Investigation effects of process parameters on material removal and surface quality in electrical discharge machining

Electric disharge machining (EDM) method is a nonconventional manufacturing method widely employed in mold manufacturing industry, automotive, aircraft and the aerospace indusrty base on the material removal through the effect of a series of rapid and repetitive electirical discharges between the electrode and the workpiece immersed into the dielectic fluid. Many researches have been conducted until present to determine the effects of processing parameters in the electro disharge machining method. In this research, the effects of the most efficient process parameters such as discharge current, pulse on time and pulse off time on outcomes of processing performance such as material removal rate ( MRR), electrode wear rate (EWR), surface roughness of workpiece, surface roughness of electrode and electrode edge wear have been examined through utilization of % 99,99 pure copper electrodes with different diameters in electrical discharge machining of materials from cold work tool steel TS EN X155CrVMo12 (DIN 1.2379) Moreover, the effect of energy density in electro-discharge machining that has not been addressed in detail in the previous researches has also been examined. Process parameters which have more significant impact on the outcomes of processing performance have been determined through the Application of Analysis of Varience (ANOVA) method. The results have also been optimized by applying the Taguchi experimental design and the accuracy of the optimized values have been evaluated by the implementation of a verification test. As a result of the experimental studies, material removal rate, electrode wear rate, workpiece surface roughness, electrode surface roughness and edge wear of the electrode have increased with increasing discharge current. Material removal rate, workpiece surface roughness and edge wear of the electrode values have increased with the increase of pulse on time. Electrode wear rate has decreased with increasing pulse on time under test conditions where discharge current was 9 A and 15 A while under test conditions where discharge current was 21 A and pulse off time was (30, 300 µs) in increased pulse on time was found to cause an increase in the amount of electrode wear. It was observed that pulse on time had less effect on the electrode surface roughness and MRR, EWR and electrode edge wear values decreased with increasing pulse off time. It was observed that pulse off time had less effect on workpiece surface roughness and electrode surface roughness. It was determined that material removal rate, workpiece surface roughness and electrode edge wear values increased with the increase in energy density. Key words: Electric Discharge Machining, material removal, energy density, taguchi, ANOVA