CNC Punching Kovar is a core capability at VT machining. We combine controlled punching with material-aware setup for Kovar — an alloy that is matched thermal expansion for glass/ceramic seals — to produce parts that meet your specification first time.
CNC Punching Capability for Kovar
- Sheet thickness 0.5–6 mm
- Hole position repeatability ±0.10 mm
- Punch/die clearance set per material
- Louver, emboss and tap-extrude tooling
Kovar Material Data
| Density | 8.36 g/cm³ |
|---|---|
| Tensile strength | 517 MPa |
| Yield strength (0.2%) | 340 MPa |
| Hardness | 140–160 HV |
| Melting point | 1450 °C |
| Thermal conductivity | 17.3 W/m·K |
| Thermal expansion | 5.1 (30–200 °C) ×10⁻⁶/K |
| Electrical conductivity | 3.5% |
| Machinability (C36000 = 100%) | 35% |
| Grades we run | Kovar / ASTM F15, Alloy 42, Alloy 52 |
Published typical values for Kovar (ASTM F15). Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
Sealing surfaces must stay clean. Parts destined for glass-to-metal seals are degreased and handled without bare hands after final machining.
How CNC Punching Kovar Works
A CNC turret presses hardened punches through the Kovar sheet into matching dies. Punch-to-die clearance is set as a percentage of thickness so the cut edge stays clean and burr is minimal.
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 Punching Kovar
| Feature | Standard | Precision |
|---|---|---|
| Hole position across sheet | ±0.15 mm | ±0.10 mm |
| Hole diameter | ±0.10 mm | ±0.05 mm |
| Overall blank size | ±0.20 mm | ±0.10 mm |
| Minimum hole | 1.0 × thickness | 0.8 × thickness |
| Hole-to-edge distance | 2.0 × thickness | 1.5 × thickness |
| Burr height | 0.08 mm | 0.03 mm (deburred) |
| Sheet thickness range | 0.5–6.0 mm | 0.5–3.0 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 Punching Tolerances & Surface Finish
Punched Kovar holds hole-position repeatability around ±0.10 mm across the sheet, with consistent hole quality when punch/die clearance is matched to the gauge.
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 Punching 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 Kovar part to print. Inspection reports, material certificates and first-article documentation can be supplied on request.
Secondary Operations & Finishing
Finished Kovar 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.
Working with Kovar
As a material, Kovar is matched thermal expansion for glass/ceramic seals. 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.
Design Tips for CNC Punching Kovar
We are happy to suggest design tweaks that improve manufacturability. Keeping hole-to-edge and hole-to-hole distances at least 1.5–2× thickness avoids distortion and tearing in punched Kovar. If you send your model early, we will return practical DFM feedback before you commit to production.
Applications of CNC Punching Kovar
Customers order CNC Punching Kovar 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 Punching Kovar
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 Kovar
Three representative CNC Punching Kovar 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.
Louvred cover
- Material
- Kovar
- Size
- 350 × 200 × 1.2 mm
- Key callouts
- Louvre height 4 ±0.3 mm
- Batch
- 2,000 pcs
Louvre tooling forms and cuts in one hit; the direction is set by the airflow spec.
Shim washer
- Material
- Kovar
- Size
- Ø20 / Ø10 × 0.5 mm
- Key callouts
- ID/OD ±0.05 mm, burr < 0.03 mm
- Batch
- 25,000 pcs
Clearance set at 6% of thickness per side to keep the burr under spec without deburring.
Contact blank
- Material
- Kovar
- Size
- 18 × 9 × 0.3 mm
- Key callouts
- Contour ±0.05 mm, burr-free on the contact face
- Batch
- 50,000 pcs
Punched with the burr deliberately on the non-contact side.
Finishing Options for Kovar
| 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 Punching Kovar
- 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 Kovar 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 Punching
Other Processes for Kovar
Send the drawing, the Kovar 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 material thickness or size range suits CNC Punching Kovar?
Punching suits Kovar sheet roughly 0.5–6 mm thick, with clearance matched to the gauge.
How clean are the edges produced by CNC Punching on Kovar?
Punched Kovar edges are clean when punch/die clearance is correct; we set clearance to the gauge and can add deburring if specified.
What tolerances can you hold for CNC Punching Kovar?
Achievable tolerances for Kovar punching depend on the alloy, geometry and feature size. Punching holds hole-position repeatability to around ±0.10 mm. Exact figures are confirmed against your drawing callouts.
What surface finish is achievable on Kovar with CNC Punching?
Surface finish on Kovar is controlled to your specification; we confirm the achievable Ra against your callout.
Does CNC Punching Kovar require dedicated tooling?
Punching uses programmable turret tooling; standard tools cover most patterns, with special tools added for unique forms.