An Experimental Study on the Effect of Primary Cavity Depth on Surface Integrity of Tool Steel (DIN 1/2379) in EDM Process

In this paper¡ the effect of the primary cavity depth in different input parameters (pulse duration and spark current)¡ in the Electrical Discharge Machining(EDM) on surface integrity(white layer thickness¡ HAZ¡ micro hardness and micro crack density) of DIN 1.2379 cold work tool steel has been studied. According to the obtained results¡ increasing the initial depth of hole¡ decreased the white layer thickness¡ micro crack density on the Machined surface and HAZ. The results of the micro hardness also¡ indicate growth the value of hardness in the layers close to the machined surface along the depth and after passing through a specified depth from machined surface¡ this process stopped and then¡ the machined surface micro hardness reduced.