Can wire-cut EDM cut hardened steel?

Yes. Hardness makes no difference, which is why dies and punches are usually hardened first and then wire cut to final size.

How accurate is wire-cut EDM?

About ±0.005–0.01 mm is normal with finishing passes; better is possible on good machines in controlled conditions.

What is the difference between wire cut and spark EDM?

Wire cut slices through the part with a moving wire, like a precise band saw. Spark (die-sinking) EDM burns a shaped cavity into the part with an electrode, so it can make blind pockets.

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Wire-cut EDM machine

Also called: wire EDM, WEDM, wire erosion machine, wire cut machine, EDM wire cut

A wire-cut EDM machine cuts any electrically conductive metal, even fully hardened steel, with a thin brass wire that removes material by electrical sparks in water. It cuts accurate profiles, about ±0.005–0.01 mm, without force, which makes it ideal for dies, punches and precise parts.

Quick facts

Cuts: Any conductive material, including hardened steel and carbide
Wire: Usually brass, about 0.1–0.3 mm (0.25 mm is common)
Typical accuracy: About ±0.005–0.01 mm
Surface finish: About Ra 0.4–1.6 µm with finishing passes
Maximum thickness: Often 200–400 mm, depending on the machine
Taper cutting: Commonly up to about ±15–30°

How it works

The wire runs between two guides above and below the part, and the part sits in deionised water. Thousands of sparks a second between wire and part melt away tiny amounts of metal, so the wire never touches the part and there is no cutting force.

A first pass cuts the shape; one or more finishing passes (skims) improve the accuracy and finish. For a closed shape, a small start hole is drilled first (often on an EDM hole-drilling machine).

Work it does well

Punches, dies and die inserts after hardening
Precise profiles, slots and keyways
Gears and splines in small batches
Extrusion die openings
Thin or delicate parts that would bend under cutting force

Limits

Only conductive materials (not plastics or ceramics, except conductive grades)
Cuts through the part: it cannot make blind pockets (that is spark EDM)
Slower than milling for removing large amounts of material
Hardened parts can crack if internal stresses are high: stress relief and enough surrounding material help

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Related job work

Wire-cut EDM

Machines

VMC (vertical machining centre)

Materials

Questions

Can wire-cut EDM cut hardened steel?: Yes. Hardness makes no difference, which is why dies and punches are usually hardened first and then wire cut to final size.
How accurate is wire-cut EDM?: About ±0.005–0.01 mm is normal with finishing passes; better is possible on good machines in controlled conditions.
What is the difference between wire cut and spark EDM?: Wire cut slices through the part with a moving wire, like a precise band saw. Spark (die-sinking) EDM burns a shaped cavity into the part with an electrode, so it can make blind pockets.

The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 8 October 2026.