Study of Correlation of Machining Performance and Geometrical Tolerances of Si3N4-TiN Composites Using EDM Process

The aim of this research work is to enhance the machining characteristics and geometrical tolerances of Si 3 N 4 –TiN ceramic composite using a copper electrode as the EDM tool. The investigation encompassed a comprehensive exploration of various machining parameters, including polarity, current (amp), pulse on time (µs), pulse off time (µs), dielectric pressure (Kg/cm 2 ), gap voltage (v), spark gap (mm), and servo speed (m/s), utilizing a Taguchi L 18 orthogonal array. Throughout the EDM process, meticulous scrutiny was applied to output characteristics such as Material Removal Rate (0.0354 gm/min), Tool Wear Rate (0.001035 gm/min), Wear Ratio (22.625), Surface Roughness (0.117 µm), Top Radial Overcut (0.043 mm), Bottom Radial Overcut (-0.214 mm), top diameter of the drilled hole (5.087 mm), bottom diameter of the drilled hole (4.572 mm), Taper Angle (0.458 deg), Circularity (0.039 mm), Cylindricity (0.034 mm), Perpendicularity (0.007 mm), and Run Out (0.036 mm). The higher pulse current promotes the formation of a stable plasma channel which results in increasing the material removal rate. The improved flushing action helps to minimize the recast layer, leading to a smoother surface finish and reduced surface roughness. The experimental results demonstrate that as the spark gap increases from 0.18 mm to 0.25 mm, the Runout, Electrode Wear Rate, ROC Bottom, ROC Top, and Taper Angle drastically reduce.