Experimental Investigation to Determine Influence of Process Parameters on Surface Finish and Mrr in Wire Cut Edm

Abstract

Wire Electric Discharge Machining (WEDM) is one of the greatest innovations in the tooling and machining industry. This process has brought dramatic improvements in accuracy, quality, productivity and earnings. Before wire EDM, costly processes were often used to produce finished parts. Now with the aid of computer and wire EDM machines, extremely complicated shapes can be cut automatically, precisely and economically even in materials as hard as carbide. The selection of optimum machining parameters in WEDM is an important step. Improperly selected parameters may result in serious problems like short-circuiting of wire, wire breakage and work surface damage which is imposing certain limits on the production schedule and also reducing productivity.

The objective of the present work is to investigate the effects of the various Wire cut EDM process parameters on the surface quality, maximum material removal rates and obtain the optimal sets of process parameters so that the quality and MRR of machined parts can be optimized. Experiments are conducted on the Aluminum alloy 7475 pieces by varying parameters. The process parameters varied and their respective values are Pulse Time on - 100µsec, 110 µsec, 120 µsec & Pulse Time off – 52 µsec, 56 µsec, 60 µsec, Servo Voltage – 20V, 30V, 40V and Wire Feed – 2mm/min, 3mm/min, 4mm/min. Other parameters are kept constant such as Wire diameter - 0.25mm, Peak Current – 1.1Amp, Coolant is Distilled water, Wire Tension – 7Kgf. The optimization is done by using Taguchi technique considering L9 orthogonal array. Optimization is done in Minitab software.