01
Porosity opens up at final bore
Shrinkage sits just under the skin. It survives the first two operations, then appears when you bore the bearing seat. The part is scrapped after most of the cycle time is already spent.
Drivetrain Components
Developing Precision Machined Castings
We take drivetrain castings from pattern and alloy choice through machining and inspection. One supplier for the casting, the datums, and the finished bore geometry.
Sand casting and investment castingMachined to ±0.005 mmIATF 16949:201612-hour DFM analysisNo minimum order quantity
2011Developing castings since
127High-precision CNC machines
±0.005 mmAchievable machining tolerance
99.99%Qualification rate
Failure Modes We See
Where drivetrain castings go wrong
Most of these show up after the casting is already in the fixture.
02
Datum shift between casting and print
The foundry tool sets its own datum. The machine shop picks another. Wall thickness varies around the bore and the cover no longer seals at the specified clamp load.
03
Drawings that stop at the as-cast surface
No machining stock allowance, no datum callouts, no flatness limit on the sealing face. Every shop quotes a different process and nobody can compare the numbers.
04
Supply split between two vendors
Casting from one source, machining from another. When a bore runs out of tolerance, each side blames the other and the investigation stalls for weeks.
How We Develop The Part
Casting process, datum strategy, machining sequence
Three decisions carry the whole program.
Process Selection
Sand casting or investment casting, chosen by geometry
Investment casting gives thin walls and fine as-cast detail, and tooling costs more. Sand casting absorbs heavier sections and larger housings at lower tooling cost, with more stock on the machined faces. We look at wall thickness, draft, core complexity, and how much material the machining operations must remove before we recommend either route.
A drivetrain housing with deep internal ribs and a 4 mm wall usually belongs in investment casting. A heavier cover or a large clutch housing with generous walls is cheaper in sand. When a program moves from one process to the other, we re-check stock allowance on every machined face before releasing the pattern.
- 1Wall and draft reviewFeeds, risers, and draft angles checked against the as-cast drawing.
- 2Stock allowanceMachining stock stated per face, not as a blanket number.
- 3Alloy matchADC12, A356, 6061, or ductile iron selected by load case.
Datum Strategy
Pick the datums before the fixture is built
We set the machining datums from the functional features, not from whatever the casting happens to offer. A bearing bore, a sealing face, and two mounting holes usually define the part. Those become the primary, secondary, and tertiary datums, and the first operation establishes them in one setup so the rest of the process inherits a single reference.
Then we check what the casting can actually hold. If the as-cast wall varies more than the total tolerance stack, no fixture will save the part. In that case we adjust the pattern or add a locating pad in the casting. That conversation happens at the DFM stage, before tooling is cut.
- 1One reference, one setupPrimary datums machined together to remove stack-up.
- 2Fixture from the castingLocating pads designed into the as-cast geometry.
- 3Stack-up checkWall variation compared against the total tolerance band.
Selection Guide
Which casting route fits the part
Use the geometry, not the price list, to decide.
| Feature | Sand casting | Investment casting |
|---|---|---|
| Typical wall thickness | 4–20 mm | 1.5–6 mm |
| As-cast surface | Ra 6.3–12.5 μm | Ra 3.2–6.3 μm |
| Tooling cost | Lower | Higher |
| Best for | Large housings, covers | Thin-wall, detailed parts |
| Machining stock | More, planned per face | Less, tighter as-cast |
What We Do
Services around the casting
One supplier from pattern to finished, inspected part.
01
5 Axis CNC Machining
Simultaneous 5-axis work on angled bores, ports, and contoured housings. 16 centers available.
02
CNC Milling & Turning
Mill-turn centers handle bearing seats and shaft features in fewer setups, which keeps concentricity in the machine.
03
Metal Die Casting
For higher volumes, we move a validated design to die casting with ADC12 or A380 and machine from there.
04
Rapid Prototyping
Pattern-less prototypes for fit checks before committing to foundry tooling.
05
Part Surface Finishing
Anodizing, plating, powder coating, and bead blasting on machined faces and masked areas.
06
Vacuum Casting
Small-batch urethane parts for test rigs and pre-production builds.
Capability Range
Equipment and tolerances on the floor
| Item | Specification |
|---|---|
| Machines | 127 high-precision CNC machines |
| 5-axis centers | 16 simultaneous |
| 4-axis mills | 12 |
| Mill-turn centers | 16 |
| Maximum part size | 4,000 mm |
| Tolerance | ±0.005 mm (±0.0002 in) |
| Surface finish | Ra 0.2–3.2 μm by operation |
| Inspection | 100% before shipment |
Why GreatLight
Numbers we can stand behind
Fifteen years of machining, and the process data to match.
15Y
Casting and machining under one roof
Pattern review, casting follow-up, machining, and inspection run through the same quality system, so nobody hands off a problem.
±0.005
Tolerance held on functional bores
Bearing seats, sealing faces, and mounting holes machined to ±0.005 mm where the drawing calls for it.
99.99%
Qualification rate
Verified by 100% inspection before shipment, with raw material, in-process, and final checks recorded.
12H
Quotation and DFM analysis
We return a quote with a manufacturability review within 12 hours of receiving drawings and a model.
24H
Production start
Once the design and stock are confirmed, the first operation can start within 24 hours.
0
Minimum order quantity
One prototype or a 10,000+ part run, priced and scheduled the same way.
7,600 m²Manufacturing space
150Technicians
3Wholly-owned plants
4,000 mmMaximum processing size
What Drivetrain Work Requires
Requirements we build the process around
Transmission housings
Wall thickness control around a bore that must stay concentric to the input shaft axis.
- ±0.005 mm bore
- 100% inspection
Bearing caps and covers
Flatness on the sealing face and hole pattern position held after coating.
- Ra 0.8–1.6 μm
- Leak-tight face
Clutch and gearbox parts
Ductile iron and aluminium blanks machined on mill-turn centers to keep features in one setup.
- IATF 16949:2016
- 3–5 day shipping
EV drive unit castings
Motor housings and end plates with cooling passages and machined mounting interfaces.
- 5-axis
- 99.99% qualification
FAQs
Questions engineers ask before releasing a casting
Can you machine a casting the foundry already made?
Yes, if we can inspect the as-cast geometry first. Send the casting drawing, the machined drawing, and a few sample parts or a scan.
We check wall variation and stock allowance per machined face. If the casting cannot support the tolerance stack, we say so before quoting, rather than after the first article fails.
How do you decide between sand and investment casting?
Wall thickness, draft, core complexity, and the number of machined faces drive the choice. Investment casting suits thin walls and fine as-cast detail; sand casting absorbs heavier sections at lower tooling cost.
Volumes matter less than people expect. A 500-piece run can still justify investment casting when the geometry needs it.
What tolerance can you hold on a machined bore?
±0.005 mm (±0.0002 in) on functional bores where the drawing requires it. Achievable values depend on the bore depth, the alloy, and how stable the casting is after stress relief.
For sealing faces we work in the Ra 0.8–1.6 μm range. Finer finishes down to Ra 0.2 μm are available where the application needs them.
Do you handle stress relief or heat treatment?
Casting stress relief and heat treatment are scheduled before final machining when the drawing calls for it. Machining a casting before it stabilizes is a common cause of bore distortion.
If your print specifies a heat treat condition, tell us at the DFM stage. That changes the machining sequence, not just the material callout.
How do you inspect and what reports come with the parts?
Every part is inspected before shipment: raw material check, in-process monitoring, and final inspection. Reports are issued on request.
Depending on the feature, we use CMM, bore gauges, surface roughness testers, and dye penetrant for casting defects. The inspection plan is agreed before the first article.
What is the lead time for a new casting program?
Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours once design and material are confirmed, and machined parts ship in 3–5 days.
Foundry tooling adds its own lead time. We tell you that number up front so the schedule is built on real dates.
Is there a minimum order quantity?
No minimum. We run one prototype or a 10,000+ part run. The process and inspection plan scale with the batch.
Prototype parts are useful for checking datums and fixture behavior before committing to production tooling.
Will you sign an NDA before we send drawings?
Yes. Uploads are secure and confidential, and we sign an NDA on request before any files change hands.
We work with automotive and medical customers where drawing control is part of the contract, so document handling is routine for us.
Send the casting drawing and the machined drawing
We will come back with a process route, a tolerance review, and a quote.
12-hour quote100% inspectionNo minimum order quantity
