Stainless Steel KF Vacuum Flange Adapter with External Thread and Ra 0.4 µm Seal Face Finish by Single Setup Machining
KF Vacuum Adapter Threading
,Vacuum Seal Face Turning
,KF Flange Leak Face Fit
This KF vacuum flange adapter with an external thread is CNC turned by Dongguan Changxinda Precision Technology Co., Ltd., a machining factory established in 2008. The KF taper, the sealing face and the external thread are machined in one setup, so the seal face stays perpendicular to the thread axis and the cone stays concentric with the bore. The sealing face is finished to Ra 0.4 µm with form held to ± 0.01 mm, and can be helium leak tested on request.
On a vacuum joint the leak path is almost always the seal face, not the thread. A face that is slightly convex, scratched or torn by a turning insert will not let the O-ring or centring ring seat, and the joint shows a slow rise in pressure that is hard to trace. We finish the seal face with light, single-direction passes and polish without smearing, then check flatness and roughness before the part is packed for cleanroom use.
ISO 9001:2015 • 304 / 316L stainless steel • Helium leak test on request • NDA available • Exporting since 2008
Each vacuum adapter follows a controlled eight-stage route:
- Drawing review & DFM: STEP / IGES / SolidWorks / 2D PDF checked for KF size, taper angle, thread spec and seal face geometry.
- Material: 304 or 316L stainless steel with mill certificates and heat-number traceability.
- Programming: CAM toolpaths sequenced so the seal face is cut last, after the thread and bore are complete.
- Turning body & bore: outside diameter and through bore machined to size, concentricity established.
- Cutting the KF taper: the 15° flange cone machined to vacuum sealing geometry and checked with a KF gauge.
- Threading: external thread cut on the same axis, verified with a thread ring gauge.
- Seal face finish: face machined flat and polished to Ra 0.4 µm, with no tool marks across the O-ring path.
- Cleaning & inspection: degreased, passivated or electropolished, then CMM and roughness checked; helium leak test available.
The KF adapter is a starting point. We machine custom vacuum fittings with your own flange size, taper, thread standard, bore, length and material — all to drawing.
We sign an NDA before engineering review, restrict drawings to the assigned programming and machining team, and never display or reuse customer geometry. Fixtures and programs built for your part stay dedicated to your program, and surplus or reject parts are scrapped on request.
Changxinda runs a plant established in 2008 with 90+ staff, CNC lathes and 4-axis / 5-axis machining centers backed by a dedicated QC lab.
One shop, ten industries, one inspection standard:
Phone / tablet / laptop housings, heat sinks, camera brackets, VR/AR headset structural parts, smart wearable shells.
Automation fixtures, jigs, module frames, transmission sliders, motor mounts, sensor housings, assembly line components.
Vacuum chambers, vacuum fittings, precision bases for semiconductor equipment, thermal and insulating parts, inspection tooling.
Surgical instrument bases, medical testing instrument housings, endoscope accessories, medical aesthetic device structural parts (medical-grade aluminum / stainless steel).
New-energy motor housings, battery end plates, sensor brackets, headlamp structural parts, modified parts, hydraulic valve blocks.
Aircraft structural parts, drone frames, landing gear accessories, aviation instrument housings (lightweight precision parts).
Optical lens barrels, lens mounts and bases, light source heat sinks, camera module brackets, inspection optical platforms.
5G heat dissipation cavities, filter parts, signal adapter structural parts, communication equipment housings.
Robotic arm joint parts, robot bases, reducer housings, AGV structural parts.
Testing equipment housings, precision gauge bases, flow meter parts, laboratory equipment accessories.
- KF flange taper and external thread machined in one setup
- Seal face flat and polished to Ra 0.4 µm
- Form held to ±0.01 mm on taper, thread and face
- 304 / 316L stainless steel with heat-number traceability
- Passivation or electropolishing for low outgassing
- Thread checked with ring gauge, taper with KF gauge
- Helium leak test available on request
- Clean, degreased packing for vacuum service
- NDA and IP protection on request
- From 1-piece prototypes to scheduled production
| Product Type | Stainless steel KF vacuum flange adapter with external thread |
|---|---|
| Machining | CNC turning, single setup |
| Tolerance | ±0.01 mm on critical features |
| Material | 304 / 316L stainless steel |
| Seal Face Finish | Ra 0.4 µm, ground and polished |
| Flange | KF 16 / 25 / 40 / 50, 15° taper |
| Surface Treatment | Passivation / electropolishing |
| Testing | CMM, roughness, helium leak test on request |
| MOQ | 1 piece |
The O-ring or centring ring seals against that face. Tool marks, scratches or a slightly convex face create a leak path that shows up as slow pressure rise, so we finish it to Ra 0.4 µm and check flatness.
Taper, thread and seal face are machined in one setup from one datum, so the face stays perpendicular to the thread axis and the cone stays concentric.
Yes — 304 and 316L are both standard, with mill certificates and heat-number traceability. Other grades are available on request.
Helium leak testing can be arranged on request and reported with the batch, alongside CMM and surface roughness records.
Yes, before engineering review. Drawings are limited to the assigned programming and machining team and never reused or displayed.
Prototypes 3–7 days, small batches 7–14 days, mass production 14–30 days depending on complexity, with rush support available.
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