CNC Bending Invar from VT machining delivers precision Invar parts produced to your exact drawing. CNC bending forms sheet metal to precise angles using a programmed press brake and back-gauge, and we tune every parameter to the behaviour of Invar, which is ultra-low thermal expansion.
CNC Bending Capability for Invar
- Angle accuracy ±0.5°
- Back-gauge positioning
- Bend allowance control
- Multi-bend sequencing
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 Bending Invar Works
The Invar blank is bent or formed against tooling under CNC-controlled ram travel and back-gauge positioning. Bend allowance and springback are compensated in the program so finished angles hit the print.
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 Bending Invar
| Feature | Standard | Precision |
|---|---|---|
| Bend angle | ±1.0° | ±0.5° |
| Flange length | ±0.30 mm | ±0.15 mm |
| Hole-to-bend distance | ±0.30 mm | ±0.15 mm |
| Minimum inside radius | 1.0 × thickness | 0.8 × thickness |
| Minimum flange height | 4 × thickness + radius | 3 × thickness + radius |
| Bend-to-bend spacing | ±0.30 mm | ±0.15 mm |
| Sheet thickness range | 0.5–8.0 mm | 0.5–4.0 mm |
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 Bending Tolerances & Surface Finish
Formed Invar holds bend angles to about ±0.5° and consistent flange dimensions, with bend allowance compensated for the material and thickness.
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.
Secondary Operations & Finishing
Most Invar 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.
Design Tips for CNC Bending Invar
Small design adjustments often cut cost and lead time. Consistent bend radii, adequate flange lengths and grain-direction awareness reduce cracking and springback in formed Invar. If you send your model early, we will return practical DFM feedback before you commit to production.
Working with Invar
Invar is ultra-low thermal expansion. We translate those properties into a process plan: the right tooling, speeds, feeds and fixturing for the alloy.
Where the grade, temper or heat-treat condition matters to performance, we confirm it with you and can supply material certificates. Material is procured to recognised standards for consistent, repeatable results.
CNC Bending 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.
Applications of CNC Bending Invar
Invar 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 Bending Invar
Starting your project takes one email. Send your CAD or 2D drawing, the Invar 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.
Parts We Have Run in Invar
Three representative CNC Bending 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.
Sheet-metal enclosure
- Material
- Invar
- Size
- 300 × 200 × 120 mm
- Key callouts
- Bend angle ±0.5°, diagonal ±0.5 mm
- Batch
- 400 pcs
Bend sequence chosen so no flange collides with the tool on the last hit.
Chassis with countersinks
- Material
- Invar
- Size
- 450 × 300 × 2 mm
- Key callouts
- Countersink depth ±0.1 mm, 6 bends
- Batch
- 700 pcs
Countersinks formed before bending while the sheet is still flat and supported.
Radiused cover
- Material
- Invar
- Size
- R150 × 500 mm
- Key callouts
- Radius ±1 mm, no tool marks
- Batch
- 200 pcs
Bumped in 14 small steps rather than rolled, because the batch does not justify a roll set.
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 Bending 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 Bending
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
Can VT machining make custom Invar parts to my drawing?
Yes. Invar Invar forming 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 material thickness or size range suits CNC Bending Invar?
We form Invar sheet and plate to your developed flat pattern and bend sequence.
What surface finish is achievable on Invar with CNC Bending?
Surface finish on Invar is controlled to your specification; we confirm the achievable Ra against your callout.
What is the typical lead time and minimum order for CNC Bending Invar?
CNC Bending 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.