About This Part
A vacuum chamber body is the pressure vessel that holds an evacuated volume. In semiconductor vacuum parts machining, these chambers house wafer stages, process gases, optical columns or electron beams — and a defect in a wall, a port intersection or a sealing face is not visible until the chamber fails to pump down to base pressure or shows a virtual leak that persists for weeks of troubleshooting. Unlike bolted-together fabrications, a billet-machined chamber body eliminates welds that would otherwise be leak sites, but it introduces a different set of machining challenges around deep cavities, consistent wall thickness and stress management in a part where 80% of the starting billet may be removed as chips. This cnc vacuum chamber body is machined from **Aluminum 6061**, selected for its low outgassing rate after proper cleaning, weldability for any secondary ports or flanges, and good machinability for heavy material removal. The part is produced by **5-axis CNC milling + turning**, combining turned port features with milled chamber geometry. All sealing faces, port bores and critical wall dimensions are held to **±0.005 mm on critical dimensions**. For vacuum equipment machining in UHV ranges, wall consistency and absence of trapped volumes matter as much as surface finish — a thick or thin wall spot changes how the chamber deflects under vacuum, and a hidden internal pocket pumps forever.
**Part:** Vacuum Chamber Body
**Process:** 5-axis CNC milling + turning
**Material:** Aluminum 6061
**Tolerance:** ±0.005 mm on critical dimensions
**Inspection:** 100% CMM verification, full report with shipment
Challenges of This Part & How We Machined It
Deep-cavity wall thickness consistency
Machining a chamber body from a solid billet means removing a high percentage of the raw stock — in many cases 80% or more of the starting weight comes out as chips. The cavity walls are designed to be thin for weight savings but consistent in thickness to avoid vacuum-induced deflection (under atmospheric load, a wall that is 1 mm thinner than its neighbor deflects more and can cause seal misalignment). When milling a deep cavity with a long-reach end mill, tool deflection and chatter can leave walls uneven or tapered, and the error is invisible from the outside. We use a layered roughing strategy with progressively shorter tools as we reach deeper (reducing overhang and deflection at each stage), take constant-engagement finish passes at controlled stick-out, and verify wall thickness with ultrasonic thickness gauging at multiple points before the part leaves the machine.
Port intersections and virtual-leak prevention
Where ports meet the main chamber volume, or where cross-drilled passages intersect inside a wall, a blind corner creates a trapped volume that pumps only slowly through a tiny clearance — a virtual leak that mimics a real leak during pump-down and is notoriously difficult to locate. Burrs at these intersections make the problem worse, and a sliver of partially-severed metal can vibrate and create intermittent leaks. We program port intersections to create clean, visible breaks rather than leaving thin slivers of material, deburr every internal intersection with dedicated tools, and verify visible intersections with a borescope. The chamber pumps down to design pressure without mystery leaks.
Sealing-face flatness across a large opening
The door or flange that seals a chamber opening bolts to a machined face with an O-ring or metal gasket. That face has to be flat around the full perimeter, and any local bump or hollow is a leak path. After deep-cavity roughing, the remaining stock has released a substantial amount of internal stress, and the part can twist slightly before finish machining — a problem that is compounded when the chamber has been flipped multiple times. We schedule the sealing-face finish pass as the last operation on the critical face, take a light spring cut to account for any post-roughing movement, and verify flatness around the full perimeter on the CMM.
Machining Sequence
1. **CAM programming with material-removal simulation** — toolpaths for deep cavity milling are simulated to ensure constant cutter engagement and avoid tool collision with the walls as the tool reaches depth.
2. **Pre-stress roughing** — bulk stock is removed in symmetric layers from the billet, with the part flipped to balance stress release before finish work begins.
3. **Stress-relief dwell** — the rough-machined body rests between roughing and finishing to allow stress redistribution before final cuts are taken.
4. **5-axis finish milling of cavity and exterior** — chamber walls, port interfaces, exterior surfaces and mounting features are finish-milled; wall thickness is checked by ultrasonic gauging during machining.
5. **CNC turning of port bores and sealing features** — circular port seats, flange registers and sealing surfaces are turned on a lathe or with 5-axis circular interpolation for concentricity.
6. **CMM inspection and leak checking** — all sealing faces, port positions and wall dimensions are verified; where specified, a helium leak check can be performed before shipment.
What You Get With Every Order
- **Free DFM review before quoting** — we flag manufacturability risk early, not after parts are made - **First Article Inspection report** with the first batch - **CMM dimensional report** on critical features - **Material certificates** for aerospace and medical grades - **Direct communication with the shop** — no trading company in between, we make the parts ourselves
Have a Drawing?
Send us your drawing or STEP file and we will come back with pricing within 48 hours. Prototype quantities and production runs both welcome — no minimum order quantity.
**TruPart Precision** trupartprecision.com | sales@trupartprecision.com WhatsApp: +86 137 1278 3205 No.114 Xinhua Road, Xinhe Dev Zone, Wanjiang, Dongguan, China