Influence of Machining Parameters on Electric Discharge Machining of Maraging Steels - An Experimental Investigation

Electric discharge machining is categorized as a thermoelectric process in which heat energy of spark is used to remove material from the work piece. The machining process involves controlled erosion of electrically conducting material by the initiation of rapid and repetitive electrical spark discharges between the tool and workpiece separated by the dielectric medium. The present work is aimed at characterizing the electric discharge machining of maraging steels on EDM. 27 experiments are conducted by varying EDM parameters such as current, pulse-on-time, and duty factor. The performance measures like Material removal rate, surface roughness, and hardness are assessed. It is concluded that metal removal rate, and surface roughness increases with increase in current, duty factor. But, as the pulse-on-time increases MRR and surface roughness decreases. Hardness value increases as the current value increases from 5A to 10A amps and then decreases as the current increases from 10A to 15A. The same effect is observed as in case of duty factor and pulse on-time. Average crack length and recast layer thickness increases with increase in current and duty factor. But, there will be decreasing trend in case of pulse-on-time. is delivered to the electrode at a frequency of several KHz producing sparks of similar frequency between the electrode and the work piece through the dielectric fluid. Intense heat is created in the localized area of spark impact, the metal melts or even vaporizes and gets expelled from the surface of workpiece. The dielectric fluid, which is constantly being circulated, carries away the eroded particles of metal during the off cycle of the pulse and also assists in dissipating the heat caused by the spark.