Role of dielectric in Electro-Discharge Machining (EDM) In EDM, what is the primary purpose of the dielectric working fluid in the inter-electrode gap?

Introduction / Context:
Electro-Discharge Machining removes material by a series of controlled electrical discharges between a tool (electrode) and a conductive workpiece, separated by a small gap filled with a dielectric fluid such as kerosene, deionized water, or EDM oil.

Given Data / Assumptions:

• Sparking occurs when the dielectric breaks down locally.
• Debris must be carried away to sustain stable machining.
• Heat from each discharge must be dissipated.

Concept / Approach:
The dielectric serves multiple critical functions: it initially insulates the gap until the applied voltage causes breakdown, localizes and channels the discharge, cools the electrode and work, and flushes eroded particles to maintain a clean gap that prevents arcing and short circuits.

Step-by-Step Solution:
Before breakdown: dielectric insulates and controls where/when a spark can occur.At breakdown: the dielectric ionizes, allowing a short-duration plasma channel (spark) to form.After discharge: flow of dielectric cools the zone and removes debris (recast, vaporized particles).

Verification / Alternative check:
EDM instability (arcing, shorting) often traces to poor flushing or degraded dielectric; improving circulation restores stable pulsing, confirming the roles described.

Why Other Options Are Wrong:
Each listed function is valid; choosing only one ignores the multi-function nature. Therefore, “All of these” is correct.

Common Pitfalls:
Using contaminated dielectric, inadequate flushing, or incorrect viscosity—each leads to poor surface finish and tool wear.

Final Answer:
All of these