EFFECTS OF FLUSHING ON ELECTRODISCHARGE MACHINED SURFACES

Although the influence of flushing on the efficiency and stability of machining conditions in EDM has been extensively investigated, includi ng the effects of the flushing configuration on the wear of the tool a nd the profile of the workpiece, little has been reported concerning t he effects of flushing on the integrity of the electrodischarge machin ed (EDMed) surfaces. This paper presents the effects of flushing rates on the types and distribution of recast layers in commercially pure i ron, 0.5% C steel and AISI 01 tool steel after EDM. There exists an op timal dielectric flushing rate where cracks and average thickness of t he recast layer are at a minimum for all three materials. The trends f or the crack density and recast thickness are similar, being higher at flushing rates below and above a basically similar optimum rate. The distributions of the crack density at the sides, bottoms acid corners of the machined cavities under different flushing conditions are prese nted. Based on the results obtained, the effects of the quenching prop erty and debris removal ability of the dielectric flow conditions on t he recast layers of the three types of EDMed specimens are discussed.