A Comprehensive Review of Non-Traditional Machining Processes

Machining has changed considerably with the arrival of advanced engineering materials. Conventional machining still handles many jobs well, but the problem starts when the workpiece is very hard, brittle, heat resistant, or geometrically complex. This is where Non-Traditional Machining (NTM) enters the picture. Instead of relying only on a cutting edge, NTM uses electrical, electrochemical, mechanical, thermal, or chemical energy to remove material. Some NTM processes uses little or no direct mechanical cutting action. This paper presents a theory-based review of major non-traditional machining processes, including Electrical Discharge Machining (EDM), Wire Electrical Discharge Machining (WEDM), Electrochemical Machining (ECM), Ultrasonic Machining (USM), Laser Beam Machining (LBM), Abrasive Water Jet Machining (AWJM), Electron Beam Machining (EBM), and Plasma Arc Machining (PAM). Their working principles, material removal mechanisms, important process parameters, advantages, limita-tions, and industrial applications are discussed. A comparative view is also given because the same machining process cannot fit every material and every geometry. Recent developments in hybrid machining, micro-machining, advanced power control, intelligent process monitoring, and sustainable manufacturing are discussed as well. Overall, the review shows why NTM remains important when conventional machining begins to reach its practical limits.