Kovar Machining Services
Precision parts in Fe-Ni-Co alloy 4J29 / ASTM F15 — the standard material for glass-to-metal seals and thermally matched packaging.
Hermetic-package experience
ZEISS CMM report with every order
Prototype in 5–7 working days
What we make from Kovar
Kovar’s expansion curve matches borosilicate glass and ceramic substrates, which is why it dominates sealed packaging. We machine it into:
- Hermetic housings & packages — relay cans, sensor headers, connector shells for glass-to-metal sealing
- RF & microwave components — package bases, lids, tuners where CTE match protects solder joints through thermal cycling
- Photonics bases & carriers — optical submounts and butterfly-package hardware
- Power tube & vacuum device hardware — anodes, grids supports, feedthrough components (civil applications)
- Hybrid Invar/Kovar assemblies — machined and assembled with controlled fit
Kovar machining: what changes vs. stainless
A common buyer question: “Is Kovar just like stainless steel to machine?” No — three differences matter:
Gummier chips, built-up edges
Kovar’s austenitic structure work-hardens and produces tough, stringy chips. Sharp positive-rake carbide tooling and proper coolant pressure prevent built-up edge and glazing.
Thermal cycle discipline
The whole point of Kovar is its expansion match. Parts that will be brazed or glass-sealed must not carry machining stress into the seal — we stress-relieve before finish machining.
Plating readiness
Most Kovar parts are nickel or gold plated before sealing. We finish surfaces and break edges with plating thickness in mind, so your plater isn’t compensating for our mistakes.
Specifications & capabilities
| Parameter | Capability |
|---|---|
| Material designations | Kovar / 4J29 / ASTM F15 / UNS K94610 / 1.3981 |
| Precision tolerance | ±0.02 mm standard · ±0.002 mm capability |
| Surface finish | Ra 0.8 µm standard; Ra 0.4 µm on sealing surfaces on request |
| Processes | CNC milling & turning, wire EDM, stamping-blank machining, grinding |
| Heat treatment | Stress-relief and hydrogen-anneal coordination with certified partners |
| Inspection | ZEISS CMM, FAI dimensional report against GD&T with every shipment |
| MOQ | None — prototypes welcome |
Need Kovar parts that seal right the first time?
Send the drawing — we reply within one business hour.