Wire EDM Capabilities and Typical Limits
These are typical limits of the process on common machines. They are not a promise for every part. We confirm tolerance and finish after we read your drawing.
Typical limits
| Item | Typical value |
|---|---|
| Materials | Any metal that conducts electricity: tool steel in the hardened state, stainless steel, carbide, titanium, nickel alloys, copper, brass, aluminum |
| Wire diameter | 0.10 to 0.30 mm. 0.20 and 0.25 mm are the most common. |
| Kerf width | Wire diameter plus the spark gap on both sides. About 0.30 to 0.35 mm with 0.25 mm wire. |
| Smallest inside corner radius | About 0.15 mm with 0.25 mm wire. About 0.07 mm with 0.10 mm wire. |
| Profile tolerance | ±0.01 mm typical. ±0.005 mm with skim passes. Tighter on review of the drawing. |
| Surface finish | Ra 2.5 to 3.2 µm after one cut. Ra 0.8 to 1.6 µm after two or three passes. Ra 0.4 to 0.6 µm after four or more. |
| Workpiece thickness | Up to about 200 to 300 mm on common machines |
| Taper cutting | Up to about ±15° on common machines, less on thick parts |
| Start holes | Every closed internal profile needs one. Drilled before heat treatment or burned by small-hole EDM afterward. |
Typical values for common machines. Not a guarantee for every part.
Inside corners and the wire
The wire is round, so every inside corner has a radius. That radius is about half the wire diameter plus the spark gap. With 0.25 mm wire it is about 0.15 mm. If your drawing shows a sharp inside corner, either accept that radius, allow a relief, or ask for finer wire and expect a slower, dearer cut. Outside corners can be sharp.
Passes, finish and tolerance
The first cut removes the material and leaves the roughest surface. Each skim pass after it takes a few hundredths of a millimeter, straightens the wall and improves the finish. Ask for the finish and tolerance the function needs. Asking for four passes where one would do adds machine time along the whole profile for nothing.
Recast layer
Wire EDM leaves a thin recast layer on the cut surface. Skim passes reduce it. If your specification limits recast, for example on aerospace or medical parts, state the limit on the RFQ so we plan the passes or a finishing step for it.
What wire EDM cannot do
- Blind pockets and cavities. The wire must pass through the part. That is sinker EDM work.
- Ceramics, plastics, glass and other materials that do not conduct electricity.
- Very thick or very large blocks beyond machine travel. Send the size and we check.
Parts we take
Stamping punches and dies
Punch, die and stripper cut to matching clearances from hardened tool steel or carbide.
Mold inserts and cores
Hardened inserts with sharp internal corners and thin ribs.
Extrusion dies
Profile openings in hot-work steel.
Internal gears, splines and keyways
Internal forms that a cutter cannot reach.
Titanium and nickel alloy profiles
Medical and aerospace shapes cut without force or heat distortion from the tool.
Carbide wear parts
Blades, guides and nozzles cut from sintered carbide.
Fixture and gauge plates
Accurate pockets and slots in ground plate.
Thin-wall and delicate parts
Features that would bend or chatter under a cutter.