Comparative Energy Consumption Analysis of Non-Traditional Machining and Conventional Machining Processes

Energy consumption has become one of the deciding criteria in modern process selection, alongside accuracy, surface integrity, and cost. Conventional machining processes such as turning, milling, drilling, and grinding remove material through direct mechanical shearing and, for machinable metals, generally consume less energy per unit volume of material removed than most non-traditional machining (NTM) processes. Non-traditional processes such as Electrical Discharge Machining (EDM), Electrochemical Machining (ECM), Laser Beam Machining (LBM), Ultrasonic Machining (USM), and Abrasive Water Jet Machining (AWJM) rely on thermal, electrochemical, chemical, or high-energy-beam mechanisms that are frequently far less efficient in a strict energy-per-volume sense, yet they remain indispensable for hard, brittle, heat-sensitive, or geometrically intricate materials that conventional cutting simply cannot process economically or at all. This paper reviews the physical basis of energy consumption in machining, compares the specific energy consumption (SEC) of representative conventional and non-traditional processes, and examines the auxiliary, idle, and process-specific loads that shape total energy demand. A comparative framework is presented, supported by findings drawn from recent literature on wire-cut EDM energy optimisation, plasma-assisted machining, and electrochemical processes. The paper concludes that energy consumption cannot be judged in isolation from material removal rate, achievable tolerance, and material machinability, and that a genuinely sustainable process selection strategy must weigh energy cost against these functional requirements rather than treating specific energy consumption as a stand-alone metric.