CNC Surface Grinding Invar from VT machining delivers precision Invar parts produced to your exact drawing. Surface grinding produces flat, parallel faces with fine finish using a horizontal abrasive wheel, and we tune every parameter to the behaviour of Invar, which is ultra-low thermal expansion.
CNC Surface Grinding Capability for Invar
- Flatness within 0.003 mm
- Ra to 0.1 µm
- Parallelism control
- Hardened-steel capable
Invar Material Data
| Density | 8.11 g/cm³ |
|---|---|
| Tensile strength | 450–590 MPa |
| Yield strength (0.2%) | 275 MPa |
| Hardness | 130–160 HB |
| Melting point | 1427 °C |
| Thermal conductivity | 10.5 W/m·K |
| Thermal expansion | 1.2 (0–100 °C) ×10⁻⁶/K |
| Electrical conductivity | 2% |
| Machinability (C36000 = 100%) | 25% |
| Grades we run | Invar 36, Super Invar 32-5, Alloy 42, Alloy 46 |
Published typical values for Invar 36 (FeNi36). Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
The low expansion is the whole point, so machining stress is the enemy. Rough, stress-relieve at 315–425 °C, then finish — otherwise the part moves after it leaves the machine.
How CNC Surface Grinding Invar Works
An abrasive wheel removes a fine, controlled layer from the Invar part. Wheel specification, dressing interval, infeed and coolant are matched to the alloy's hardness so the surface is not burned or left with residual stress.
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 Surface Grinding Invar
| Feature | Standard | Precision |
|---|---|---|
| Size (OD, ID, thickness) | ±0.005 mm | ±0.002 mm |
| Flatness over 100 mm | 0.010 mm | 0.003 mm |
| Parallelism | 0.010 mm | 0.003 mm |
| Roundness | 0.005 mm | 0.002 mm |
| Squareness | 0.010 mm | 0.005 mm |
| Surface finish | Ra 0.4 µm | Ra 0.1 µm |
| Workpiece hardness | up to 62 HRC | up to 65 HRC |
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 Surface Grinding Invar
We are happy to suggest design tweaks that improve manufacturability. Allowing adequate grind stock, specifying realistic flatness over the true datum, and relieving corners help us hit tight tolerances on Invar efficiently. If you send your model early, we will return practical DFM feedback before you commit to production.
CNC Surface Grinding Tolerances & Surface Finish
Ground Invar reaches single-micron tolerances on size, flatness and parallelism, with surface finishes down to Ra 0.1–0.4 µm — and a near-mirror finish on suitable alloys.
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.
CNC Surface Grinding Quality & Inspection
We control quality throughout the process, not just at the end. In-process checks plus final inspection — including CMM where specified — keep every Invar part to print. Inspection reports, material certificates and first-article documentation can be supplied on request.
Working with Invar
As a material, Invar is ultra-low thermal expansion. Our setup reflects the alloy's machinability so the finished part is accurate and free of avoidable defects.
We verify the exact grade and condition before machining, and traceable mill certs are available on request. We can work to your nominated material source or specification when required.
Secondary Operations & Finishing
Finished Invar parts can move straight into secondary operations under one roof. Typical add-ons are deburring, passivation, anodising, plating, blasting, polishing and laser marking. We coordinate the whole chain so you receive complete, inspection-ready parts.
Applications of CNC Surface Grinding Invar
Customers order CNC Surface Grinding Invar 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.
How to Order CNC Surface Grinding Invar
Getting a quote is simple. Share your model, the material grade, your quantity and target tolerances. You receive a clear quotation with lead time and honest manufacturability feedback.
Parts We Have Run in Invar
Three representative CNC Surface Grinding Invar jobs, with the callouts that actually drove the process plan. Yours will differ — these are here so you can judge whether your part is in our range before you spend time on an RFQ.
Punch tool
- Material
- Invar
- Size
- Ø10 × 60 mm
- Key callouts
- OD ±0.002 mm, roundness 0.002 mm, Ra 0.1 µm
- Batch
- 300 pcs
Cylindrical ground after hardening to 60 HRC — machining soft would not hold the size.
Lapping plate
- Material
- Invar
- Size
- 300 × 300 × 30 mm
- Key callouts
- Flatness 0.005 mm over the full face
- Batch
- 20 pcs
Ground, stress-relieved, ground again — one pass will not hold flatness on this area.
Slitter blade
- Material
- Invar
- Size
- Ø150 × 1.5 mm
- Key callouts
- Thickness ±0.005 mm, edge concentricity 0.005 mm
- Batch
- 400 pcs
Ground in a stack so all blades in a set share the same thickness.
Finishing Options for Invar
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| 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 Surface Grinding Invar
- 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 Invar 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 Surface Grinding
Other Processes for Invar
Send the drawing, the Invar grade and the quantity. You get pricing, lead time and any DFM notes back — usually within one business day.
Request a QuoteFrequently Asked Questions
Which industries use CNC Surface Grinding Invar parts?
CNC Surface Grinding Invar parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise Invar components are required.
What tolerances can you hold for CNC Surface Grinding Invar?
Achievable tolerances for Invar grinding depend on the alloy, geometry and feature size. Grinding routinely holds single-micron tolerances on diameter, flatness and parallelism. Exact figures are confirmed against your drawing callouts.
What surface finish is achievable on Invar with CNC Surface Grinding?
Grinding can take Invar to a fine finish — typically Ra 0.1–0.4 µm, and to a mirror grade on suitable alloys.
Why is Invar a good choice for CNC Surface Grinding?
Invar is ultra-low thermal expansion, which makes it well suited to CNC Surface Grinding. We tune the process to the alloy so the finished Invar grinding part meets your dimensional and functional requirements.
What is the typical lead time and minimum order for CNC Surface Grinding Invar?
CNC Surface Grinding prototypes for Invar can be produced quickly and scaled to series production. Send your drawing and quantity and we will advise lead time and any minimum order.