Experimental investigations into die-sinking electric discharge machining of hardened AISI 6150 tool steel using different electrode materials

摘要

Electric Discharge Machining (EDM), a non-conventional machining process, is being vastly used for manufacturing tools, dies, moulds etc. Tool steels have proved to be extremely difficult-to-machine using conventional machining processes, due to heavy tool wear, incapability to produce complex shapes having better surface finish and low machining rate. Better performance of any machining process can be achieved by faster rate of metal removal, better surface finish with a reduced tool wear. The use of medium carbon chrome--vanadium alloy steel as material for trimming dies, heavy duty punches, press tools and plastic molds is becoming an increasing demand in the tooling industry due to its high strength, impact and fatigue strength at moderate hardness. The paper presents details and results of an experimental investigation into the machinability of AISI 6150 tool steel (IS Designation: T 50 Cr 1 V23, En-47), hardened and tempered to 55 HRc, using die-sinking EDM process with varying pulsed current and four different electrode materials. The process performance characteristics were studied under different machining conditions and electrode materials. Investigations indicate that the performance measures of EDM increase with the increase in pulsed current and the best machining rates are achieved by copper-tungsten electrode.