How does EDM compare to traditional machining in material removal rate?

Material Removal Mechanisms

Traditional machining relies on mechanical cutting forces, whereas Electrical Discharge Machining (EDM) removes material through controlled electrical discharges that melt and vaporize the surface. As a result, EDM can process extremely hard superalloys—such as Stellite 6B and high-strength Inconel grades—without tool wear or excessive cutting forces.

However, EDM generally has a **slower material removal rate (MRR)** compared to traditional CNC milling or turning. While conventional machining may achieve tens of cubic centimeters per minute, EDM typically operates at a lower rate due to its pulsed erosion process.

Comparison of Removal Rates

For superalloys that are difficult to cut—such as single-crystal or heat-resistant alloys—traditional machining tools face rapid wear, cooling limitations and poor chip evacuation. EDM offers superior controllability but with reduced MRR. High-speed milling may outperform EDM in volume removal, but EDM excels where geometric precision and tool access are difficult or where thermal loads must be minimized.

To combine benefits, EDM is often followed by precision superalloy CNC machining to refine tolerances and surface finish.

Application-Driven Selection

In aerospace and power generation sectors, EDM is chosen for complex shapes, thin walls and deep slots that conventional tools cannot access efficiently. For high-volume removal tasks, traditional machining remains preferable. EDM’s lower MRR is compensated by its ability to process hardened materials without mechanical deformation.

Ultimately, material removal rate must be balanced with structural integrity, accuracy and thermal stability. EDM is slower—but often indispensable—when machining critical superalloy components to exacting specifications.