Sinker EDM: the route, the tolerances it holds, materials and design tips, with an indicative cost. One of 56 processes in the free finder.
Non-traditionalFamily
+/-0.01mmTypical tol.
5Route steps
24Parts in finder
Sinker EDM erodes conductive metal with electrical sparks between a shaped electrode and the part in a dielectric fluid, with no cutting force.
At a glance
When to use it, and when not
Best for
Hardened steel, fine detail, sharp internal corners and deep cavities, as in moulds and dies.
Watch for
Slow, conductive materials only, and electrode cost and wear.
Step by step
The typical route
Raw material to finished part. Steps vary with material, volume and tolerance; this is the free route from the finder.
Electrode
Machine the graphite/copper electrode.
Tooling CNC Tolerance - Lead -
Sink burn
Sink the electrode into the hardened part by spark erosion.
Tooling Sinker EDM Tolerance - Lead -
Finish
Flush and finish-burn for the final surface.
Tooling - Tolerance - Lead -
Clean
Clean the cavity.
Tooling - Tolerance - Lead -
Inspect
Check cavity and finish.
Tooling - Tolerance - Lead -
Precision
Tolerances it can hold
TYPICAL TOLERANCE IT CAN HOLD
Where this process typically lands. Tighter is possible with extra operations like grinding, at higher cost.
Materials
Materials it suits
Grade
Why it suits this
Tool steels (hardened)
EDM after hardening
Carbide
Very hard
Design
Design tips
A few general pointers for Sinker EDM. The full, part-specific DFM list is in the dossier.
EDM for features millable normally.Mill where possible.
Zero-radius internal corners.Allow a small radius.
Cost
What it costs
Sinker EDM for sharp internal corners, deep cavities, hardened material; slow, so priced by burn hours.
PER-PART COST vs VOLUME
Per-part cost drops as volume spreads tooling and setup over more parts. The exact figures for your part at your volume, in your currency, are in the dossier.
MODEL EST.
$120 to 205per part at 1 off
A rough ballpark only. The dossier gives should-cost at your exact volume and currency, with the full breakdown.
GET THE FULL DOSSIER
Everything you need to quote and source it
The free route above is yours. To actually put a number on this process and buy it well:
Should-cost at your exact volume in 12 currencies, with the material, processing, tooling and overhead breakdown
Who to source from, typical MOQ and lead time, and the exact RFQ checklist to send
A quote checker that tells you if a supplier quote is fair, and the red flags to watch
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Sinker EDM erodes conductive metal with electrical sparks between a shaped electrode and the part in a dielectric fluid, with no cutting force. The typical route is: Electrode; Sink burn; Finish; Clean; Inspect. Hardened steel, fine detail, sharp internal corners and deep cavities, as in moulds and dies.
What does Sinker EDM cost per part?
It depends on size, tolerance and volume. As a rough ballpark it starts around $120 to 205 per part at low volume and falls with quantity. The dossier gives should-cost at your exact volume and currency. Model estimates, not quotes.
What tolerance can Sinker EDM hold?
Typically about +/-0.01 mm, tighter with extra finishing operations at higher cost.
What materials suit Sinker EDM?
Common choices are Tool steels (hardened) (EDM after hardening); Carbide (Very hard).
See the exact route and should-cost for your part
The free finder maps your part to its process and full route. Pro adds should-cost at your volume, sourcing and an RFQ draft.
