VT machining provides CNC Cylindrical Grinding Invar for customers who need accurate, repeatable Invar components. Because Invar is ultra-low thermal expansion, we adapt the process to suit — controlling the variables that matter for this alloy.
CNC Cylindrical Grinding Capability for Invar
- Roundness within 0.002 mm
- OD tolerance ±0.002 mm
- Ra to 0.2 µm
- Between-centers work
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 Cylindrical 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.
Every job begins from your CAD model or 2D drawing. Fixturing and tool paths are planned so the most critical dimensions are produced in the most rigid, repeatable setup. Critical dimensions are checked on the first part and monitored through the run.
Achievable Tolerances for CNC Cylindrical 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 Cylindrical Grinding Invar
A few design choices make a real difference to cost and quality. 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.
Secondary Operations & Finishing
We complete Invar components with the secondary steps your drawing calls for. We arrange heat treatment, surface treatment, marking and assembly as needed. Tell us the final spec and we will plan the full route so parts arrive ready to use.
Working with Invar
Invar offers a useful combination of properties: it is ultra-low thermal expansion. Those characteristics shape how we approach grinding — from tool and parameter selection to work-holding and coolant.
If your application is sensitive to alloy condition, we agree the specification in writing and document it. Stock is sourced from reputable suppliers so what you order is what you receive.
CNC Cylindrical Grinding Quality & Inspection
Consistent quality comes from disciplined process control. Critical dimensions on Invar parts are checked in-process and verified at final inspection using calibrated instruments and, where required, CMM measurement. Full documentation — dimensional reports, mill certs, FAIR — is available when your programme needs it.
CNC Cylindrical 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.
Final tolerances are governed by the material's behaviour, wall thickness and overall stiffness. We give honest DFM feedback if a callout would be costly or better achieved another way.
Applications of CNC Cylindrical Grinding Invar
CNC Cylindrical Grinding of Invar supports parts across aerospace, medical, automotive, electronics, semiconductor, energy and general industrial sectors. We scale from one-off prototypes to ongoing production while holding the same quality.
How to Order CNC Cylindrical Grinding Invar
Ordering Invar parts is straightforward. Provide the drawing, material, quantity and any certification needs. Our engineers reply — in English — with feasibility, pricing and a realistic lead time, usually within one business day.
Parts We Have Run in Invar
Three representative CNC Cylindrical 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 Cylindrical 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 Cylindrical 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
What is the typical lead time and minimum order for CNC Cylindrical Grinding Invar?
CNC Cylindrical 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.
What is CNC Cylindrical Grinding Invar and how is it done?
CNC Cylindrical Grinding Invar refers to cylindrical grinding finishes outer diameters of rotational parts to precise size and roundness. Applied to Invar — ultra-low thermal expansion — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.
Does CNC Cylindrical Grinding Invar require dedicated tooling?
Most Invar grinding work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
Can VT machining make custom Invar parts to my drawing?
Yes. Invar Invar grinding 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 surface finish is achievable on Invar with CNC Cylindrical Grinding?
Grinding can take Invar to a fine finish — typically Ra 0.1–0.4 µm, and to a mirror grade on suitable alloys.
What material thickness or size range suits CNC Cylindrical Grinding Invar?
We machine Invar across a broad size range; share your part envelope for confirmation.