EDM machining only works on electrically conductive materials—but within that group, there’s a wide range of metals and alloys that EDM handles better than traditional tools.
Here’s what you’ll find on this page:
- What types of metal work best with EDM
- How EDM compares to CNC when parts are hardened or heat-sensitive
- Materials that can’t be machined with EDM (and why)
- Examples of where EDM fits into the manufacturing process
From hardened steels to exotic alloys, here you will find a breakdown of materials we regularly cut for maximum precision CNC machining. Contact us online or call 573-646-3996 learn more about our EDM machining services at Roberson Machine Company.
What Materials Can EDM Cut?
EDM—short for electric discharge machining, or “spark machining”—lets manufacturers cut complex shapes into metal alloys without using mechanical force.
Because of how the process works, EDM is ideal for hardened steel, copper, carbide, Inconel, and other materials that are difficult to machine using conventional tools.
See below for some of the most common materials we cut using wire EDM and sinker (die sink) EDM at Roberson Machine Company.
Titanium
- Strong, lightweight, and corrosion-resistant—commonly used in aerospace and medical machining
- Difficult to cut with traditional tools due to heat sensitivity
- EDM shapes titanium cleanly without introducing thermal stress or deflection
Nickel Alloys (e.g. Inconel)
- Found in jet engines, turbines, and other high-temperature applications
- Exceptionally tough on cutting tools—abrasive and heat-resistant
- EDM handles Inconel with no tool wear and consistent dimensional control
Tool Steels (D2, A2, H13, etc.)
- Used in molds, dies, and wear parts that require durability and edge retention
- Materials that are difficult to mill or turn
- EDM cuts complex features in hardened steel without softening or re-tempering
Tungsten and Carbides
- Incredibly hard and brittle—used in nozzles, punches, and high-wear tooling
- Traditional machining can cause cracking or premature tool wear
- EDM is one of the only effective methods for shaping or finishing carbide
Stainless Steels
- Common in aerospace, food-safe equipment, and medical components
- EDM cuts cleanly across stainless steel grades including 303, 304, 316, 17-4PH, 420, and others
- Ideal for thin features and internal details that require a clean, burr-free finish
When to Choose EDM Over Traditional Machining
EDM isn’t a one-size-fits-all solution—but when your design includes tight internal features, delicate geometry, or hardened metals, it might be the only reliable option. It’s often used when CNC milling can’t reach a feature without deflection, or when heat treatment comes before final machining.
EDM is also a go-to tool during prototyping, especially when you’re testing challenging materials or pushing design limits. If surface finish, edge definition, or zero tool pressure are priorities, EDM machining is hard to ignore.
Materials That Can’t Be Machined With EDM
Because EDM relies on electrical conductivity, it won’t work on non-metallic materials. Ceramics, composites, plastics, and other non-conductive substances can’t be machined this way—they simply don’t carry an electrical charge strong enough to sustain the discharge process.
Even with metals, certain materials can cause problems. Parts with specialized coatings, surface treatments, or inconsistent conductivity (like some aluminum alloys or lead-based materials) may not cut cleanly or predictably. If you’re working with a hybrid material, layered structure, or treated surface, reach out—we can confirm whether EDM is the right approach or if another process makes more sense.
Need EDM Machining for Your Next Project? Call Roberson Machine
If you’re dealing with a tough metal—whether it’s fully hardened, heat-sensitive, or just not responding well to traditional machining—EDM may be the answer. Our team regularly works with these materials that make the most sense for the job at hand.
Send us your part specs or give us a call at 573-646-3996, and we’ll help you figure out if EDM machining is the right fit for your project.
