PARAMETRIC EFFECTS AND ANALYSIS OF ELECTRO-DISCHARGE MACHINING OF TI-6AL-4V TITANIUM ALLOY

Abstract

The present experimentation focused on investigating electro-discharge machining performance such as material removal rate, surface roughness, electrode wear, overcut, and hardness during machining of biomedical titanium alloy Ti-6Al-4V. Taguchi L25 array is used to determine the process input parameters combination for conducting the experiments. The process input parameters are pulse current, gap voltage, pulse on-time, and pulse off-time. The response surface methodology is used for mathematical modeling. Parameters are selected so uniquely that the properties of the machined components are affected dimensionally significantly less, at the same time rate of production is also reasonably high. The mathematical models are found to be satisfactory. After performing the extensive experimentations, the effect of specific parameters and microstructure was studied and analyzed. Electric-discharge machining of Ti-6Al-4V with precise control over individual response characteristics is simple. However, achieving simultaneous control on all performance characteristics (MRR, SR, EW, OC, and H) is complex. Microstructural analysis reveals that the surface texture of the machined impressions contains a relatively high proportion of black spots. These black spots produce a coarser surface having surface roughness value, Ra = 9.735 µm at 21 Amp pulse current, gap voltage 60 Volt, pulse on-time 350 µs, and pulse off-time 175 µs. However, the material removal rate is maximum at 0.086 mm3/min at these parameters. Dimensional accuracy in overcut OC is 0.118 µm with electrode wear of 0.0006 mm3/min, and alteration in the surface hardness is about 10 VH.