JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III UNCONVENTIONAL MACHINING PROCESSES Previous Question Paper (November/December - 2020 - R16)

Non-traditional machining processes are classified based on the primary energy source used for material removal:

• Mechanical Energy Processes: Utilize high-velocity particles or mechanical vibrations to erode material. Examples include Ultrasonic Machining (USM), Abrasive Jet Machining (AJM), and Water Jet Machining (WJM).
• Electrochemical Energy Processes: Rely on electrolytic dissolution of the workpiece material. Examples include Electrochemical Machining (ECM) and Electrochemical Grinding (ECG).
• Thermal Energy Processes: Use concentrated heat to melt or vaporize material. Examples include Electrical Discharge Machining (EDM), Laser Beam Machining (LBM), Electron Beam Machining (EBM), and Plasma Arc Machining (PAM).
• Chemical Energy Processes: Utilize chemical reagents to etch material from the surface. An example is Chemical Milling (CHM).

Recent developments in Ultrasonic Machining (USM) focus on enhancing material removal rates, surface finish, and the ability to machine complex geometries in advanced materials:

• Rotary Ultrasonic Machining (RUM): A hybrid process combining diamond grinding and ultrasonic vibrations. This significantly improves the material removal rate for brittle materials like ceramics and glass by reducing the required feed force.
• Ultrasonic Assisted Turning (UAT): Integration of ultrasonic vibration into conventional turning tools. This reduces cutting forces, improves chip breaking, and extends tool life when machining hard-to-cut superalloys.
• Micro-USM: Development of high-frequency transducers and micro-sized tools to enable the production of micro-holes and micro-features with high aspect ratios in semiconductors and brittle components.
• Advanced Slurry Systems: Research into non-aqueous slurries and nano-abrasive particles has led to better surface integrity and reduced subsurface damage in sensitive electronic materials.
• Computer-Aided Control: Implementation of real-time feedback loops to monitor tool wear and adjust vibration amplitude automatically, ensuring consistent dimensional accuracy during prolonged machining cycles.