01
Leaking flange after assembly
A sealing face that is not flat to within 0.05 mm across its length will not compress the gasket evenly. The leak shows up at the first hot test, and the whole batch needs rework or scrap.
Automotive & EV Machining
Automotive Engine Oil Pan CNC Machining
We machine aluminum and steel oil pans from one prototype to 10,000+ part runs. Sealing faces, bolt patterns and drain ports held to ±0.005 mm, with 5-axis drilling that reaches the deep sump walls in one setup.
IATF 16949:2016±0.005 mm tolerance16 five-axis centersNo minimum order12-hour quote100% inspection
16Simultaneous 5-axis centers
±0.005 mmAchievable tolerance
12 hQuote and DFM analysis
3–5 daysParts ship after start
Common failures
Where oil pan machining goes wrong
Most oil pan problems trace back to one of these four.
02
Drain plug threads strip
Milled threads or a drilled port that is not perpendicular to the boss face cut the thread depth short. The plug cross-threads on the line and the pan is rejected.
03
Baffle and windage tray fit
Internal baffles that need hand fitting burn assembly time. If the mounting pads are not located to the CAD within 0.1 mm, the tray sits proud and rattles.
04
Prototype schedule slips
A one-piece pan for a test engine cannot wait for a casting. Shops that only quote at high volume leave prototype builds without a supplier.
How we machine it
One setup for the sealing face, bolt pattern and ports
Fixture the pan once, cut the critical features together, then verify them.
5-axis setup
Sealing face and bolt holes from one datum
The rail that carries the gasket is the controlling feature on any automotive engine oil pan. We clamp the pan on its sump base and cut the rail, the bolt holes and the drain port in the same 5-axis setup. Nothing is repositioned between operations, so the hole pattern stays true to the sealing face instead of to a second fixture.
With 16 simultaneous 5-axis machining centers and a Ø400 mm rotary table, we reach angled walls and internal baffle pockets without rechucking. A typical 6061-T6 pan takes two operations: one for the rail, pan walls and port, one to open the interior and finish the mounting pads.
- 1Rail flatnessHeld to 0.05 mm across the full length on a 500 mm pan.
- 2Hole positionBolt circle located to the CAD datum within 0.1 mm.
- 3Single datumRail, holes and drain port cut without a second fixture.
Material and wall control
Thin walls that hold their shape
Oil pans are lightweight parts, and light means thin. Wall sections on a machined aluminum pan often run 3 to 4 mm, with ribs as thin as 2.5 mm. Cutting that without chatter or distortion depends on toolpath strategy and light finishing passes, not on running the spindle slower.
We machine 6061, 6061-T6, 7075 and ADC12 for aluminum pans, and 1018 or 4130 when a steel pan is specified. For prototype work we also machine HDPE and ABS to check fit and clearance before metal is cut. Surface finish lands between Ra 0.8 and 1.6 μm on sealing faces.
- 1Minimum wall2.5 mm on ribs, 3 mm on general pan walls.
- 2Materials6061-T6 and 7075 aluminum, 1018 and 4130 steel.
- 3Sealing finishRa 0.8–1.6 μm on gasket contact faces.
Process selection
Machined pan or cast pan?
Use this to decide which route fits your program.
| Factor | CNC machined pan | Die cast pan |
|---|---|---|
| Best for | Prototypes, low and mid volume | High volume, one fixed design |
| Tooling cost | None; cut from billet or plate | Pattern and die required |
| Lead time | 3–5 days after machining starts | Weeks for tooling, then casting |
| Design changes | Edit the program and recut | New tooling or die insert |
| Wall thickness | Down to 2.5 mm on ribs | Set by casting flow limits |
| Typical quantity | 1 to 10,000+ parts | Tens of thousands of parts |
What we do
Machining services for oil pan programs
One supplier for the pan and the parts around it.
01
5 Axis CNC Machining
Rail, bolt pattern and drain port cut in one setup on 16 simultaneous 5-axis centers.
02
4 Axis CNC Machining
Rotary work for baffle pockets and angled mounting bosses on 12 four-axis mills.
03
CNC Milling & Turning
Drain plugs, sensor bosses and threaded fittings turned to match the pan port.
04
Rapid Prototyping
One-piece pans and fit-check models machined from aluminum or plastic in days.
05
Sheet Metal Fabrication
Windage trays, baffle plates and gasket retainers formed and punched to the same datum.
06
Part Surface Finishing
Anodizing, powder coating, bead blasting and laser marking for part ID.
Scope and limits
What this service covers
Numbers apply to parts we have quoted and run.
| Item | Range or specification |
|---|---|
| Tolerance | ±0.005 mm on critical features |
| Maximum part size | 4,000 mm, travel 4,000 × 400 × 150 mm |
| Aluminum alloys | 6061, 6061-T6, 2024, 5052, 5083, 6063, 6082, 7075, ADC12 |
| Steel grades | 1018, 1045, 4130, 4140, 4340, A36, tool steel |
| Finish on seal faces | Ra 0.2–0.8 μm on request, Ra 0.8–1.6 μm standard |
| Inspection | 100% before shipment; reports on request |
| Minimum order | None; one prototype to 10,000+ part runs |
| Certifications | ISO 9001:2015, IATF 16949:2016, ISO 13485:2016, ISO 27001:2022 |
Why GreatLight
What you get from our shop floor
15Y
Machining since 2011
15 years in Dongguan with three wholly-owned plants and 150 technicians across 7,600 m².
±0.005 mm
Held on critical features
Rail flatness, hole position and port perpendicularity checked against the drawing on every run.
IATF
Automotive quality system
IATF 16949:2016 and ISO 9001:2015, with raw material checks, in-process monitoring and final inspection.
12 h
Quote and DFM analysis
Send a STEP file and we return pricing plus manufacturability notes within 12 hours.
1 pc
No minimum order
One prototype pan and a 10,000-part run go through the same fixturing and inspection steps.
99.99%
Qualification rate
Historical first-pass qualification across production runs, backed by 100% pre-shipment inspection.
127High-precision CNC machines
7,600 m²Manufacturing space
150Technicians on staff
<2%Historical late-delivery rate
Industry requirements
What these programs demand, and what we deliver
Passenger car prototype pans
One-off pans for test engines, cut from 6061-T6 billet and checked against the CAD datum before shipment.
- 1 to 5 parts
- 3–5 day ship
- ±0.005 mm
Diesel and industrial engine pans
Deep sump pans with internal baffle pockets. Rail flatness maintained across the full gasket length.
- Rail 0.05 mm
- Steel or aluminum
- 100% inspection
EV and hybrid housings
Machined covers and sump plates that seal against a machined face on the drive unit or engine block.
- Ra 0.8–1.6 μm
- Port perpendicular
- IATF 16949
Fit-check and tooling models
HDPE and ABS models machined to prove clearance around the subframe before metal pans are cut.
- Plastic models
- Days not weeks
- No tooling cost
FAQs
Questions engineers ask before quoting
What file formats do you need for a quote?
A STEP or IGES file is the most useful. We can also work from a native CAD file or a 2D drawing with tolerances marked.
Send whatever you have and we will tell you within 12 hours if anything is missing for an accurate quote.
Which aluminum alloy is best for a machined oil pan?
6061-T6 is the usual choice. It machines cleanly, holds a flat sealing rail, and takes anodizing well for corrosion resistance.
Use 7075 when you need higher strength at the same wall thickness. ADC12 is a casting alloy and only applies if the part is die cast rather than cut from plate.
How flat can you hold the gasket sealing rail?
We hold rail flatness to 0.05 mm across the full length on a 500 mm pan, measured after the finishing pass.
Tighter callouts are possible on shorter rails. Tell us the flatness specification on the drawing and we will confirm it during DFM review.
Can you machine the drain plug thread in the same setup?
Yes. The drain port and its boss are cut in the same 5-axis setup as the sealing rail, so the thread axis stays perpendicular to the boss face.
We can also supply the matching drain plug turned on our mill-turn centers.
What is the smallest quantity you will run?
One piece. There is no minimum order quantity.
A single prototype pan and a 10,000-part production run go through the same material check, in-process monitoring and final inspection.
Do you handle the surface finish as well as the machining?
Yes. Anodizing, powder coating, black oxide, bead blasting and laser marking are all available in house or through our finishing partners.
For oil pans, anodizing or powder coating is the common choice. Mask sealing faces before coating if the gasket needs bare metal contact.
How do you keep drawings and CAD files confidential?
Uploads are secure and confidential. We hold ISO 27001:2022 for information security.
An NDA is available on request if your program needs one before files are shared.
What inspection data comes with the parts?
Every part is inspected before shipment. Raw material certificates are kept on file and inspection reports are available on request.
For automotive programs we can record rail flatness, hole position and port perpendicularity against the drawing.
Send us your oil pan drawing
Upload a STEP file and get pricing, a DFM review and a machining plan within 12 hours.
12-hour quote100% inspectionNo minimum orderNDA on request
