An experimental study on electro-discharge machining and polishing of high strength copper–beryllium alloys

Abstract

An experimental study on the effect of electro-discharge machining (EDM) parameters on material removal rate (MRR) and surface quality, when machining high strength copper–beryllium alloys is presented. Processing parameters for rough, finishing and micro-finishing or polishing regimes were analysed, as well as the effect of the introduction of planetary motion and a relaxed oscillation waveform delivered by a relaxation circuit (RC) during finishing and micro-finishing cuts were studied. The surface integrity of electro-discharge machined (EDMed) is quantified by measuring the roughness values, crater diameter and white layer thickness (WLT). Quantification of the extended surface damage and its relation to the discharge power, as measured through the product of current intensity ( I) and discharge time ( t d), controllable in a isopulse type generator, is carried out. “Thermal erosion models”, as justification for the optimal setting of different EDM parameters and achievement of distinct surface integrity using materials with different thermal properties, are discussed.