Experimental investigation of machining performance in fast hole drilling of super alloys by electrical discharge machining

Thesis Type: Postgraduate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2017


Supervisor: YAVUZ ZÜMRÜT


In this thesis, machining performance of fast hole drilling operations applied on cobalt based Stellite-6 and iron based Incoloy A-286 super alloys, commonly used in aerospace industry, were investigated experimentaly by using electrical discharge machining (EDM) method. In the experiments carried out with brass and copper electrodes; influences of most effective machining parameters, namely the discharge current, pulse on time and flushing pressure, on the performance outputs of material removal rate (MRR), electrode wear rate (EWR) and workpiece surface roughness (SR) were determined. In the Stellite-6 super alloy, all of the experiments made with brass electrode provided higher MRR values than the copper electrode, and in the majority of experiments, higher EWR and lower SR values were obtained than copper electrode. In the case of Incoloy A-286 super alloy, in most of the experiments made with brass electrode, higher MRR values were obtained than copper electrode and no significant differences were observed in EWR values between the two electrodes. Again in most of the experiments, although there are no significant differences in terms of order of magnitudes, lower SR values were obtained with copper electrode.