Effect of Powder Concentration in EDM Process with Powder-Mixed Dielectric (PMD-EDM)

Ti–6Al–4V is widely used in the aerospace, automobile, and biomedical fields, but is a difficult to machine material. Electrical discharge machining (EDM) is regarded as one of the most effective approaches to machining Ti–6Al–4V alloy, since it is a noncontact electro-thermal machining method, and it is independent from the mechanical properties of the processed material. In electro discharge machining (EDM), dielectric plays an important role during machining operation. The machining characteristics are greatly influenced by the nature of dielectric used during EDM machining. In present paper silicon powder suspended kerosene as dielectric is used to explore the influence of these dielectrics on the performance criteria such as material removal rate (MRR), tool wear rate (TWR) and surface roughness (Ra) during machining of titanium alloy (Ti-6Al-4V). Peak current, pulse on time, pulse off time and concentration of powders added into dielectric fluid of EDM were chosen as process parameters to study the PMEDM performance in terms of MRR, TWR and Ra. The experiments were carried out in planning mode on a specially designed experimental set up developed in laboratory. Response surface methodology, employing a face-centered central composite design scheme has been used to plan and analyze the experiments.