Electric discharge machining (EDM) is a non-traditional manufacturing process that removes material from workpieces through controlled electrical discharges, predominantly used for machining hard or intricate materials. The process offers high precision, minimal burrs, and works without physical contact, although it has a slower material removal rate and is limited to conductive materials. Applications span industries including aerospace, automotive, medical, and electronics, with variations like wire cut EDM and micro-EDM for specialized, detailed work.

1. Thermal Type AMPs:
Electric Discharge Machining (EDM)- working Principle-equipments-
Process Parameters-Surface Finish and MRR- electrode / Tool – Power
and control CircuitsTool Wear – Dielectric – Flushing – Wire cut EDM –
Applications- Micro-EDM, Micro-WEDM.

2. Electric Discharge Machining

3. Introduction
• Definition: Electric Discharge Machining (EDM) is a non-traditional
manufacturing process that removes material from a workpiece
through a series of controlled electrical discharges.
• Purpose: EDM is primarily used to machine hard metals or materials
that are difficult to machine using conventional methods.
• Key Feature: EDM works by creating sparks between an electrode and
the workpiece, removing material in the process without physical
contact.
• Applications: Commonly used in tool and die making, aerospace,
automotive, and electronics industries.

4. Procedure
• Setup: Position the electrode and workpiece within the dielectric fluid.
• Generate Voltage: Apply voltage between the electrode and workpiece to create
an electric field.
• Sparking: As voltage increases, a spark jumps between the electrode and
workpiece, eroding the workpiece.
• Material Removal: Each spark erodes a tiny part of the workpiece, leaving a
precise shape.
• Repetition: The spark discharge process is repeated thousands of times per
second to shape the material accurately.
• Cooling and Flushing: The dielectric fluid cools the process and flushes away the
debris.

5. Advantages of EDM
• High Precision: Ideal for creating intricate shapes and complex geometries
with high accuracy.
• No Physical Contact: Reduces tool wear and is suitable for fragile or delicate
materials.
• Hard Material Machining: Easily machines hard metals, such as titanium,
Inconel, and tungsten carbide, that are challenging with traditional methods.
• Minimal Burr Formation: Produces a smooth surface finish with minimal
burrs.
• Flexibility in Shapes: Can machine complex internal shapes, sharp edges,
and intricate cavities.

6. Disadvantages of EDM
• Slow Material Removal Rate: EDM is a slower process compared to
traditional machining methods.
• High Power Consumption: Consumes significant electrical power,
making it costly for large production runs.
• Limited to Conductive Materials: Only conductive materials can be
machined, limiting its application.
• Tool Wear: Although contactless, the electrode can experience wear
over time, especially in die-sinking EDM.
• Surface Hardening: The process can create a thin heat-affected zone,
leading to surface hardening, which may require additional processing.

7. Applications
• Aerospace Industry: Creating turbine blades and precise engine parts.
• Automotive Industry: Manufacturing intricate molds and dies for
components.
• Medical Field: Producing complex, precise parts for surgical
equipment.
• Electronics: Creating fine, detailed parts for electronic devices and
connectors.

8. Power and Control Circuits
• Introduction: Power and control circuits are fundamental to the EDM
process. They regulate the discharge energy, spark frequency, and
pulse duration, ensuring precise control over the material removal
rate.
• Function: The power circuit supplies high-frequency electrical pulses,
while the control circuit adjusts these parameters based on the
material properties and desired surface finish.
• Importance: Effective control circuits enable consistent, accurate
material removal and prevent over-cutting or overheating, which can
lead to unwanted tool wear or poor surface finish.

9. Tool Wear
• Introduction: Tool wear refers to the gradual erosion of the EDM
electrode (tool) during the machining process.
• Causes: Tool wear occurs due to continuous spark discharges that
gradually erode the electrode material, particularly during long
machining sessions.
• Impact: Excessive tool wear can reduce precision, increase
operational costs, and affect the tool's lifespan, requiring frequent
adjustments or replacement to maintain accuracy.

10. Dielectric
• Introduction: In EDM, a dielectric fluid (usually deionized water or oil)
serves as an insulator and coolant, critical for stable and efficient
machining.
• Function: The dielectric fluid controls the spark gap, quenches the
spark to avoid excessive heat, and flushes away debris from the
machining area.
• Benefits: Using a dielectric fluid improves machining accuracy,
maintains electrode lifespan, and reduces the risk of short-circuiting
and overheating.

11. Flushing
• Introduction: Flushing is the process of circulating dielectric fluid
through the machining area to remove debris and maintain a stable
spark gap.
• Purpose: Effective flushing prevents debris from building up in the
gap, which could cause arcing, surface damage, or inconsistent
machining.
• Methods: There are various flushing techniques, including side
flushing, jet flushing, and through-hole flushing, each suited to
different machining situations and electrode geometries.

12. Wire Cut EDM
• Introduction: Wire Cut EDM, also known as WEDM, is a type of EDM
that uses a thin, electrically charged wire as the cutting tool.
• Process: The wire moves along a predetermined path, creating
precise cuts and intricate shapes without contacting the workpiece
directly.
• Applications: Wire Cut EDM is ideal for producing complex parts,
contours, and cavities in hard materials, making it widely used in die-
making, aerospace, and medical device manufacturing.

13. Micro-EDM
• Introduction: Micro-EDM is an advanced form of EDM designed for
creating extremely small, detailed features with high precision,
usually in the micrometer range.
• Process: Micro-EDM uses specialized, smaller electrodes to achieve
high accuracy and is suitable for machining miniature components
and fine details.
• Applications: This technology is popular in industries like
microelectronics, medical devices, and watchmaking, where fine
details and small dimensions are essential.

14. Micro-WEDM
• Introduction: Micro-WEDM is a variant of Wire EDM tailored for
micromachining applications, allowing for intricate cuts on a very
small scale.
• Process: It uses an ultra-thin wire, often below 50 microns, to achieve
extremely high precision cuts, ideal for components with complex
geometries and tight tolerances.
• Applications: Micro-WEDM is extensively used in electronics,
micromechanics, and biomedical engineering, where accuracy at
micro-level scales is crucial for component functionality.