EDM (electrical discharge machining)
EDM (electrical discharge machining) is a process that removes material from a conductive workpiece by controlled electrical sparks between an electrode and the part, without mechanical cutting forces. It machines hardened steel and other hard materials and produces sharp internal corners, narrow slots and contours that milling cutters cannot reach.
Request a quoteAt a glance
Typical parts
- Punches, dies and cutting inserts
- Mould and die inserts with blind cavities
- Internal splines, keyways and gear profiles
- Narrow slots and sharp internal corners
- Parts in hardened steel or carbide
Quantities
- Small series of hard-to-cut features
Inspection
- CMM or optical measuring system
- Pin gauges for slots and bores
- Roughness if specified
Documents
- Dimensional report
- EN 10204 3.1 certificate
How EDM works
The workpiece and an electrode sit in a dielectric fluid, usually deionised water for wire EDM and oil for sinker EDM. A voltage between electrode and workpiece produces rapid sparks that melt and vaporise tiny amounts of material. The fluid flushes the particles away. Because the tool never touches the part, hardness does not matter and thin or delicate features do not deflect.
Wire EDM
uses a thin wire that travels continuously through the part along a programmed contour. Used for through-contours, punches, dies and internal profiles.
Sinker EDM
(die-sinking) uses a shaped electrode, usually graphite or copper, that is sunk into the part. Used for blind cavities and three-dimensional shapes.
EDM hole drilling
makes small, deep holes and start holes for wire EDM.
Dimensional and surface inspection
EDM contours are measured on a coordinate measuring machine (CMM) or an optical measuring system, with pin gauges for slots and bores. Surface roughness is measured with a profilometer where the drawing specifies it.
Standard documents are a dimensional report and a material certificate to EN 10204 3.1. More on the quality page.
Materials for EDM
Tool steel
- 1.2379
- 1.2842
- 1.2343
Hardened alloy steel
- 42CrMo4
- 16MnCr5 (case hardened)
Stainless steel
- 1.4301
- 1.4404
Carbide
- tungsten carbide
Copper alloys and aluminium
- on request
There is no fixed size or tolerance limit. Send us your drawing and we will define the right production route and confirm feasibility.
Is this the right process?
When EDM is the right choice
- The material is hardened and the feature cannot be ground
- The part needs sharp internal corners, narrow slots or internal profiles
- Thin or delicate features would deflect under cutting forces
When another process is better
- Unhardened material without sharp internal corners: CNC milling is faster and cheaper
- Round hardened surfaces such as bearing seats: CNC grinding
- Flat profiles from sheet or plate: laser cutting or waterjet cutting
Related pages
- CNC millingCNC milled parts in steel, stainless steel and aluminium from machine shops in Türkiye: housings, plates, brackets and machined castings, with CMM reports.
- CNC turningCNC turned parts in steel, stainless steel, aluminium and brass from machine shops in Türkiye: shafts, pins, bushings and flanges, with dimensional reports.
- Secondary operationsHeat treatment, galvanising, powder coating, KTL e-coating, painting and assembly for cast, forged and machined parts, managed by QProcess in the same order.
- CNC grindingCNC cylindrical, centreless and surface grinding of shafts, pins, spools and plates from machine shops in Türkiye, usually after hardening, with reports.
- Machinery and equipmentMachine bases, housings, shafts, gear blanks, guides and plastic wear parts for machinery and equipment manufacturers, produced by manufacturers in Türkiye.
- Other industriesCast, forged, machined and plastic parts for pumps and valves, hydraulics, rail, material handling, industrial automation, robotics and marine equipment.
- IndustriesCast, forged, machined and plastic parts for agricultural, construction, energy, vehicle, machinery, aerospace and medical manufacturers, produced in Türkiye.
Frequently asked questions
What is the difference between wire EDM and sinker EDM?
Wire EDM cuts through the part with a thin wire electrode, like a precise fret saw, and makes through-contours such as punches, dies and internal profiles. Sinker EDM sinks a shaped electrode into the part and makes blind cavities, for example mould cavities, ribs or internal splines that do not go through.
Which materials can be machined by EDM?
Any electrically conductive material: hardened and unhardened steel, stainless steel, tool steel, carbide, copper alloys, aluminium and titanium. Plastics, ceramics and other non-conductive materials cannot be machined by EDM.
Is EDM suitable for series production?
EDM is slower than milling or turning, so it is mainly used where cutting tools cannot do the job: hardened material, sharp internal corners, narrow slots. For small series of such features it is often the most economical route.
Send your drawing. You get a quotation in 3 to 5 working days.
Your drawings are handled confidentially; NDA on request.