Phase Change Cooling System Specification Example for City Buses: Fixed Type
Phase Change Cooling System Specification Example for City Buses: Fixed Type
This is a worked specification for phase change cooling system in a fixed type 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 fixed type 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 | Phase Change Cooling System |
|---|---|
| Application | City Buses |
| Version | Fixed Type |
| Base material | PU Leather |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.5 mm |
| Finish | powder coated |
| MOQ | 500 pieces per specification |
| Sampling | 10 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 — PU Leather, 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
- robot welding
- rubber vulcanisation
- anodising
- heat treatment
- cold forging
- ultrasonic cleaning
Where this example applies
Programmes that run fixed type most often specify this build for city buses. Related applications include passenger cars, emergency vehicles, export programmes, courier fleets, dealership service.
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
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.
What is the minimum order quantity?
The standard MOQ is 500 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.
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
Tell us the model, the fitment and the quantity and we will hold a production slot for you.
