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Machine Tools & Manufacturing Equipment · Category Intelligence

EDM

Electrical discharge machining removes conductive material with controlled sparks — no cutting force, so it holds tight tolerance in hardened steel and carbide and cuts shapes a tool can't reach. The pick is wire vs sinker, driven by whether you're cutting a through-profile or burning a blind cavity.

◆ Deep category · engineer-grade decision intelligence

Product types

Where engineers draw the lines within edm.

Wire EDM
A traveling wire cuts a through-profile like a bandsaw with no force. Dies, punches, gears, and tight-tolerance profiles in hardened material.
Sinker (Ram/Die-Sink) EDM
A shaped graphite/copper electrode burns its mirror image into a blind cavity. Mold cavities, ribs, and sharp internal corners.
Small-Hole / Fast-Hole Drill
A rotating tube electrode drills tiny deep holes — including EDM start holes and cooling holes in turbine blades.
Micro / Wire micro-EDM
Fine wires and electrodes for micro-features, medical, and precision tooling at sub-mm scale.

Specs that matter

The numbers to compare first — and which are hard deal-breakers.

Work tank / axis travels (X/Y/Z)
Defines the largest workpiece and cut envelope.
Deal-breaker
Max workpiece weight & height
Part plus fixture must fit and stay within rated table load and Z clearance.
Deal-breaker
Best achievable accuracy & surface finish (Ra/VDI)
Governs whether you hit die/mold tolerance and finish without polishing.
Deal-breaker
Cut speed (mm2/min) & generator technology
Drives throughput and cost per part; modern generators cut faster with less wire.
Key
Automatic wire threading (AWT) reliability
Unattended running depends on the machine re-threading after every wire break.
Key
Taper capability (wire) / C-axis (sinker)
Angled cuts for die relief; rotation for complex cavity electrodes.
Key
Dielectric type (deionized water vs oil) & filtration
Water for wire speed; oil for sinker fine finish. Filtration drives finish and stability.
Nice-to-know
Flushing pressure & adaptive control
Debris removal prevents secondary discharges, wire breaks, and DC arcing.
Nice-to-know

How engineers decide

Rules of thumb behind the common trade-offs.

Wire or sinker?
Wire for any through-profile — dies, punches, extrusion tooling. Sinker for blind cavities, sharp internal corners, and features open on only one side, like a mold rib.
When EDM instead of grinding/milling?
When the material is too hard to machine efficiently, the corner is too sharp for a cutter, there's zero tolerance for cutting force on a thin/delicate part, or the geometry is simply unreachable by a rotating tool.
How do I get a mirror finish on a sinker cavity?
Multiple orbit passes with progressively lower energy and a fine-finish generator; graphite for fast roughing, copper for the finest finishes. Expect trade-off: fine finish is slow.
Water or oil dielectric?
Deionized water on wire for speed and cleanliness. Oil on sinker where the finest finishes and lowest electrode wear matter — at the cost of fire management and filtration.
▼ From the field

What goes wrong — War Stories

Expensive failure modes engineers design around.

⚠ Wire breakage / lost unattended run
Cause: Poor flushing, too-aggressive settings, dirty dielectric
Design around it: Tune power to thickness, keep filtration/deionization in spec, ensure AWT reliability, back off in poor-flush zones.
⚠ Recast layer & micro-cracks
Cause: Heat-affected zone from spark energy, especially at high power
Design around it: Add low-energy finish/skim passes to remove recast, critical for fatigue-loaded tooling and aerospace parts.
⚠ Taper error / out-of-square cut
Cause: Wire lag and poor flushing on thick sections
Design around it: Use skim passes, correct wire tension, and adaptive power; verify squareness on a test cut.
⚠ DC arcing / cavity damage
Cause: Debris buildup causing continuous (not pulsed) discharge
Design around it: Improve flushing, use adaptive control that retracts on short-circuit, keep dielectric clean.

Key builders

Manufacturer-direct sources we anchor specs to.

SodickMakinoGF Machining Solutions (AgieCharmilles)Mitsubishi ElectricFanucONAChmerExcetek

Standards we hold specs to

ISO 230Test code for machine-tool accuracy & repeatability
VDI 3400 / ISO 25178EDM surface texture / areal surface finish references
ISO 28881Safety requirements for EDM machines
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