My M.Tech thesis, Investigation of Sustainable Electro Discharge Machining Process, explores the possibility of transforming the traditional EDM process into an environmentally responsible and high-performance machining technique. EDM is widely used for machining difficult-to-cut materials like Ti-6Al-4V, but the conventional hydrocarbon dielectrics used in EDM generate toxic fumes, create disposal challenges, and have poor biodegradability. Recognizing these limitations, my research examines the use of Jatropha bio-oil and biodiesel as sustainable dielectric fluids, comparing their machining performance with standard EDM oil. The study systematically evaluates how these green dielectrics influence spark behaviour, thermal characteristics, crater formation, surface finish, and tool wear, thereby developing a more sustainable EDM process without compromising precision, efficiency, or quality.

Objectives

✔ To evaluate the suitability of bio-oil and biodiesel as sustainable dielectric fluids

✔ To analyse the influence of dielectric type on critical machining responses

✔ To study the thermal and morphological characteristics of EDM-machined surfaces

✔ To determine the statistical significance of process parameters using Taguchi and ANOVA methods

✔ To assess the overall feasibility of adopting bio-fluids for industrial EDM applications

Key Findings & Conclusions

The findings of this thesis clearly demonstrate that bio-oil and biodiesel are technically viable and environmentally superior alternatives to conventional EDM oil for machining Ti-6Al-4V. Throughout the experimental study, the bio-based dielectrics consistently exhibited more stable spark behavior, enhanced cooling and flushing, and improved dielectric strength, all of which contributed to smoother machining performance. The improved flushing characteristics of bio-fluids helped remove debris more efficiently from the spark gap, reducing the likelihood of arcing and leading to more uniform discharge conditions. As a result, the machining process became more stable, resulting in higher material removal rates and reduced tool wear when compared to traditional hydrocarbon-based EDM oils.

The surface integrity outcomes also highlighted the advantages of sustainable dielectric fluids. Surfaces machined with bio-oil and biodiesel displayed smoother crater geometry, fewer micro-cracks, and a more uniform re-solidified layer, as confirmed by SEM micrographs provided in the thesis. These observations indicate that bio-fluids moderate the thermal load on the workpiece more effectively, thereby reducing thermal damage and improving the surface finish. The reduced carbon deposition and cleaner crater outlines further reinforce the superior thermal characteristics of these renewable dielectrics.

From a process-parameter perspective, the statistical analysis using Taguchi design and ANOVA revealed that pulse ON time and peak current are the most influential factors governing machining performance across all dielectric environments. Their dominance in determining MRR, TWR, and Ra underscores the importance of controlling energy input per spark when machining with sustainable fluids. The optimized parameter combinations identified through statistical modeling offer practical machining windows for industries that intend to adopt bio-based dielectrics without compromising productivity.

Overall, this research concludes that bio-oil and biodiesel can successfully replace conventional EDM oil while offering clear environmental and operational advantages. The study validates that sustainable dielectrics not only reduce ecological impact and improve operator safety but also enhance machining efficiency and surface quality. The work provides a strong scientific foundation for transitioning EDM toward greener, cleaner, and more responsible manufacturing practices, especially for high-performance alloys like Ti-6Al-4V where EDM is indispensable.