STUDY OF TOOL WEAR RATE OF DIFFERENT TOOL MATERIALS DURING ELECTRIC DISCHARGE MACHINING OF H11 STEEL AT REVERSE POLARITY

In this paper an effort has been made to compare the usefulness of electrode made through Powder Metallurgy (PM) in comparison with conventional copper electrode during electric discharge machining. Experimental results are presented on electric discharge machining of H11 steel in standard EDM oil with copper tungsten (75 % Cu and 25%W) tool electrode made through powder metallurgy technique and Copper electrode (99%Cu). An L18 (21 X 33) orthogonal array of Taguchi Methodology was used to identify the effect of process input parameters (viz. electrode type, peak current, voltage and duty cycle) on the output factor (viz. Tool wear rate). It was found that copper tungsten (CuW) made through powder metallurgy gives better TWR as compared to conventional electrode (Cu) and the best parametric setting for minimum TWR is with CuW powder metallurgy tool electrode, 4 ampere current, 40 volts gap voltage, 0.72 duty cycle, i.e., A2B1C1D1