Quality inspection on a stainless bottle is a sequence of eight checks that run from incoming material to the packed container, and the order matters: a defect caught at incoming material costs a phone call, and the same defect caught after packing costs a container. The one check that cannot be done by sampling is the vacuum test, because a failed seal is intermittent.
The eight control points
- Incoming material. Grade confirmed against the declaration before anything is formed.
- Forming and drawing. Wall thickness and dimension against the specification.
- Welding and seam. The seam is a common failure origin, so it is checked as it is made.
- Vacuum and leak test. Every piece, not a sample — see below.
- Coating. Adhesion and colour against the agreed tolerance.
- Decoration. Print registration, position and coverage.
- Assembly and lid fit. The item tested as the customer receives it, not as parts.
- Packing and carton. Quantity per carton, carton condition, and the label against the order.
Why per-piece testing, not batch sampling
Sampling works when a defect is evenly distributed. A vacuum seal is not: it fails at a limited number of points and intermittently, so a batch sample can pass on a run that contains leakers. The only inspection that catches that is a line test on every piece, and it is the claim we publish — every piece, not a sample. If you are comparing suppliers and only ask one question, ask this one.
What a buyer can inspect without visiting
| Evidence | Proves | Does not prove |
|---|---|---|
| Approved sample, photographed | The reference exists and is dated | That production matched it |
| Line video of the vacuum test | The test runs on the line | That it ran on your run |
| Carton and label photographs | Pack-out against the order | Condition inside the carton |
| Third-party inspection | An independent record of the run | Nothing about the units not sampled |
Questions buyers ask
Do I need a third-party inspection?
Above a certain order value most importers commission one, and the useful version is an inspection during production rather than after packing — after packing it can only tell you what to do with the container.
What is the acceptance quality level?
It should be written into the order. The QC checklist sets out the sampling table we work to and the stages it applies to.
What happens if the container fails?
That is a documented answer, not an improvised one — ask for it before the first order, because it is the question whose answer tells you most about the supplier.
The quality page names the standards each market requires, and the audit page records how the checks are kept honest.
