CNC Sinker EDM Spring Steel is a core capability at VT machining. We combine controlled EDM machining with material-aware setup for Spring Steel — an alloy that is high yield strength and elastic recovery — to produce parts that meet your specification first time.
Process Data for CNC Sinker EDM Spring 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 Spring Steel (65Mn / SK5 / 1075), the most common Spring Steel grade we see for CNC Sinker EDM. Typical values for Spring Steel (65Mn / SK5 / 1075), Annealed or hardened & tempered strip; confirmed on the first part.
CNC Sinker EDM Capability for Spring Steel
- Blind cavities & ribs
- Fine surface (VDI grades)
- Tolerance to ±0.005 mm
- Hardened tool steel
Spring Steel material properties, finishing options and grade notes are on our CNC Wire EDM Spring Steel page.
How CNC Sinker EDM Spring Steel Works
Material is removed from the Spring 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.
We start from your supplied geometry and tolerance scheme. The setup is designed to minimise re-clamping, which protects positional accuracy across features. A first article is verified against the drawing before the balance of the batch is released.
Achievable Tolerances for CNC Sinker EDM Spring 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.
CNC Sinker EDM Tolerances & Surface Finish
EDM holds tolerances to roughly ±0.002–0.005 mm with no cutting force on the Spring Steel part, producing fine, controlled surface textures and sharp internal corners impossible to mill.
The tightest tolerances are reserved for the features your drawing flags as critical. Share your tolerance scheme and we will confirm what is realistic before quoting.
Design Tips for CNC Sinker EDM Spring Steel
Small design adjustments often cut cost and lead time. EDM suits sharp internal corners, thin ribs and hardened Spring 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.
Applications of CNC Sinker EDM Spring Steel
Spring Steel parts made this way are found throughout aerospace, medical, automotive, electronics and industrial equipment. Prototype, bridge and production volumes are all welcome.
Typical Spring Steel Parts for CNC Sinker EDM
Illustrative examples of CNC Sinker EDM Spring 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.
Micro slot in nozzle
- Material
- Spring 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.
Carbide punch
- Material
- Spring 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.
Spline broach section
- Material
- Spring Steel
- Size
- Ø28 × 40 mm
- Key callouts
- Involute profile ±0.005 mm, Ra 0.4 µm
- Batch
- 60 pcs
Wire EDM after hardening to 62 HRC — the profile would not survive being cut soft and heat-treated.
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 Spring 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 Spring 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 Spring Steel
Send the drawing, the Spring 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
Can you EDM-machine hardened Spring Steel?
Yes. EDM removes material by electrical discharge rather than cutting force, so hardened and difficult Spring Steel can be machined to fine detail and tight tolerance without distortion.
What surface finish is achievable on Spring Steel with CNC Sinker EDM?
Surface finish on Spring Steel is controlled to your specification; we confirm the achievable Ra against your callout.
Does CNC Sinker EDM Spring 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 Spring Steel parts to my drawing?
Yes. Spring 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.