Non-Conventional Machining Processes: EDM, ECM, LBM, EBM, USM, PAM

Posted on Feb 24, 2026 in Electromechanical Engineering

Part A — Section A Answers

i. Electrolyte is used in electric discharge machining.
👉 False

ii. Dielectric is used in EDM (Electric Discharge Machining) process.

iii. Full form of LASER:
👉 Light Amplification by Stimulated Emission of Radiation

iv. Full form of TPM:
👉 Total Productive Maintenance

v. For precise and narrow cutting which machining process is suitable?
👉 Laser Beam Machining (LBM)

vi. Non-conducting material can be machined in EDM.
👉 False

vii. Name any shielding gas used in arc welding.
👉 Argon (or Helium)

viii. In USM high-frequency vibration is in the range of
👉 20 kHz to 40 kHz

ix. In AJM a mixture of high-pressure air (or gas) and abrasive particles is used for machining.

x. Hidden arc welding is also known as
👉 Submerged Arc Welding (SAW)

xi. What are 5S in TPM?
👉 Seiri, Seiton, Seiso, Seiketsu, Shitsuke

xii. Electrochemical grinding is a combination of two processes:
👉 Electrochemical machining and Grinding

xiii. Which machine is suitable for making tools and die?
👉 Electric Discharge Machine (EDM)

xiv. In which machining process is a spark generator used?
👉 EDM

Non Conventional process

Non-Conventional Machining Processes

Definition

Non-conventional machining processes are those machining methods in which material removal is carried out using mechanical, thermal, electrical, chemical or electrochemical energy, without direct-contact cutting tools as used in conventional machining.

Need of Non-Conventional Machining

Non-conventional machining is required because:

1. Conventional machining cannot machine very hard materials.
2. It is difficult to machine complex and intricate shapes.
3. Very high tool wear occurs in conventional processes.
4. Conventional methods cannot machine brittle materials effectively.
5. There is a need for micro-machining and high precision.
6. There is a requirement of no cutting force in some applications.
7. Requirement of high surface finish and accuracy.

Advantages of Non-Conventional Machining

Any seven advantages include:

1. Can machine very hard materials.
2. No cutting force on the workpiece.
3. Complex and intricate shapes possible.
4. High dimensional accuracy.
5. Good surface finish.
6. Suitable for micro and precision machining.
7. Minimal tool wear.
8. Burr-free machining.
9. Can machine brittle materials.

Processes: EDM ECM EBM LBM USM PAM CHM

Instruction (corrected): EDM, ECM, Chemical Machining (CHM), EBM, LBM, USM, PAM — explain the above processes: definition, working principle, neat sketch/diagram, 7 applications, 7 advantages and 7 disadvantages. Differentiate conventional and non-conventional machining for all the above processes (as per 10 marks).

Ans: EDM — Electric Discharge Machine

EDM — Definition

EDM is a non-traditional machining process in which material is removed from an electrically conductive workpiece by a series of controlled electric sparks between the tool and workpiece submerged in dielectric fluid.

EDM — Working Principle

• Tool and workpiece are connected to a DC power supply.
• A small gap (spark gap) is maintained between them.
• Dielectric fluid breaks down and produces sparks.
• Each spark melts and vaporizes material from the workpiece.
• Molten metal is flushed away by the dielectric.

EDM — Applications (Any 7)

1. Die and mould making
2. Tool manufacturing
3. Drilling micro holes
4. Aerospace components
5. Automobile parts
6. Hard material machining
7. Medical instruments

EDM — Advantages (7)

1. Machines very hard materials
2. No cutting force
3. High accuracy
4. Complex shapes possible
5. Burr-free machining
6. Good surface finish
7. Suitable for intricate cavities

EDM — Disadvantages (7)

1. Only conductive materials can be machined
2. Low material removal rate (MRR)
3. Tool wear occurs
4. High power consumption
5. Expensive equipment
6. Heat-affected zone
7. Dielectric handling needed

ECM — Electrochemical Machining

ECM — Definition

ECM removes material by electrochemical dissolution using an electrolyte and DC power supply.

ECM — Working Principle

• Workpiece is the anode (+).
• Tool is the cathode (−).
• Electrolyte flows between them.
• Metal ions dissolve from the workpiece.
• No spark or heat generation.

ECM — Applications (7)

1. Turbine blades
2. Aerospace parts
3. Complex cavities
4. Gear machining
5. Thin wall components
6. Medical implants
7. High-precision parts

ECM — Advantages (7)

1. No tool wear
2. No thermal damage
3. High surface finish
4. No cutting force
5. Burr-free surface
6. High accuracy
7. Fast machining

ECM — Disadvantages (7)

1. Only conductive materials
2. High initial cost
3. Electrolyte disposal problems
4. Complex setup
5. Power consumption
6. Corrosion risk
7. Environmental issues

CHM — Chemical Machining

CHM — Definition

Chemical machining removes material by controlled chemical etching using suitable etchants.

CHM — Working Principle

• Surface is masked except the machining area.
• Chemical etchant is applied to the unmasked area.
• Unmasked area dissolves.
• Mask is removed after machining.

CHM — Applications (7)

1. Printed circuit boards
2. Thin sheets
3. Decorative designs
4. Aerospace panels
5. Name plates
6. Engraving
7. Electronic components

CHM — Advantages (7)

1. No mechanical stress
2. Low tooling cost
3. Uniform material removal
4. Complex shapes possible
5. No heat-affected zone
6. Suitable for thin parts
7. Smooth edges

CHM — Disadvantages (7)

1. Low accuracy
2. Slow process
3. Chemical handling risks
4. Environmental pollution
5. Masking required
6. Limited depth control
7. Not suitable for thick materials

EBM — Electron Beam Machining

EBM — Definition

EBM uses a high-velocity electron beam to remove material by melting and vaporization.

EBM — Working Principle

• Electron gun emits electrons.
• Electrons are accelerated under high voltage.
• Beam is focused on the workpiece.
• Kinetic energy converts into heat at the impact point.
• Material melts and evaporates.

EBM — Applications (7)

1. Micro drilling
2. Aerospace parts
3. Nuclear components
4. Precision machining
5. Medical devices
6. Thin sheet machining
7. Semiconductor industry

EBM — Advantages (7)

1. Very high precision
2. Micro-hole machining
3. No tool contact
4. High energy density
5. Clean process
6. Minimal distortion
7. Suitable for hard materials

EBM — Disadvantages (7)

1. High equipment cost
2. Vacuum required
3. Low MRR
4. Skilled operator needed
5. Limited work size
6. High power consumption
7. Complex maintenance

LBM — Laser Beam Machining

LBM — Definition

LBM removes material using a high-intensity laser beam focused on the work surface.

LBM — Working Principle

• Laser beam is focused by a lens.
• High temperature is generated at the focus.
• Material melts or vaporizes.
• Assist gas removes debris.

LBM — Applications (7)

1. Sheet metal cutting
2. Drilling micro holes
3. Medical surgery
4. Electronics
5. Aerospace cutting
6. Welding
7. Engraving

LBM — Advantages (7)

1. Non-contact process
2. High accuracy
3. Suitable for thin materials
4. Automation possible
5. No tool wear
6. Narrow kerf width
7. Clean operation

LBM — Disadvantages (7)

1. High initial cost
2. Limited thickness capability
3. High power requirement
4. Reflective materials are difficult
5. Heat-affected zone
6. Maintenance cost
7. Safety precautions required

USM — Ultrasonic Machining

USM — Definition

USM removes material by the abrasive action of a slurry under ultrasonic vibrations.

USM — Working Principle

• Tool vibrates at 20–40 kHz.
• Abrasive slurry flows between tool and workpiece.
• Abrasive particles hammer the surface.
• Brittle material erodes by repeated impact.

USM — Applications (7)

1. Glass machining
2. Ceramics
3. Carbides
4. Optical components
5. Semiconductor parts
6. Jewels
7. Hard brittle materials

USM — Advantages (7)

1. No heat generation
2. No tool rotation required
3. Good surface finish
4. Effective for brittle materials
5. No residual stress
6. Accurate holes possible
7. Complex shapes achievable

USM — Disadvantages (7)

1. Low material removal rate (MRR)
2. Tool wear
3. Limited to brittle materials
4. Slow process
5. Slurry handling problems
6. High cost
7. Limited depth

PAM — Plasma Arc Machining

PAM — Definition

PAM removes material by a high-temperature plasma arc (temperatures up to ~30,000 °C).

PAM — Working Principle

• Gas is ionized to form plasma.
• Plasma jet melts the material.
• High-velocity jet removes molten metal.

PAM — Applications (7)

1. Cutting stainless steel
2. Aluminum cutting
3. Shipbuilding
4. Automotive industry
5. Heavy fabrication
6. Aerospace parts
7. General metal cutting

PAM — Advantages (7)

1. High cutting speed
2. Can cut thick plates
3. High productivity
4. Automation possible
5. Low setup time
6. Versatile process
7. Relatively smooth cut

PAM — Disadvantages (7)

1. High noise levels
2. High power consumption
3. Heat-affected zone
4. Expensive equipment
5. Gas consumption
6. Less precision than some methods
7. Safety issues

Comparison: Conventional vs Non-Conventional Machining