Influence of heat-treated Cu-Be electrode on machining accuracy in ECMM with Monel 400 alloy

Monel 400 is a nickel-copper alloy utilized in marine and oil refining industries owing to its high corrosion resistance and fire withstanding property. The machining of such higher strength material with complex shapes is possible with electrochemical micromachining (ECMM) process, since it can machine with less wear, better precision, micro-level hole profiles, no heat-affected zone and no thermal stresses. The present study was performed with machining of Monel 400 alloy in ECMM process with copper-beryllium wire electrode under various heat treatments, such as annealing, quenching and normalizing. The lower overcut can be obtained using quenched tool electrode when compared to the other treated tools and untreated tool electrode owing to its fine grain structure which restricts the flow of electrons to side of the tool. The conicity with normalized tool electrode is lower, since it exhibits high electrical conductivity by decreasing the distraction of electrons. Circularity with quenched tool electrode is lower due to its fine grain structure and higher electrical conductivity, since its localization effect increases causing uniform stray current.