Get quotes for custom EDM parts
Spark erosion removes conductive metal with no cutting force, so it cuts hardened tool steel, carbide, and exotic alloys and holds fine, intricate detail milling cannot. Upload your drawing and we'll source competitive quotes from qualified manufacturing partners.
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How OpenSpindle works
We tap our partner network. You get the best-match quote.
Upload your part and we tap our network of partner shops to get you a competitive, all-in quote that is the best match for the job.
One upload
A CAD file or a sketch. That is the whole ask on your end.
Your best-match quote
Sourced from the partner shops set up for your exact part.
All-in, on your timeline
Machining, finishing, and shipping detailed to your turnaround.
Conductive metals our EDM shops cut
EDM works on any electrically conductive metal regardless of hardness. Common alloys are below; if yours is not here, ask when you request a quote.
Specs
Tolerances you can expect
| Feature | With a drawing | No drawing supplied |
|---|---|---|
| Wire EDM profile | ±0.0002 in | ISO 2768 Fine |
| True position | ±0.0005 in | ISO 2768 Fine |
| Sinker cavity depth | ±0.001 in | ISO 2768 Medium |
| Surface finish | 8-32 Ra | 32 Ra as-cut |
Wire EDM is one of the most precise cutting processes; profiles commonly hold ±0.0002 in. Finer finishes need extra skim passes that add time. Call out the critical dimension and shops confirm before cutting.
Design rules
How to design for EDM Machining
EDM removes metal with electrical sparks, so there is no tool pressure and it can cut hardened, conductive materials.
| Design rule | Typical spec | Why |
|---|---|---|
| Min internal corner radius | = wire radius (~0.004 in) | Wire EDM leaves a small radius equal to the wire diameter. |
| Start hole (wire EDM) | required for internal cutouts | The wire must thread through a drilled start hole. |
| Material | must be electrically conductive | EDM cannot cut plastics or ceramics. |
| Sharp internal corners | near-sharp achievable | EDM reaches internal corners milling cannot. |
| Tolerances | to +/- 0.0002 in | No tool pressure means delicate, tall features survive. |
Typical starting points; a shop confirms against your part and material.
Reference
Related reference charts
Free spec + tolerance charts for designing these parts.
Secondary operations
Inserts, hardware and finishing
Threads and inserts
Tapped holes, dowel pins, and pressed inserts are added as secondary ops. EDM itself makes the precise bore, slot, or keyway; a mill or grinder handles conventional features.
Finishing
Applied after cutting. As-cut ships fastest; passivation and plating are common on EDM steel and stainless parts, and the recast layer can be polished or stress-relieved where needed.
| Finish | Materials | Adds | Can be applied with |
|---|---|---|---|
| As-cut | All | +0 days | Anything |
| Recast layer removal | Tool steel, carbide | +1-2 days | Polish |
| Passivation | Stainless only | +2 days | Bead blast |
| Zinc / nickel plating | Steel | +3-5 days | Passivation not needed |
EDM leaves a thin recast (white) layer. For fatigue-critical or mold parts, ask for it to be polished or ground off so the shop plans that pass.
Process comparison
EDM vs other processes
When another process fits better than EDM.
| Process | Best for | Typical volume | Choose it over EDM Machining when |
|---|---|---|---|
| CNC Machining | Softer materials, general geometry | Prototype to production | The material is soft enough to machine and corners are not sharp. |
| 5-Axis Machining | Contoured 3D surfaces | Prototype to production | You need contoured surfaces rather than sharp internal detail. |
Get a better quote
Getting a quote that comes back fast
| Instead of | Send this |
|---|---|
| "EDM part, need a quote" | "D2 tool steel, hardened 60 HRC, wire EDM profile per drawing, qty 25" |
| "Sharp corners inside" | "0.006 in internal corner radius, wire EDM, ±0.0005 on the slot width" |
| "Small hole in a hard part" | "⌀0.020 in hole, 0.75 in deep, small-hole EDM through carbide" |
Say the material hardness, the tightest feature, and its tolerance. Hardness is why EDM was chosen and it sets the price.
Applications
Industries we serve
EDM shops on OpenSpindle cut dies, molds, hardened tooling, and precision components for demanding industries, including AS9100 and ITAR-registered shops.
More on OpenSpindle
Need a different process?
Get a quote for these capabilities too.
Designing for this process
What actually changes your quote
Not a definition of EDM. The design choices that move your price and lead time.
Internal corner radius sets the wire
A wire EDM corner is only as sharp as the wire radius, commonly 0.004 in and up. Call out a realistic internal radius; asking for a true sharp corner forces a slower, finer wire.
Thickness drives cut time
Wire EDM cuts the full stack height in one pass, so a taller part takes proportionally longer. Cutting a stack of thin parts at once is cheaper than one at a time.
Skim passes buy finish, not shape
Each extra skim pass tightens tolerance and smooths the surface but adds time. Only spec a fine finish where the part needs it.
Give a start hole on closed profiles
A closed internal cutout needs a threading hole for the wire. Adding a small pre-drilled hole, or letting the shop pop one, avoids a surprise op on hardened stock.
Questions
Frequently asked questions
Wire EDM feeds a thin electrically charged wire through the part to cut a 2D or tapered profile through the full thickness, ideal for tight internal corners, thin webs, and precise slots. Sinker (ram) EDM burns a shaped electrode down into the part to make a blind cavity, sharp internal corner, or keyway. Many shops offer both and pick from your drawing.
Get EDM quotes
Upload a drawing and we'll source quotes from qualified manufacturing partners.
STEP · STL · IGES · DWG · DXF · PDF · and more
Uploads are secure & confidential