CNC EDM Drilling 321 Stainless Steel is part of VT machining's grade-specific capability. 321 Stainless Steel is corrosion resistant, strong and hygienic, and we combine controlled EDM machining with material-aware setup to produce parts that meet your specification.
CNC EDM Drilling Capability for 321 Stainless Steel
- Austenitic/martensitic grades
- Corrosion resistant
- Tolerance to ±0.01 mm
- Typical hardness 70–200 HB (annealed)
321 Stainless Steel Material Data
| Density | 8.00 g/cm³ |
|---|---|
| Tensile strength | 515 MPa |
| Yield strength (0.2%) | 205 MPa |
| Hardness | 170 HB |
| Melting point | 1400–1450 °C |
| Thermal conductivity | 16.2 W/m·K |
| Thermal expansion | 17.3 ×10⁻⁶/K |
| Electrical conductivity | 2.4% |
| Machinability (C36000 = 100%) | 45% |
| Grades we run | 303, 304/304L, 316/316L, 321, 410, 416, 420, 17-4PH, 2205 duplex |
Published typical values for 304. Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
It work-hardens the moment a tool dwells. Constant feed and positive-rake tooling; a rubbing pass leaves a glazed skin the next tool cannot get through.
Machining 321 Stainless Steel with CNC EDM Drilling
When EDM machining 321 Stainless Steel, machinability is moderate; work-hardens, so positive-rake tooling and steady feeds are used to avoid glazing. Our process plan reflects this so the finished part holds its tolerances without distortion or poor finish.
Documented parameters for 321 Stainless Steel mean predictable cycle times and stable, repeatable results.
Achievable Tolerances for CNC EDM Drilling 321 Stainless 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 EDM Drilling Quality & Inspection
Quality is built in, not inspected on. We monitor key features during the run and confirm them at final inspection, with CMM verification available for tight tolerances. We provide the inspection and traceability records your quality system requires.
CNC EDM Drilling Tolerances & Surface Finish
EDM holds tolerances to roughly ±0.002–0.005 mm with no cutting force on the 321 Stainless 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.
Design Tips for CNC EDM Drilling 321 Stainless Steel
Small design adjustments often cut cost and lead time. EDM suits sharp internal corners, thin ribs and hardened 321 Stainless 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.
Secondary Operations & Finishing
Most 321 Stainless Steel parts need some finishing, which we manage in-house or through vetted partners. Options include deburring and edge-breaking, heat treatment, surface grinding, polishing, and plating or anodising for corrosion resistance and appearance. Give us the finished-part requirement and we will sequence every operation correctly.
Why 321 Stainless Steel?
Customers select 321 Stainless Steel for CNC EDM Drilling because it is corrosion resistant, strong and hygienic. We handle grade verification and any required heat treatment or finishing.
Applications of CNC EDM Drilling 321 Stainless Steel
321 Stainless Steel parts made this way are found throughout aerospace, medical, automotive, electronics and industrial equipment. Prototype, bridge and production volumes are all welcome.
How to Order CNC EDM Drilling 321 Stainless Steel
Starting your project takes one email. Send your CAD or 2D drawing, the 321 Stainless Steel grade and condition, the quantity and any finish or inspection requirements. We respond quickly with price, lead time and any DFM notes, in clear English.
Finishing Options for 321 Stainless Steel
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| Citric passivation | — | ASTM A967 / AMS 2700, removes free iron |
| Electropolish | 5–25 µm removed | Ra improves by roughly half, hygienic surface |
| Brushed / grained | Ra 0.4–1.6 µm | No. 4 finish, directional |
| PVD coating | 2–5 µm | TiN, TiCN for wear surfaces |
| Deburr / edge break | 0.05–0.3 mm | All parts unless the drawing says otherwise |
| Bead blast | Ra 1.6–3.2 µm | Uniform matt finish, hides tool marks |
| Laser marking | — | Part number, lot code, data matrix |
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 EDM Drilling 321 Stainless 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 321 Stainless 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.
321 Stainless Steel in Other Processes
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Send the drawing, the 321 Stainless Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
What is the typical lead time and minimum order for CNC EDM Drilling 321 Stainless Steel?
CNC EDM Drilling prototypes for 321 Stainless Steel can be produced quickly and scaled to series production. Send your drawing and quantity and we will advise lead time and any minimum order.
What surface finish is achievable on 321 Stainless Steel with CNC EDM Drilling?
Surface finish on 321 Stainless Steel is controlled to your specification; we confirm the achievable Ra against your callout.
Why is 321 Stainless Steel a good choice for CNC EDM Drilling?
321 Stainless Steel is corrosion resistant, strong and hygienic, which makes it well suited to CNC EDM Drilling. We tune the process to the alloy so the finished 321 Stainless Steel EDM machining part meets your dimensional and functional requirements.
What tolerances can you hold for CNC EDM Drilling 321 Stainless Steel?
Achievable tolerances for 321 Stainless 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.