A Critical Review on Recent Advances and Sustainability Challenges in EDM of Advanced Materials

ABSTRACT: Electrical discharge machining (EDM) remains indispensable for high-precision machining of advanced and hard-to-machine materials; however, its broader industrial adoption is constrained by high energy consumption, unstable discharge behavior, dielectric degradation, and limited integration of sustainable and intelligent manufacturing strategies. Although existing reviews address micro-EDM and environmentally benign EDM individually, a consolidated and critical synthesis linking discharge physics, sustainability bottlenecks, and intelligent process control has remained limited. This review systematically analyzes highly cited and recent studies (2020–2024) indexed in Scopus and Web of Science, focusing on micro-EDM, green dielectric systems, hybrid-assisted EDM, and intelligent EDM technologies. The synthesized literature identifies key bottlenecks, including deterioration of the inter-electrode environment, inefficient debris evacuation, dielectric decomposition, and the absence of standardized sustainability performance metrics. The analysis reveals a clear convergence toward hybrid-assisted, sustainability-driven EDM strategies, in which coupled plasma–thermal–chemical interactions govern material removal and surface integrity rather than purely thermal effects. Comparative findings indicate that ultrasonic assistance is most effective for micro-scale and brittle materials, magnetic field assistance enhances plasma stability in conductive metallic systems, and biodegradable or water-based dielectrics significantly reduce environmental impact while maintaining acceptable machining performance. Furthermore, intelligent EDM approaches integrating sensor-based monitoring, AI-assisted optimization, and digital-twin frameworks show strong potential for adaptive control, although industrial deployment remains limited by sensing robustness and system integration challenges. Overall, this review proposes a structured roadmap for transitioning EDM toward intelligent, energy-efficient, and sustainable industrial manufacturing.