Removing most of the billet to form the PCB pocket leaves thin, tall walls that want to spring after roughing. We staged roughing, a stress-relief pause, and light finishing passes to hold wall position.
Case study · Electronics
Aluminum Electronics Housing — 6061-T6 Instrument Enclosure
A pocketed 6061-T6 instrument enclosure with connector cutouts, standoff bosses, and conductive grounding pads, machined and finished for a low-volume electronics build.
- 6061-T6
- Black anodize
- EMI grounding
Project overview
Project overview
This project is a two-piece CNC machined aluminum electronics housing: a pocketed body that carries the PCB and internal standoffs, and a matching lid with a sealing land and captive screw pattern. It started as a single prototype for design validation and moved into low-volume production on the same routing.
The engineering challenge was less about any single feature and more about keeping everything consistent as the billet emptied out. Deep pocketing leaves thin walls that distort if you rough and finish them in one pass, so the plan separated bulk material removal from finishing and added a stress-relief pause in between. Connector cutouts, mounting features, and the lid screw pattern were machined in a single 5-axis setup so they reference each other rather than stacking setup error.
Finishing was decided with the machining plan, not after it: black anodize for the finished instrument look, with grounding pads and the lid contact ring masked and chem-film coated so the enclosure still bonds electrically for EMI. Specific dimensions, quantities, and the customer are left as placeholders — the engineering approach is representative of the electronics housings we machine.
Technical specification
Part specification
Key manufacturing parameters for this project. Values marked as placeholders stand in for confidential production data.
| Parameter | Specification |
|---|---|
| Overall envelope | Placeholder — e.g. 180 × 120 × 45 mm |
| Minimum wall thickness | 1.5 mm nominal, 1.0 mm in local ribs |
| General tolerance | ±0.05 mm (ISO 2768-f unless noted) |
| Connector / mounting positions | ±0.02 mm within a single setup |
| Sealing face flatness | 0.05 mm over 100 mm on the lid land |
| Surface finish (as-machined) | Ra 1.6 µm on cosmetic exterior faces |
Engineering challenges
What made this part difficult
The manufacturability risks we planned around before cutting metal.
Anodize is an insulator, so EMI grounding pads and the lid contact ring had to stay conductive. Those zones were masked and chem-film coated while the rest of the housing anodized black.
Connector cutouts, the lid screw pattern, and internal standoffs all reference each other. Machining the critical features in one 5-axis setup kept them aligned instead of stacking setup error.
Manufacturing process
How the part was made
The routing from raw stock to finished, inspected components.
- Step 1: Engineering review
Checked wall thickness, corner radii, and boss engagement against the drawing, and confirmed which pads needed to stay conductive before quoting. - Step 2: Roughing from billet
Bulk pocketing of the enclosure body and lid from 6061-T6 plate with stepped depths to control tool load. - Step 3: Stress relief and finishing
A relief pause between roughing and finishing, then light finishing passes on walls, floors, and sealing lands. - Step 4: 5-axis feature machining
Connector cutouts, vents, and mounting features cut across multiple faces in one setup to hold position. - Step 5: Deburr and masking
Edge-break, clean, then mask the grounding pads and lid contact ring ahead of finishing. - Step 6: Finishing and final inspection
Black anodize, chem-film on masked pads, then dimensional and cosmetic sign-off.
Inspection methods
How quality was verified
Dimensional and process controls used to sign off the part. See our full aluminum part inspection process.
Full dimensional FAI against the drawing on the first part, with a report available to the customer. Placeholder for the customer's specific AQL.
Connector positions and pocket depths verified on a CMM during the run, not just at the end.
Lid-to-body fit, screw engagement, and cosmetic faces reviewed under standard lighting before packing.
Surface finishing
Finishing and post-processing
Finishing decided alongside the machining plan. Compare options in the aluminum surface finishes hub.
Even matte black exterior for a finished instrument look and corrosion protection, applied after a light bead blast for uniformity.
Grounding pads and the lid contact ring kept electrically conductive for EMI bonding per MIL-DTL-5541.
Part number and connector labels laser marked after anodize — no inks or adhesives to wear off.
Typical application
Where this enclosure is used
Machined-from-billet enclosures like this suit electronics programs where casting tooling is not justified, but wall precision, sealing, and EMI performance still matter — instruments, controllers, and sensor electronics in the tens-to-hundreds of units per release.
Because the routing scales, the same enclosure design moves from a single prototype to recurring production without redesign.
- Manufacturability review
Every project starts with an engineering review of tolerances, wall thickness, and finish before we quote. - Prototype to production
The same routing scales from a first article to recurring production batches. - Documentation
Material certificates and first article inspection reports are available on request.
Explore the engineering
Related capabilities, materials, and pages
This project connects to our wider aluminum machining program. Start with our engineering capabilities, then dive into the specific products, materials, industries, and finishes involved.
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