01
Bore runout after the second op
Flip the part and the bearing bore drifts. A 0.03 mm runout is enough to load the bearing on one side and shorten its life. The cause is usually a soft fixture and no datum control between operations.
Aluminum Housings · 5-Axis Milled
CNC Milling Center Aluminum for Inner Housings and Bell Housings
Sealed faces, bearing bores and bolt patterns held to ±0.005 mm on 6061, 7075 and ADC12 billet. Upload a STEP file and get a DFM review with your quote inside 12 hours.
±0.005 mm tolerance16 five-axis centersRa 0.8–1.6 μm standardOne part to 10,000+ISO 9001:2015IATF 16949:2016
±0.005 mmPositional and profile tolerance
16Simultaneous 5-axis machining centers
4,000 mmMaximum processing size
99.99%Qualification rate before shipment
Where aluminum housings go wrong
Four Problems We See in Billet Housings
Most rejected inner and bell housings fail on the same four points.
02
Sealing faces that leak
Flatness on a thin-wall flange moves after clamping pressure is released. If the face is not checked unclamped, the gasket will not hold oil. We measure flatness on the free part, not in the vise.
03
Wall thickness that wanders
A 2 mm wall on a deep pocket can deflect during roughing and spring back later. The result is a thin spot nobody sees until the housing is pressure tested or the mating shaft rubs.
04
Delays from unclear drawings
Missing datum callouts, no finish spec, or an ambiguous thread call cost days of back and forth. We flag these in the DFM report before cutting metal, so the first part is the right part.
How we machine them
One Setup Where It Counts, Datum Control Everywhere Else
The method depends on which features have to agree with each other.
Five-axis strategy
Bores, faces and bolt patterns in one setup
For an inner housing or a bell housing, the critical relationship is between the bearing bore, the mounting face and the bolt circle. If those three are cut in separate setups, every fixture error stacks into the result. On our simultaneous 5-axis centers we reach the bore, the face and the pattern without releasing the part, so the position between them comes from the machine, not from the fixture.
That matters most when the housing is long or asymmetric. A gearbox bell housing with an offset starter pocket is a good example. It cannot sit flat on a three-axis table without a dedicated tombstone. Five-axis removes that cost, and it removes the re-fixture step where most scrap is created.
- 1Ø400 mm rotary tableHandles round and semi-round housings up to that swing.
- 24,000 × 400 × 150 mm travelFor long, narrow transmission and inner housings.
- 3In-process probingDatum and bore position checked before the finish pass.
Thin-wall control
Roughing, stress relief, then finish
Aluminum moves when you remove material from one side of a billet. A housing with a 2 mm wall and deep pockets is the worst case. We rough with a deliberate allowance, let the part rest, then take the finishing cuts. On parts with tight flatness, we split roughing and finishing across shifts so the material has time to settle.
Chip evacuation is the other half of the job. Deep pockets trap chips, and a recut chip is what scratches a sealing face. Through-spindle coolant and peck-free toolpaths keep the pocket clean. For 6061 and 6082 we run high-speed toolpaths with light radial engagement; for 7075 we slow the feed and watch tool wear, because the same alloy that holds a thread well will also work-harden at the cut edge.
- 1Ra 0.2–0.8 μm availableFor sealing faces and bearing bores that need it.
- 2Deburr before inspectionNo sharp edge reaches the CMM or the customer.
- 3Full traceabilityHeat number and program revision recorded per lot.
Alloy selection
Which Aluminum for Which Housing
Pick by load path, then by finish and weldability.
| Alloy | Best for | Watch out for |
|---|---|---|
| 6061 / 6061-T6 | General inner housings, brackets, covers | Moderate strength; hard anodize can chip |
| 6082 | Structural housings with welded joints | Similar to 6061; buy consistent temper |
| 7075 | High-load bell housings, thin ribs | Lower corrosion resistance; not weldable |
| 2024 | Fatigue-loaded aerospace housings | Poor corrosion resistance bare; coat it |
| 5052 / 5083 | Formed covers, marine and damp environments | Not for high-strength machined bores |
| ADC12 (cast) | Complex thin webs where billet waste is high | Porosity risk; needs pressure-tight spec |
What we do
Services Around Aluminum Housings
One supplier from the first model to the production run.
01
5-Axis CNC Machining
Simultaneous five-axis milling for housings with angled faces, bores and pockets that would need multiple fixtures on a three-axis machine.
02
4-Axis and 3-Axis Milling
For square housings, covers and plates. Often the cheaper route when the part has one dominant axis and no compound angles.
03
CNC Turning and Mill-Turn
Round and semi-round bell housings machined in one cycle on 16 mill-turn centers, with the bore and face cut in the same chuck.
04
Rapid Prototyping
First-article housings in a few days for fit checks, flow testing and design review before tooling or a production order.
05
Surface Finishing
Anodizing, hardcoat, chromate, bead blasting and laser marking. Character height down to 1.5 mm for part numbers and traceability codes.
06
Die Casting and Vacuum Casting
When annual volume makes billet uneconomical, we move the same geometry to a casting process and machine the critical features.
Capability envelope
Equipment and Inspection Scope
Numbers for planning your part size and tolerance.
| Item | Range | Notes |
|---|---|---|
| Tolerance | ±0.005 mm (±0.0002 in) | Tighter on specific features by review |
| Finish | Ra 0.2–3.2 μm | Ra 0.8–1.6 μm is the default |
| Max part size | 4,000 mm | Long travel 4,000 × 400 × 150 mm |
| Medium envelope | 750 × 1,150 × 550 mm | Also 600 × 600 × 600 mm |
| Rotary capacity | Ø400 mm table | Round and semi-round housings |
| Machine count | 127 CNC machines | 16 five-axis, 12 four-axis, 27 three-axis |
| Inspection | 100% before shipment | Material, in-process and final checks |
| Certifications | ISO 9001, IATF 16949, ISO 13485, ISO 27001 | Reports on request |
Why GreatLight
What You Get Beyond the Machine
Six reasons engineers keep sending housings here.
15Y
Machining aluminum since 2011
Fifteen years on billet housings, brackets and enclosures. The tooling and workholding knowledge is already in the shop, not learned on your order.
12h
Quote and DFM in 12 hours
You get a price and a written manufacturability review the same working day. Production can start within 24 hours of approval.
3–5d
Parts ship in 3–5 days
Standard milled aluminum housings leave the plant in three to five days. Historical late-delivery probability sits below 2%.
150
Technicians across 3 plants
7,600 m² of manufacturing space in Dongguan plus a Singapore factory. Capacity is not rented from a third party.
0 MOQ
From one prototype to 10,000+
No minimum order quantity. A single housing for a fit check is treated with the same process sheet as a production lot.
ISO 27001
Your drawings stay yours
Secure upload, restricted access, and a signed NDA on request. Customer files are never shared or used as samples.
7,600 m²Manufacturing space
127High-precision CNC machines
99.99%Qualification rate
3Wholly-owned plants
Industry fit
Where These Housings Go
Automotive and EV bell housings
Motor-to-gearbox adapters and inner housings with a concentric bore and a flat mounting face.
- ±0.005 mm bore position
- IATF 16949:2016
- Ra 0.8–1.6 μm faces
Industrial machinery gearboxes
Housings that must keep shaft alignment across a long, narrow casting or billet body.
- 4,000 mm travel
- Bore-to-bore alignment
- 100% inspection
Electronics and control enclosures
Sealed inner housings and chassis where flatness controls gasket performance and EMI contact.
- Flatness checked unclamped
- Conductive anodize
- Laser marking 1.5 mm
Robotics and automation joints
Compact aluminum housings with angled faces and tight mounting patterns for actuator stacks.
- 5-axis one-setup
- ±0.005 mm pattern
- No MOQ
FAQs
Questions Engineers Ask Before Ordering
What tolerance can you actually hold on an aluminum housing?
Our standard working tolerance is ±0.005 mm, equivalent to ±0.0002 in. That applies to bores, positions and profiles where the drawing calls it out.
Some features need more room than that. A long thin flange or a deep pocket on 7075 will move with heat and cutting force, so we will tell you in the DFM report which callouts we can hold as drawn and which need a note.
Should I use billet or cast aluminum for my housing?
Billet is the safer choice for prototypes, low volume and any part where pressure tightness matters. There is no porosity to find during testing, and the mechanical properties are uniform.
Die casting wins when the geometry is complex, the walls are thin and the annual volume is high enough to amortize tooling. We quote both and machine the critical bores and faces either way.
How do you keep thin walls from distorting?
Three things: rough with an allowance, let the part rest, then finish. On tight parts we split roughing and finishing across shifts so the material has time to settle.
We also choose the workholding before the toolpath. Supporting a thin wall from the inside with a soft jaw or a custom fixture removes most of the chatter that causes a wandering wall thickness.
What file formats do you accept?
STEP, IGES and STL are the usual formats. Native CAD files are fine if that is easier for you.
Send the 3D model plus a 2D drawing with datums, tolerance stack-up and surface finish callouts. If there is no drawing, we work to the model and note our assumptions in the DFM review.
Is there a minimum order quantity?
No. We run one prototype or a 10,000+ part production order on the same equipment and the same process sheet.
A single housing for a fit check is quoted and scheduled like any other job. Volume pricing comes from cycle time and setup amortization, not from a floor.
How do you protect our design?
Uploads go through a secure portal with restricted access. We hold ISO 27001:2022 for information security.
A non-disclosure agreement is available on request, and we do not use customer parts as samples or show them to other clients.
Which finishes are available on aluminum housings?
Anodizing in clear, color, hardcoat and conductive types. Also electroless nickel, zinc, silver and gold plating, powder coating and black oxide.
For cosmetic or handling reasons we offer bead blasting, tumbling, brushing and polishing. Laser marking goes down to 1.5 mm character height for part numbers and traceability codes.
What happens if the first article is out of spec?
We inspect the first article against the drawing before running the lot. If a dimension is out, we correct the program or the fixture and cut a new first article.
Every part is inspected 100% before shipment, with raw material checks, in-process monitoring and a final inspection. Inspection reports are available when you need them.
Send a Drawing, Get a Quote and a DFM Report
Upload your STEP file and we will come back with pricing, a manufacturability review and a process note for your aluminum housing.
12-hour quote100% inspectionNo MOQNDA on request
