01
Bore runout drifts across the batch
A single setup change moves the datum, and shaft bores start running out by 0.03 mm. Bearings press in tight on the first ten parts and loose on the last ten. Rework costs a week you did not plan for.
Auto Parts Processing
Auto Parts Processing Service for Production-Grade Components
We machine aluminum, stainless, steel and titanium components to ±0.005 mm. IATF 16949 process control, traceable material, and full inspection before every shipment.
±0.005 mm toleranceIATF 16949:2016No MOQ3–5 day shipping150 technicians12-hour DFM report
16Simultaneous 5-axis centers
127CNC machines across 3 plants
±0.005 mmAchievable tolerance
99.99%Qualification rate
Where it goes wrong
Four Failures That Show Up After Assembly
Most auto part problems are decided in the process plan, not on the bench.
02
Wall thickness collapses on thin ribs
Heat from roughing warps a 1.5 mm rib, so the finishing pass cuts air on one side and gouges the other. The part fails leak test or vibrates at speed.
03
Threads pull out at torque
Wrong pilot diameter or a dull tap leaves 60% thread engagement. The fastener holds on the bench, then strips when the line hits specified torque.
04
Surface finish fails the sealing spec
A Ra 3.2 μm as-machined face will not hold a gasket seal. Without a controlled finish callout, the mating surface leaks under pressure cycling.
How we hold the spec
A Process Plan Built Around Your Drawing
One setup strategy, one datum scheme, one inspection routine per part number.
Setup and datums
Fewer Setups, Tighter Position
Every component gets a written process plan before the first chip. We pick the datum from the drawing's functional faces, not from whatever the blank allows. On a 5-axis center, boring, facing and hole patterns come off one setup.
That removes the stacked error you get from three separate fixtures. Position tolerance stays inside ±0.005 mm across the run, and the first article matches part 500.
- 116 simultaneous 5-axis centersComplex geometry in a single setup.
- 2Ø400 mm rotary tableHole patterns and slots on multiple faces.
- 34,000 mm travelLong shafts and rails without repositioning.
Material and heat
Material Chosen for the Load Case
Brackets and housings usually run 6061-T6 or 7075-T6 when weight matters. Shafts and fasteners go to 4140, 4340 or 17-4PH when wear and fatigue govern. We check the certificate against the drawing before the stock is cut.
Thin-wall parts get stress-relieved stock and light finishing passes. That keeps flatness after heat treat instead of chasing it with a hammer and a press.
- 1Aluminum 6061, 7075, 6082Housings, brackets, covers.
- 2Steel 4140, 4340, 4130Shafts, gears, load-bearing links.
- 3Stainless 17-4PH, 316LCorrosion and high-strength fasteners.
Pick the right process
Which Cutting Route Fits Your Part
Match geometry and volume to the machine before you release the order.
| Part type | Best route | Why |
|---|---|---|
| Engine bracket, 3 faces | 5-axis mill | One setup, tight hole position |
| Turned shaft with cross-holes | Mill-turn center | No second op, no re-chuck error |
| Flat plate, 2 faces only | 3-axis mill | Lower cost, faster cycle |
| Prototype housing, 5 pieces | 5-axis + rapid prototyping | No hard fixture needed |
| 10,000+ simple bushings | CNC turning | Repeatable, low piece cost |
| Thin-wall cover, 1.2 mm | 5-axis, light finishing | Controlled deflection, no warp |
What we run
Services Behind the Processing Line
One supplier from first article to finished, plated, inspected parts.
01
5-Axis CNC Machining
Complex housings and brackets in one setup. 16 simultaneous 5-axis centers hold position on angled faces and contoured pockets.
02
CNC Milling & Turning
Mill-turn centers cut shafts, flanges and fittings without a second chucking. Fewer setups means less runout on bearing journals.
03
Rapid Prototyping
Functional prototypes for fit checks and test rigs. Same material and tolerance as the production route, so test data carries over.
04
Surface Finishing
Anodizing, electroless nickel, zinc plating, powder coat and black oxide. Sealing faces stay masked and within finish callout.
05
Sheet Metal Fabrication
Brackets, covers and heat shields when a bent part beats a machined one. Laser cut, formed and finished to the same drawing control.
06
Die Casting & 3D Printing
ADC12 housings in volume, or printed fixtures and prototype clips when the tooling budget is not there yet.
Scope and terms
What a Job Includes
| Item | Standard | Notes |
|---|---|---|
| Tolerance | ±0.005 mm | Tighter on request, part by part |
| Surface finish | Ra 0.8–1.6 μm | Ra 0.2–0.8 μm for sealing faces |
| Order quantity | No MOQ | From 1 prototype to 10,000+ |
| First article | Within 3–5 days | After drawing release |
| Inspection | 100% before shipment | Reports on request |
| Quote and DFM | Within 12 hours | Includes free DFM analysis |
Why GreatLight
Numbers We Can Back Up
The figures below come off our own equipment list and quality records.
±0.005 mm
Repeatable tolerance
Held across a run, not just on the first article. In-process checks catch drift before the batch is finished.
IATF 16949
Automotive process control
Documented setup, in-process monitoring and final inspection aligned to automotive quality expectations.
15Y
Machining since 2011
Three wholly-owned plants and 150 technicians in Dongguan, plus a Singapore facility.
12 h
Quote and DFM report
We read the drawing, flag thin walls and tight callouts, and send a quote the same working day.
24 h
Production start
Once the drawing is released and material is confirmed, the first setup can start within a day.
0 MOQ
One part or ten thousand
Prototype runs and volume runs use the same process plan, so the part does not change between them.
7,600 m²Manufacturing space
127CNC machines
99.99%Qualification rate
<2%Historical late-delivery rate
What the job demands
How We Meet Common Application Requirements
Engine and drivetrain brackets
Functional faces and bolt patterns need position that holds through heat cycles.
- ±0.005 mm position
- 6061-T6 / 7075-T6
- 5-axis, one setup
EV and battery-pack hardware
Housings and busbar brackets must stay flat and clear creepage distances.
- Flatness after finishing
- Anodized or plated
- 100% inspected
Shafts, pins and fittings
Bearing journals and seal faces carry the finish and roundness callouts.
- Ra 0.2–0.8 μm options
- 17-4PH / 4140
- Mill-turn, no re-chuck
Prototype and low-volume runs
Test rigs and pre-tooling builds ship without a hard fixture or tooling spend.
- No MOQ
- 3–5 day shipping
- Same process as volume
FAQs
Questions Engineers Ask Before Releasing an Order
What tolerance can you actually hold on a production run?
±0.005 mm is our standard achievable tolerance on machined features. It holds across a batch because we fix the datum scheme before cutting and check critical dimensions in process.
If your drawing calls for tighter than that on one or two features, tell us which ones. We will say whether the geometry and material support it.
Which materials do you machine for underhood and drivetrain parts?
Aluminum 6061-T6, 7075-T6 and 6082 for housings and brackets. Steel 4140, 4340 and 4130 for shafts and load-bearing links. Stainless 17-4PH and 316L where corrosion matters.
For high-temperature or high-load parts we also run titanium TC4 and Inconel. Material certificates are checked against the drawing before cutting.
How do you keep a thin-wall part from warping?
We use stress-relieved stock where the section is under about 2 mm, take lighter finishing passes, and control coolant and feed to limit heat input.
For parts that get heat treated after machining, we plan the sequence so final finishing happens after the stress relief, not before.
Can you match an existing part without a full CAD model?
Yes, if you send a sample or a scanned mesh plus the critical dimensions. We rebuild the model around the functional faces and confirm the callouts with you.
Reverse engineering works well for brackets and covers. It is a poor fit for parts where the internal geometry drives performance and cannot be measured.
What does the first article process look like?
We machine the first part to the released drawing, inspect it fully, and send the dimensional report before running the rest of the batch.
You approve the first article or mark what needs to change. Production parts then use the same setup and tooling as that approved piece.
How is surface finish specified and verified?
Give us the Ra value per face. As-machined is Ra 1.6–3.2 μm, high-finish is Ra 0.8–1.6 μm, and sealing or bearing faces can go to Ra 0.2–0.8 μm.
We verify with a surface roughness tester and record the reading. If a face will see a gasket or an O-ring, call it out at quote time.
Do you handle finishing and plating in-house or outsourced?
Both routes exist. Anodizing, plating, powder coating, black oxide, bead blasting and laser marking are all available as part of the order.
Finishing suppliers follow our drawing callouts, and we inspect the finished part against the same critical dimensions before it ships.
Is my design kept confidential?
Uploads are secure and confidential. We can sign an NDA before you send drawings if your process requires it.
Files are shared only with the engineers and machinists who need them to build the part.
Send Your Drawing, Get a Quote in 12 Hours
Upload a STEP or PDF and we will return pricing plus a free DFM analysis. No minimum order quantity, 100% inspection before shipment.
12-hour quote100% inspectionNo MOQNDA on request
