A Study on Effect of Powder on EDM (PMEDM)

Abstract

EDM is a non- conventional machining process for removing material from workpiece using erosive effect.an arc is produced between electrode and tool, both must be electrically conductive. There is no direct contact between tool and workpiece. It is effective in machining hard materials, materials such as heat resistant alloys, super alloys and carbides which can?t be easily machined with conventional method. It is widely used in mould, die making industry and in manufacturing of automotive, aerospace surgical components. Besides its advantages EDM have some drawbacks such as less material removal rate and poor surface finish. To overcome these drawbacks the metallic powder is mixed in the dielectric fluid, which increases its conductive strength and increases the spark gap distance between the tool and workpiece. This new evolved material removal process is called Powder mixed EDM (PM-EDM).For the purpose of experimentation D3 die steel as a workpiece with copper electrode as a tool and DEF-92 oil as dielectric has been used. PMEDM is very complex in nature and controlled by a large number of parameters, which are having impact on various responses. The present study is an attempt to investigate the potential of PMEDM for increasing material removal rate (MRR), decrease in tool wear rate (TWR) with improved surface roughness (SR) of Die steel. In previous research work Kerosene is used as dielectric fluid. Kerosene has adverse impact on the environment as well as health of the operator. So in this experimental method commercially available EDM oil will be used. The research outcome will identify the important parameters and their effect on material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) in the presence of suspended powder in a DEF-92 oil as dielectric of EDM. Experiments is designed using Taguchi method so that effect of all the parameters could be studied with minimum possible number of experiments .Results of the experimentation is analyze analytically as well as graphically using ANOVA and main effect-interaction plots, respectively. ANOVA has determined the percentage contribution of all factors upon each response individually.