Air Auto Filter Specification Example for City Buses: Two-Piece Construction
Air Auto Filter Specification Example for City Buses: Two-Piece Construction
This is a worked specification for air auto filter in a two-piece construction 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 two-piece construction 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 lead time that slipped twice before bulk started.
Example specification
| Item | Air Auto Filter |
|---|---|
| Application | City Buses |
| Version | Two-Piece Construction |
| Base material | Nylon 66 |
| Controlled dimensions | 6 key dimensions, recorded per lot |
| Tolerance band | ±0.2 mm |
| Finish | zinc plated |
| MOQ | 1,000 pieces per specification |
| Sampling | 7 working days, 3 days per revision |
| Compliance | DOT |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Nylon 66, 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
- shot blasting
- electroplating
- robot welding
- die casting
- precision stamping
- rubber vulcanisation
Where this example applies
Programmes that run two-piece construction most often specify this build for city buses. Related applications include three-wheelers, delivery vans, dealership service, municipal fleets, scooter fleets.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 2.5 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. DOT documentation is issued with the shipment when your market requires it.
What is the minimum order quantity?
The standard MOQ is 1000 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
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.
How long does sampling take?
Samples leave the factory in 7 working days, and each revision round adds about 3 days once you have seen the first piece.
Send the part number, the annual volume and the target market, and we will come back with a specification and a sampling plan.
