EDM capabilities
EDM: material removed by electrical discharge | Conductive materials | Internal corner radius depends on wire/electrode and discharge gap.
- Wire EDMSodick AQ537L at 500 × 370 × 310 mm, plus a DK7750 moly wire machine at 630 × 500 × 400 mm
- Die-sinkSodick AG40L at 400 × 300 × 300 mm for cavities a cutter cannot reach
- ToleranceUp to ±0.003 mm, confirmed per profile and machining conditions.
- Material hardnessHardened tool steel 58–62 HRC.
- CornersRadius depends on wire diameter and discharge gap.
- Thin wallMachined by electrical discharge, no mechanical cutting force.
- MaterialConductive materials | Standard EDM does not apply to plastics, ceramics, glass.
- QualityISO 9001:2015, certified by URS under UKAS accreditation
Reference route: mill soft stock → heat treatment → wire cut/grind to finish | Route and cost confirmed per part.
EDM machine list
Equipment: wire EDM, die-sink EDM, fiber laser welding | Laser welding is a separate process.
| Make / Model | Type | Work envelope X × Y × Z (mm) | Origin |
|---|---|---|---|
| SODICK AG40L | Die-sink EDM | 400 × 300 × 300 | Japan |
| SODICK AQ537L | Wire-cut EDM | 500 × 370 × 310 | Japan |
| DK7750 Moly Wire | Wire-cut EDM | 630 × 500 × 400 | China |
| MJ-300W Fiber Laser | Laser welding | Ø 200 × 250 | China |
Table values: machine travel | Usable part size depends on clamping and wire guides.
Typical EDM applications
- PunchesSKD11 punches and dies | Wire cut after heat treatment.
- Mould partsMould inserts, slides and guide blocks with sharp internal corners
- KeywaysInternal keyways, splines and square holes that a drill or cutter cannot produce
- SlotsNarrow slots, thin webs, fragile parts.
- ProfilesProfile blocks and gauges held to ±0.003 mm on the finished form
- Broken tool removalRemoval of broken taps or bolts by die-sink EDM | Assessed by location and accessibility.
- Laser weldMJ-300W fiber laser welding for fine repair and small joints, in the same section
Internal corners: radius to be specified on the drawing | EDM or milling route assessed from geometry | Design changes require approval.
EDM process requirements
Use EDM for hardened material and inaccessible features
EDM is used for hardened material, sharp internal corners and features a milling cutter cannot reach. Milling is used where it's practical.
Conductive materials
EDM applies to electrically conductive materials such as steel, stainless steel, aluminium and copper alloys.
Recast-layer removal
EDM leaves a thin recast layer. Where fatigue life or die performance matters, the drawing should specify stoning or polishing after EDM.
Roughing before EDM
Remove bulk material by milling before heat treatment, then use EDM for the final hardened features.
Wire EDM work envelope
Maximum wire EDM travel is 630 × 500 × 400 mm. The usable part size depends on clamping clearance.
Taper and section thickness
Taper angle, section thickness and required accuracy are reviewed together because wire deflection increases on steep tapers.
Common EDM materials
- Tool steelSKD11 and D2 at 58–62 HRC, cut after hardening. SKD11 notes →
- Hot workSKD61 and H13 die components, usually 44–52 HRC after tempering
- Alloy steel4140 and SCM440, hardened after roughing. 4140 notes →
- Stainless17-4PH after ageing, and 304 and 316L where a sharp corner is needed. 17-4PH notes →
- CarbideTungsten carbide inserts and wear parts, cut slowly with the right wire and settings
- Not forPlastics, ceramics, quartz and glass. The process needs a conductive workpiece
Tool steel: grade and chemical composition checked against the material certificate | D2/SKD11/1.2379 not substituted with Cr12MoV. Why that matters →
Measured before it ships
- CMMMitutoyo CRYSTA-APEX V in a climate-controlled lab, checked against a calibrated reference standard
- OpticalHexagon Optiv Lite for fine profiles and corners a probe cannot reach
- Material hardnessMitutoyo QMH 14BX. Every hardened batch is checked and the reading goes on the report
- ReportDimensional report in both inch and millimetre, with profile features reported against the model
- SurfaceRecast removed by stoning or polishing where the drawing calls for it, and recorded on the report
- PackingOiled, VCI wrapped, foam partitioned. Ground and EDM faces protected one by one
Functional surfaces and tolerances after heat treatment: specified on the drawing | EDM/grinding sequence follows the final-dimension requirements.
Common questions
Wire EDM tolerance?
Wire-cut profile tolerance: up to ±0.003 mm | Confirmed per material, thickness and geometry.
Wire cutting hardened steel?
Material: hardened tool steel 58–62 HRC | Route: mill soft stock → heat treatment → wire cut to finish.
Wire EDM size limits?
Machine travel: DK7750 630 × 500 × 400 mm; Sodick AQ537L 500 × 370 × 310 mm | Usable part size depends on clamping.
Can you EDM plastic or ceramic?
EDM requires a conductive workpiece | Plastics, ceramics, quartz, glass: other processes assessed.
Do I need to worry about the recast layer?
Surface after EDM: recast layer present | Stoning/polishing removal per drawing requirement.
Why is EDM more expensive than milling?
EDM cost follows machining time | Features that can be milled: milling route assessed | Radius changes require design approval.
Can you remove a broken tap from our part?
Broken taps removed by die-sink EDM | Assessment data: photo and drawing | Feasibility confirmed per part.
Related information
Grinding
Okamoto and Chevalier surface and NC grinding after heat treatment, ±0.005 mm.
SKD11 / D2 tool steel
Most of our EDM work is cut from this grade, and it's the one most often swapped for something else.
CNC milling
Rough milling before heat treatment; EDM finishing after heat treatment.