Processing of Al2O3–SiCw–TiC ceramic composite by powder mixed electric discharge grinding

Abstract

The machining of conductive alumina ceramic was successful by the electric discharge grinding (EDG). Therefore, the aim of the present work is to increase the material removal rate (MRR) during EDG of conductive alumina ceramic by addition of ceramic powder with dielectric.

To achieve the objective through experimental investigation is carried out and the influence of input process parameters (powder concentration, duty ratio, pulse on time, table speed and wheel speed) on surface roughness (SR), MRR and surface integrity has been studied. The fine grade silicon carbide powder of #1000?mesh sizes was mixed in dielectric medium with varying concentration to understand the influence of the powder concentration and its interaction with other process parameters during powder mixed electric discharge grinding (PMEDG). The central composite rotatable design (CCRD) has been used to plan the experiments. Optimization of the obtained statistical models of MRR and SR has been done to obtain highest MRR and lowest SR.

It was observed that the MRR achieved by PMEDG was 3 – 10 times higher than EDG. It was found that all the process factors and interactions show significant contribution on SR. The SR obtained by PMEDG was 2 – 4 times higher than EDG.

It has been established that the PMEDG process is a better option for processing of Al₂O₃–SiC_w–TiC ceramic material as preliminary operation before EDG to achieve high MRR. In the present work the surface and subsurface damages were also assessed and characterized by the scanning electron microscope (SEM).