to the electrochemical discharge at the tool electrode and high-temperature chemical etching through OH radicals in the electrolyte. The behavior of electrochemical discharge directly impacts the material removal rate (MRR) and surface quality of a machined surface. The stable gas film around the tool electrode is an essential parameter for quality discharge. Gas film formation in the ECDM process has been studied many times through recorded voltage signals and recorded high-speed images during machining. However, the repeatability of the process still needs to be controlled. The effect of input parameters on spark discharges with and without a magnetic field was examined in the present study through current and voltage signals in different parametric conditions to explore the phenomenon of gas film formation and stability. It is deduced from the current signal output that the gas film formation time and stability vary with the input voltage, duty cycle, and magnetic field. The effect of gas film stability and spark discharge consistency on surface quality is also discussed in this article.