Definition
Wire EDM uses a thin, continuously traveling wire electrode to cut a through profile in a conductive workpiece, entering and exiting the material along its cutting path. Sinker EDM (die-sinking EDM) shapes a closed cavity by plunging a precisely formed electrode into the workpiece, eroding material until the cavity mirrors the electrode's shape.
Why geometry, not cost alone, usually decides between wire and sinker EDM
Wire EDM suits open, through-cut profiles; sinker EDM suits closed cavities and complex 3D shapes such as mold cavities, which is why the choice between them follows directly from whether the required geometry is an open profile or a closed cavity.
Where the distinction shows up
Implied by the geometry: a through profile in hardened material suggests wire EDM; a closed cavity or complex 3D pocket suggests sinker EDM.
Common mistakes
Assuming either EDM branch can substitute for the other; a through profile generally isn't practical with a sinker EDM electrode, and a closed cavity generally can't be reached by a wire.
Wire EDM suits open, through-cut profiles; sinker EDM suits closed cavities and complex 3D shapes such as mold cavities, which is why the choice between them follows directly from whether the required geometry is an open profile or a closed cavity.
See how Blake reviews a partFrequently asked questions
Can wire EDM produce a closed cavity?
Generally no, since the wire needs to enter and exit the material along its path, which a fully closed cavity doesn't allow.
Does sinker EDM need its own electrode for each job?
Yes, unlike wire EDM's continuously fed wire, sinker EDM requires a precisely made electrode matching the specific cavity shape.
Which is generally faster?
It depends on the specific geometry and material; neither is universally faster, since they serve different geometric needs.