Quality control
Four gates. One of them is random.
A defect caught after coating costs about ten times what it costs to catch before. So the plan is built around catching it early, and then proving it with a document you can attach to a claim.
Gate 1 — incoming material
Nothing is released to a line until the material matches the drawing and the grade matches the certificate.
- Steel. Grade check (304 or 316) against the mill certificate, thickness measured on a sample per coil, surface inspected for lamination and scratches.
- Plastic resin. Grade and lot recorded — Tritan, PP or AS. A resin substitution is the single most common cause of a taste complaint, so the lot number goes on the batch record.
- Silicone and lids. Hardness and smell check. Gaskets are torque-tested on a sample of the incoming lot.
- Mould. Cavity inspection and a first-off shot before the run is released.
Gate 2 — in process
This is where a factory either has a system or has an opinion. Ours is a check sheet per station, signed per shift:
- Weld seam: visual and vacuum loss on 100% of vacuum bodies, not a sample.
- Wall thickness and capacity: measured against the drawing every 2 hours.
- Coating: film thickness, colour against the approved standard, and cross-hatch adhesion per batch.
- Print: registration, cure test and a wash test on the first 50 pieces of every setup.
Gate 3 — performance
Every order runs the same five tests before it can be packed. The numbers are the acceptance criteria, not marketing.
| Test | Method | Acceptance |
|---|---|---|
| Leak | Inverted, filled, 30 min | No seepage at the seam or the lid thread |
| Insulation | Boiling water, 24 h ambient | ≥ 62 °C retained for a 500 ml vacuum body |
| Cold retention | Ice water, 24 h ambient | Ice still present at 24 h for double-wall |
| Coating adhesion | Cross-hatch, ASTM D3359 | Class 4B or better after 500 dishwasher cycles |
| Drop | Packed carton, 80 cm, 6 faces | No unit damage, carton intact |
Gate 4 — pre-shipment
Between 5% and 20% of finished pieces are pulled at random by international sampling standard, depending on the order value and the buyer's history. The inspector checks measurement, appearance, function and packaging, then signs the AQL 2.5 sheet. Photographs of the actual cartons go to the buyer before the container is sealed.
Batch record, inspection sheet, material certificate, and photographs of the packed cartons. If a claim is ever raised, these four documents are the defence — or the admission.
When something goes wrong
Send photographs and the batch number from the carton label. We open the batch record, identify the station, and answer within two business days with one of three outcomes: replacement, credit, or an explanation of why the goods are within the agreed specification. The third answer is the one buyers find hardest to get elsewhere, and the one that saves the most arguments later.
Third-party inspection
SGS, TÜV, Bureau Veritas and Intertek are all welcome, and we will schedule the line around the inspector's date. We do not charge for access to the plant, and we do not ask to see the report first.
Want the inspection sheet before you order?
We will send the blank AQL form and the batch record template. If your QA team wants an extra test, add it to the spec and we will price it.