Influence of Correlation between Electrical Discharge Machining Parameters with the Formation of Surface Defect’s in Products Machined by EDM

Abstract

This paper shows a study of correlation between EDM´s parameters with the level of superficial defects development, which can lead to premature failure of die cast mold machined by EDM. The correlation of parameters was determined through experimental matrix that uses the DOE methodology (Design of Experiment). In order to evaluate the surfaces of some machined samples a stereo optical microscopy, SEM (the scanning electron microscope) and a micro hardness profile machine were used. The results show that in the worst machining condition, which is caused by association of long electric discharge pulse time-on and graphite machine-electrode, it is possible to minimize the amount of surface defects, without applying a subsequent machining process such as polishing, just using the reduced time-on´s electric discharge pulse, copper electrode and dielectric fluid with base of hydrocarbon.