Experimental Characterization of Sinking Electrical Discharge Machining Using Water in Oil Emulsion as Dielectric

Abstract

Electrical discharge machining (EDM) has been wildly used in the modern manufacture industry due to its advantage over the traditional manufacture method of some hard-to-cut materials. However, compared with the traditional manufacture method, the EDM process was inefficient and environmentally hazardous due to the decomposition of the dielectrics, especially in the case of sinking EDM which used oil-based dielectric. In order to improve the EDM performance, and for the other hand, alleviate the environmental impact of the process, a new type of dielectric, water in oil (W/O) emulsion was proposed as the working fluid. This work presents a systematical study on the performance of this new type dielectric based on the orthogonal and additional single factor experiments. Statistical analysis of the results show that discharge current (I) and water content of the emulsion significantly influence the machining performance of sinking EDM. The study also analyzed the influence of the emulsion temperature and flushing condition on its EDM performance. It was observed that both MRR and EWR decrease with increasing temperature of the emulsion. Experiments results indicated that W/O emulsion can be used as the working fluid of sinking EDM and alleviated the environmental impact of the process.

Keywords:

• Dielectric
• Electro-discharge
• Emulsion
• Environmental
• Machining
• Manufacturing
• Orthogonal
• Water

ACKNOWLEDGMENTS

The work is partially supported by a grant from Chinese National Natural Science Foundation (Grant No. 50675225), a grant from Department of Science & Technology of Shandong Province (Grant No. 2006GG2204001), and the Fundamental Research Funds for the Central Universities (Grant No. 11CX04031A).

Notes

Thermal conductivity (λ), melting point (δ), specific heat (C), conductivity (ζ), viscosity (η), and density (ρ).