CNC Gear Hobbing Kovar is a core capability at VT machining. We combine controlled gear cutting 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 Gear Hobbing Capability for Kovar
- Spur & helical gears
- Module range support
- Pre-grind accuracy
- High productivity
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 Gear Hobbing Kovar Works
Tooth profiles are generated in the Kovar blank by a synchronised cutter, then refined to the required accuracy class. Module, pressure angle and helix are programmed from your gear data.
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 Gear Hobbing Kovar
| Feature | Standard | Precision |
|---|---|---|
| Accuracy class | DIN 8 / AGMA 10 | DIN 6 / AGMA 12 |
| Profile deviation | 0.020 mm | 0.008 mm |
| Lead deviation | 0.020 mm | 0.008 mm |
| Pitch deviation (cumulative) | 0.040 mm | 0.015 mm |
| Runout | 0.030 mm | 0.010 mm |
| Tooth surface finish | Ra 1.6 µm | Ra 0.4 µm (ground) |
| Module range | m0.5–m8 | m1–m6 |
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.
Secondary Operations & Finishing
Most Kovar 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 Gear Hobbing Kovar
Small design adjustments often cut cost and lead time. Providing complete gear data (module, pressure angle, profile shift, quality class) lets us produce Kovar gears right the first time. If you send your model early, we will return practical DFM feedback before you commit to production.
Working with Kovar
Kovar is matched thermal expansion for glass/ceramic seals. 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 Gear Hobbing 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 Gear Hobbing Tolerances & Surface Finish
Gear features are produced to a specified DIN/AGMA accuracy class, with profile and lead controlled for quiet, durable running under load.
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.
Applications of CNC Gear Hobbing Kovar
Kovar 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 Gear Hobbing Kovar
Starting your project takes one email. Send your CAD or 2D drawing, the Kovar 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 Kovar
Three representative CNC Gear Hobbing 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.
Internal ring gear
- Material
- Kovar
- Size
- m2.5, z72, ID 190 mm
- Key callouts
- DIN 8, pitch deviation 0.03 mm
- Batch
- 150 pcs
Shaped rather than hobbed — an internal gear leaves no room for a hob to run out.
Worm and wheel set
- Material
- Kovar
- Size
- m3, single start
- Key callouts
- Backlash 0.05–0.10 mm as a matched pair
- Batch
- 120 sets
Supplied as matched sets and marked, because mixing pairs loses the backlash spec.
Splined shaft
- Material
- Kovar
- Size
- DIN 5480, 26 × 1.5
- Key callouts
- Fit class H7/g6, runout 0.02 mm
- Batch
- 800 pcs
Spline hobbed with the journals ground afterwards on the same centres.
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 Gear Hobbing 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 Gear Hobbing
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
Does CNC Gear Hobbing Kovar require dedicated tooling?
Most Kovar gear cutting work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
What gear accuracy class can you achieve on Kovar?
Gear accuracy is specified to DIN/AGMA classes appropriate to the application. Profile and lead are controlled so Kovar gears run accurately and quietly under load.
How clean are the edges produced by CNC Gear Hobbing on Kovar?
Machined Kovar edges are clean and to specification; edge-break or deburring is added when your drawing calls for it.
What material thickness or size range suits CNC Gear Hobbing Kovar?
We machine Kovar across a broad size range; share your part envelope for confirmation.