An investigation on gas emission concentration and relative emission rate of the near-dry wire-cut electrical discharge machining process.

Wire-cut electrical discharge machining (WEDM) is the highly essential unconventional electrothermal machining process to cut the contour profile in the hard materials in modern production industries. The various environmental impacting contaminants (by evaporating and reacting liquid dielectric fluid) have been produced during the conventional WEDM process and are harmful to the machine operators. These wastes have been minimized by the near-dry WEDM process in which the pressurized air mixed with a small amount of water is used as a dielectric medium. In this research, influences of machining parameters (air pressure, flow rate mixing water, spark current, and pulse width) on gas emission concentration (GEC), material removal rate (MRR), and relative emission rate (RER) of near-dry WEDM process have been optimized by the Taguchi analysis. RER has been determined to analyze the variations of gas emission concentration per unit quantity of material removal by changing the process parameters. It was revealed that the maximum air pressure and flow rate of mixing water have been predicted as significant parameters on GEC and RER. While comparing wet and near-dry WEDM processes, the material removal rate of near-dry process is comparable to that of wet WEDM with minimum GEC and RER.