A comprehensive review of process mechanisms, electrolyte effects, parameter optimization, and industrial applications on traveling wire electrochemical discharge machining (TW-ECDM)

Traveling wire electrical discharge machining (TW-ECDM) is an effective micromachining process for non-conductive and brittle materials such as ceramics, quartz, and composites. It combines electrochemical discharge machining with a moving wire electrode, offering high precision, reduced tool wear, and greater machining flexibility compared with conventional methods. This review examines the engineering principles of TW-ECDM, including gas film formation, spark generation, thermal erosion, electrochemical reactions, and material removal mechanisms. Key process parameters, including applied voltage, electrolyte type and concentration, wire material, wire feed rate, and auxiliary techniques such as ultrasonic vibration, magnetic fields, and abrasive-mixed electrolytes, are discussed in relation to material removal rate, kerf width, surface quality, and process stability. Recent developments include zinc-coated brass wire electrodes, abrasive-mixed electrolytes, ultrasonic assistance, magnetic-field-assisted machining, multi-physics modeling, and artificial intelligence-based process optimization. The literature indicates that optimized alkaline electrolytes and hybrid-assisted TW-ECDM systems can enhance machining capability and discharge stability while improving dimensional accuracy. However, gas-film instability, wire degradation, dimensional accuracy, surface integrity, environmental sustainability, and industrial scalability remain major challenges limiting wider adoption. Future research should focus on smart process monitoring, machine-learning-based adaptive control, sustainable electrolyte systems, advanced wire electrode technologies, and digital-twin-based process modeling. Overall, this review provides a comprehensive assessment of TW-ECDM and highlights its potential as an intelligent, sustainable, and versatile micromachining technology for advanced non-conductive materials.