Modelling of Surface Roughness in Coated Wire Electric Discharge Machining through Response Surface Methodology

Electric Discharge Machining (EDM) has been used for machining of electrically conductive difficult materials and Wire EDM is a kind of EDM where a wire is used as the tool and machining takes place due to erosion. Usually, Copper and brass wires were effectively used for machining in WEDM but it was found that the productivity and characteristics for coated wires had better results hence zinc coated wires will be used. The study has been conducted for the modelling of a WEDM process performed on the Tool Steel EN31. Surface Roughness (SR) is the major performance characteristic that is evaluated. The corresponding parameters acting as the input are Current, Pulse on Time and Pulse off Time, Wire Tension. The central composite design is utilized to plan the experiment and Response Surface Methodology is implied and an experimental model has been developed. Analysis on machining characteristic of coated WEDM is made based on the developed model. The model has been verified and checked for adequacy.