Tribological study of metallic surfaces produced by EDM

Electric discharge machining is becoming widely used as atechnique for metal cutting particularly when hard metals orcomplex shapes are invol ved. However not enough is yet knownabout the surface characteristics and obtained accuracy of theprocess. Therefore the main problem associated with EDM, is howto obta i n the requ i red accuracy of shape and d j mens i on for acertain workpiece. This problem can be solved when contro11 ingthe operating parameters of the process.The experimentalwork of this study was carried onelectrospark machine type ’CV.J. K. 5) using commercial keroseneas a dielectric for all the machined specimens. The dischargecurrent and pulse frequency were used as controlling variables.Two types of workpiece materials were used steel and Inconel-718, while copper and graphite were used as tool materials.The obtained results showed that the use of low values ofdischarge current and higher values of pulse frequency, gave~tter surface quality, and this is generally attributed to thelow spark energy associated with such conditions.The influence of the working variables on the subsurfacelayer characteristics was also studied. The results showed thatsome m i crocracks appeared in th i slayer when all va I ues ofdischarge current were used.A part of study was aimed to find the influence of the