Car Door Assembly Specification Example for Utility Trailers: Vented Design
Car Door Assembly Specification Example for Utility Trailers: Vented Design
This is a worked specification for car door assembly in a vented design 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 vented design version exists because the duty cycle on utility trailers is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually packing that arrived crushed at the port.

Example specification
| Item | Car Door Assembly |
|---|---|
| Application | Utility Trailers |
| Version | Vented Design |
| Base material | Silicone |
| Controlled dimensions | 6 key dimensions, recorded per lot |
| Tolerance band | ±0.05 mm |
| Finish | zinc plated |
| MOQ | 3,000 pieces per specification |
| Sampling | 10 working days, 5 days per revision |
| Compliance | ISO 9001 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Silicone, 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
- electroplating
- CNC machining
- shot blasting
- assembly line testing
- gravity casting
- rubber vulcanisation
Where this example applies
Programmes that run vented design most often specify this build for utility trailers. Related applications include three-wheelers, utility trailers, delivery vans, rental motorcycles, long-haul trucks.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 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 is the minimum order quantity?
The standard MOQ is 3000 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
Do you handle mixed containers?
Yes. Most programmes consolidate several part numbers into one container to keep freight sensible at 3000 pieces per line.
How long does sampling take?
Samples leave the factory in 10 working days, and each revision round adds about 5 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.
Send the specification you are working to and we will confirm what we can match, what we would change and why.



