Modeling of Machining Characteristics and Tool Shape in Electrical Discharge Machining using Composite Tool Tip

Abstract

Electrical Discharge Machining (EDM) is a non-conventional and non-contact type of machining process in which metal is eroded by thermo-electrical properties of tool and workpiece when sparks are applied in between tool and workpiece under the dielectric medium. Apart from all benefits, it can’t be said that EDM process is free from limitations. Tool wear rate is the critical problem among all other problems which ultimately impacts the shape of tool. In the current research, the surface morphology and the machining characteristics such as tool wear rate, material removal rate, out of roundness and surface roughness have been studied by creating the semi-empirical model with help of dimensional analysis and process parameters i.e. discharge current, pulse-on time, pulse-off time. Here, there is use of ceramic tool tip of copper titanium carbide which is fabricated by following powder mixing, compacting and sintering, in comparison with simple copper tool for machining H13 tool steel workpiece. The experiments have been performed by both the tools i.e. copper and copper-titanium carbide. Then, the semi-empirical model for the Cu-TiC tool machining is evaluated which is compared with its statistical model. The surface morphology has been done for studying the surface integrity of workpiece material after machining by both the electrode tools. The deformities like cracks, debris, pores, white cast and recast layer are found to be less in workpiece surface machining by simple copper tool as compared to the machining by Cu-TiC ceramic tool. The less TWR and high MRR are found with use of Cu-TiC ceramic tool as compared to simple Cu tool.