CNC Sinker EDM Steel from VT machining delivers precision Steel parts produced to your exact drawing. Sinker (die-sink) EDM burns a shaped electrode into metal to form precise cavities and blind features, and we tune every parameter to the behaviour of Steel, which is strong, economical, widely available carbon/alloy grades.
Process Data for CNC Sinker EDM Steel
| Electrode | Graphite (roughing) / copper (fine finish) |
|---|---|
| Relative removal rate | High (vs tool steel = medium) |
| Best finish | VDI 12-18 (Ra 0.4-0.8 µm) |
Shown for 1018 Steel, the most common Steel grade we see for CNC Sinker EDM. Typical values for 1018 Steel, Cold-drawn; confirmed on the first part.
CNC Sinker EDM Capability for Steel
- Blind cavities & ribs
- Fine surface (VDI grades)
- Tolerance to ±0.005 mm
- Hardened tool steel
Steel material properties, finishing options and grade notes are on our CNC Wire EDM Steel page.
How CNC Sinker EDM Steel Works
Material is removed from the Steel workpiece by controlled electrical discharges across a dielectric gap, with no mechanical contact. Flushing, on/off pulse timing and electrode/wire feed are set to balance speed against surface finish.
Programming is driven directly by your 3D model or print. Work-holding, tool selection and the cutting strategy are planned around the critical features and the material before the first chip is cut. First-off inspection confirms the process is centred before production continues.
Achievable Tolerances for CNC Sinker EDM Steel
| Feature | Standard | Precision |
|---|---|---|
| Profile dimension | ±0.010 mm | ±0.002 mm |
| Internal corner radius | 0.15 mm | 0.05 mm |
| Taper control over 50 mm | 0.02 mm | 0.005 mm |
| Surface finish (skim passes) | Ra 0.8 µm | Ra 0.2 µm |
| Recast layer | 10 µm | 2 µm (fine skim) |
| Start-hole diameter | 1.0 mm | 0.25 mm |
| Workpiece hardness | no limit (conductive) | no limit (conductive) |
Standard is what a normal quotation assumes. Precision is available on nominated features and is priced separately, because it needs extra setups, in-process gauging and CMM verification. Call out only the features that need it — blanket-tightening a drawing is the single most common reason a quote comes back expensive.
Design Tips for CNC Sinker EDM Steel
We are happy to suggest design tweaks that improve manufacturability. EDM suits sharp internal corners, thin ribs and hardened Steel that cannot be milled; allowing a small corner radius where possible speeds the cut. If you send your model early, we will return practical DFM feedback before you commit to production.
CNC Sinker EDM Tolerances & Surface Finish
EDM holds tolerances to roughly ±0.002–0.005 mm with no cutting force on the Steel part, producing fine, controlled surface textures and sharp internal corners impossible to mill.
Exact achievable figures depend on the alloy, the feature size and the part geometry. Tell us which dimensions are critical and we will advise feasibility up front.
Applications of CNC Sinker EDM Steel
Customers order CNC Sinker EDM Steel components for everything from instrumentation to structural and functional assemblies. Whether you need a single prototype or recurring production volume, the same process discipline applies.
Typical Steel Parts for CNC Sinker EDM
Illustrative examples of CNC Sinker EDM Steel parts and the callouts that usually drive the process plan. They show the kind of work that fits this process; they are not specific customer orders.
Carbide punch
- Material
- Steel
- Size
- Ø6 × 45 mm
- Key callouts
- OD ±0.003 mm, sharp form retained
- Batch
- 250 pcs
Carbide is EDM or grind only; there is no milling route.
Micro slot in nozzle
- Material
- Steel
- Size
- 0.15 mm wide × 6 mm deep
- Key callouts
- Width ±0.003 mm
- Batch
- 400 pcs
Cut with 0.1 mm wire; the start hole is EDM-drilled at Ø0.3 mm.
Turbine blade fir-tree root
- Material
- Steel
- Size
- 40 × 25 mm section
- Key callouts
- Profile ±0.008 mm
- Batch
- 120 pcs
Held on a dedicated fixture so every blade in the set indexes identically.
No drawing yet? Build one in the browser.
Set the metal, dimensions and features, watch the 3D model update as you type, then switch to the 2D sheet to add dimensions and tolerances. Download it or send it straight to us with your RFQ.
What We Need to Quote CNC Sinker EDM Steel
- GeometrySTEP or IGES for the 3D model, plus a PDF drawing if you have tolerance callouts. A dimensioned sketch is enough to start.
- MaterialThe exact Steel grade and condition — temper, heat-treat state or hardness. If you are not sure, tell us the function and we will suggest one.
- QuantityPrototype count and the expected annual volume. Both change how the part is made and therefore what it costs.
- TolerancesWhich features are critical. Everything else runs to our standard tolerance, which is what keeps the price sensible.
- FinishSurface treatment, cosmetic requirements, and any faces that must be masked.
- DocumentsWhether you need a material certificate, dimensional report, FAIR or PPAP with the shipment.
Missing something from the list is not a problem — send what you have. We will come back with the specific questions rather than a generic form.
Other Metals for CNC Sinker EDM
Other Processes for Steel
Send the drawing, the Steel grade and the quantity. You get pricing, lead time and any DFM notes back — usually within one business day.
Request a QuoteFrequently Asked Questions
Does CNC Sinker EDM Steel require dedicated tooling?
Wire EDM needs no shaped tooling; sinker EDM uses a shaped electrode we produce in-house for your cavity.
Can VT machining make custom Steel parts to my drawing?
Yes. Steel EDM machining is made to order from your CAD/2D drawing. Share your geometry, material grade, tolerance and quantity and we will confirm feasibility, lead time and pricing.
What tolerances can you hold for CNC Sinker EDM Steel?
Achievable tolerances for Steel EDM machining depend on the alloy, geometry and feature size. EDM holds tolerances to around ±0.002 mm with no cutting force on the part. Exact figures are confirmed against your drawing callouts.
What is CNC Sinker EDM Steel and how is it done?
CNC Sinker EDM Steel refers to sinker (die-sink) EDM burns a shaped electrode into metal to form precise cavities and blind features. Applied to Steel — strong, economical, widely available carbon/alloy grades — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.
Can you EDM-machine hardened Steel?
Yes. EDM removes material by electrical discharge rather than cutting force, so hardened and difficult Steel can be machined to fine detail and tight tolerance without distortion.