The influence of working parameters and size effect on surface roughness during EDM process

This paper presents an investigation into the influence of working parameters and size effect of electrode upon SKD61, SKD11 and 304L. Surface topography, surface roughness are discussed to evaluate the quality of EDMed surface. When working parameters are taken into consideration, surface roughness will be deteriorated as pulse current and pulse-on duration increased. An equation can be further regressed as Ra=0.5∗Ip^0.45∗τON^0.2. When working parameters are fixed, surface roughness remained almost the same as machined with variable working materials. In aspect of size effect, the observation of the surface topography shows that the size effect does not affect the shape of crater. At the same time, surface roughness is not variable with the capacity induced by size effect. The result reveals that pulse current and pulse-on duration should be lowered in order to get a better surface integrity. Meanwhile, when the equivalent current is smaller than the pulse current, the capacity induced by size effect can be omitted.