About This Part
The base plate of a vacuum system is the structural foundation that every chamber, pump and instrument bolts onto. In semiconductor equipment machining, this plate does more than hold weight — it provides sealing surfaces, locates precision motion stages, routes cooling lines, and must remain dimensionally stable through bake-out cycles and years of UHV service. A base plate that moves, warps or leaks compromises every component mounted to it, and diagnosing a leaky base in an assembled system is one of the more expensive service calls a fab can make. This cnc equipment base plate is machined from a solid billet of **Aluminum 6061**, chosen for its low outgassing characteristics after proper cleaning, good thermal conductivity for cooled stages, and machinability for complex pocketed geometry. All critical features — sealing grooves, mounting faces, locating holes and cooling-line connections — are held to **±0.005 mm on critical dimensions**. For buyers sourcing a UHV base plate cnc machined to tight geometric tolerances, the difference between an acceptable base and an excellent one is flatness stability over time and absence of virtual-leak paths.
**Part:** Vacuum Equipment Base
**Process:** 5-axis CNC milling
**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
Gasket-seal flatness across a large area
A vacuum base plate typically spans hundreds of millimeters, and the entire O-ring or metal-gasket groove must sit on a flat plane. Even 0.01 mm of local bow at a gasket groove creates a leak path that is nearly impossible to diagnose once the chamber is assembled and pumped down. Compounding this, the act of bolting a chamber to the base can pull a slightly bowed plate flat enough to seal initially — only to leak when thermal cycling during bake-out shifts the loading. We finish the sealing face and groove in light spring passes after the bulk of the pocketing is done, so that cutting forces do not introduce deflection mid-pass. The plate comes off the machine with the sealing face flat enough to hold vacuum without relying on bolt force to straighten it.
Burr-free tapped holes in vacuum service
Every tapped blind hole in a UHV component is a potential virtual leak: a burr or a chip trapped at the bottom of a hole slowly releases gas under vacuum. Worse, a loose chip that migrates into the chamber can destroy a wafer or contaminate an optical surface. We use controlled-depth tapping with spiral-flute taps designed for blind holes, run dedicated deburring tools for thread roots, and clear every hole with high-pressure coolant. After machining, parts go through a solvent and ultrasonic cleaning step to remove residual coolant and particulate before being sealed in clean packaging.
Stress relief and post-machining stability
Removing large volumes of material from one side of a thick 6061 billet releases internal stress that pulls the plate out of flat days or weeks after machining. A base that passes CMM on a Friday can be 0.05 mm out of spec by the time it reaches the assembly line — a problem that becomes visible only after the plate is bolted to a surface plate at the customer site. We symmetrically rough both sides before finish machining, schedule stress-relief time between operations (or specify stress-relieved stock for tighter-tolerance plates), and take light final passes after the part has stabilized. The plate stays flat after shipping, not just before.
Machining Sequence
1. **CAM programming with fixture planning** — symmetric roughing strategy is programmed first, ensuring stock is removed evenly from both sides to minimize stress-induced warp.
2. **Bilateral rough milling** — the billet is flipped and roughed from both faces to equalize stress, with uniform finishing stock left on all critical surfaces.
3. **Stress-relief dwell** — parts rest between roughing and finishing to allow stress redistribution before final cuts.
4. **5-axis finish milling** — sealing grooves, mounting faces, locating bores and pockets are finished in a controlled sequence, starting with non-critical pockets and ending with the gasket face.
5. **Deburring and cleaning** — all tapped holes and cross-holes are deburred under magnification; parts are ultrasonically cleaned to remove coolant residue and particulate before packaging.
6. **CMM inspection** — flatness of gasket faces, groove dimensions, hole positions and overall geometry are verified on the CMM; dimensional report and material certificates included.
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