Car Door Assembly Specification Example for City Buses: Upgraded Version
Car Door Assembly Specification Example for City Buses: Upgraded Version
This is a worked specification for car door assembly in a upgraded version programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The upgraded version version exists because the duty cycle on city buses is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually warranty claims traced back to a single lot.
Example specification
| Item | Car Door Assembly |
|---|---|
| Application | City Buses |
| Version | Upgraded Version |
| Base material | Stainless Steel |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.2 mm |
| Finish | powder coated |
| MOQ | 2,000 pieces per specification |
| Sampling | 14 working days, 3 days per revision |
| Compliance | SAE J431 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Stainless Steel, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.
Processes involved
- heat treatment
- cold forging
- surface grinding
- ultrasonic cleaning
- laser cutting
- anodising
Where this example applies
Programmes that run upgraded version most often specify this build for city buses. Related applications include assembly programmes, off-road bikes, dealership service, long-haul trucks, boat trailers.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 1.5 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
What testing is included?
Standard lots ship with dimensional and hardness reports. SAE J431 documentation is issued with the shipment when your market requires it.
How long does sampling take?
Samples leave the factory in 14 working days, and each revision round adds about 3 days once you have seen the first piece.
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the SAE J431-compliant build instead of a fresh interpretation.
Tell us the model, the fitment and the quantity and we will hold a production slot for you.
