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Byline: B.R. Sarkar, B. Doloi, B. Bhattacharyya Electrochemical Discharge Machining (ECDM) process has great potential to machine electrically non-conducting engineering ceramics and can be applied for micro-machining operation. This research paper includes the experimental investigation to study the range of the parametric setting for micro-machining operation as well as the effect of various process parameters such as applied voltage, electrolyte concentration and inter-electrode gap on Material Removal Rate (MRR), Radial Over-Cut (ROC) and Heat Affected Zone (HAZ) thickness during micro-drilling of non-conducting engineering ceramic materials such as Aluminium Oxide and Zirconium Oxide. The experiments have been performed using electrolyte of KOH and NaOH salt solution. In this paper, an experimental investigation has been made to find out the optimum value of ECDM process parametric conditions for higher MRR, lower overcut and also lower HAZ thickness during micro-drilling on ceramics. The quality of the hole during micro-drilling greatly depends on the applied voltage and electrolyte concentration.

Abstract: The low wear resistance of electrodes like Cu, Cu alloys and graphite is a major problem for electrical discharge machining (EDM) operation. Here an attempt has been made to develop a metal matrix composite (ZrB2–Cu) to get an optimum combination of wear resistance, electrical and thermal conductivity. The ZrB2–Cu composite have been developed by adding different amounts of Cu and tested as a tool material at different process parameters of EDM during machining of mild steel. The ZrB2–40wt.% Cu composite shows more metal removal rate (MRR) with less tool removal rate (TRR) than commonly used Cu tool. But the diameteral overcut and average surface roughness are found to be lesser in case of Cu tool than composite tool. The tools and workpiece surfaces are analyzed by scanning electron microscope (SEM)/EDS and XRD technique. [Copyright &y& Elsevier]

The electrochemical discharge machining (ECDM) process has a potential in the machining of silicon nitride ceramics. This paper describes the development of a second order, non-linear mathematical model for establishing the relationship among machining parameters, such as applied voltage, electrolyte concentration and inter-electrode gap, with the dominant machining process criteria, namely material removal rate (MRR), radial overcut (ROC) and thickness of heat affected zone (HAZ), during an ECDM operation on silicon nitride. The model is developed based on response surface methodology (RSM) using the relevant experimental data, which are obtained during an ECDM micro-drilling operation on silicon nitride ceramics. We also offer an analysis of variance (ANOVA) and a confirmation test to verify the fit and adequacy of the developed mathematical models. From the parametric analyses based on mathematical modelling, it can be recommended that applied voltage has more significant effects on MRR, ROC and HAZ thickness during ECDM micro-drilling operation as compared to other machining parameters such as electrolyte concentration and inter-electrode gap. [ABSTRACT FROM AUTHOR]

Abstract: During machining of metals by electrical discharged machining (EDM) process a large amount of heat is generated for which the surface characteristics of the metals are affected. But this phenomenon is unavoidable during the machining of metals by EDM process and some technical problems remain unsolved in the area of surface integrity of the machined workpiece. The present study emphasizes the features of the development of comprehensive mathematical models based on response surface methodology (RSM) for correlating the interactive and higher-order influences of major machining parameters i.e. peak current and pulse-on duration on different aspects of surface integrity of M2 Die Steel machined through EDM. The paper also highlights the various test results that also confirm the validity and correctness of the established mathematical models for in-depth analysis of the effects of EDM process parameters on surface roughness (SR), average white layer thickness (WLT) and surface crack density (SCD). The detailed analyses of the SEM micrographs and the graphs plotted on the basis of experimental results also reveal the correctness of the developed mathematical models. Further, optimal combination of these parameters has been evaluated and it can be used in order to minimize various criteria of machined surface integrity. [Copyright &y& Elsevier]