Testing: What We Check Before a Container Leaves
A sample that looks right and leaks in a carton is not a sample. These are the checks that catch it while it is still cheap to fix.
On the Moulding Line
| Check | How | Frequency |
|---|---|---|
| Weight | 0.01 g balance | Per cavity, hourly |
| Wall | Micrometer at four points | Hourly |
| Neck | Go / no-go gauge | Per batch |
| Leak | 100 % on pumps, sample on bottles | Per batch |
| Appearance | Visual against a signed master | Per batch |
On the Assembly
For a multi-part pack the checks move to the joints: torque on each thread, O-ring presence and seating, and a vacuum hold on the finished assembly. A pack that passes each part and fails the assembly is usually a tolerance stack issue, not a part defect — which is why the assembly check is the one that matters.
Transit and Drop
Cartons are tested to a drop height agreed with the customer — commonly 1.2 m on a corner and an edge, filled to the shipping weight. Screenshot the failure and the fix is usually a change in the carton, not the bottle.
What Is Not Our Test
We are not a cosmetics lab. Stability, challenge testing and the finished-product safety assessment belong to the brand and its lab. We supply the packaging declaration and the migration report; we do not sign off a formula.
Being clear about that boundary is part of the service — a supplier who promises both is either guessing or subcontracting something they do not control.
The Sample Round
T1 samples come in 7–10 days. Test them filled, with the real closure and the real formula: fill, cap, invert 24 hours, shake, drop. Roughly half of first samples pass on the first look; the rest need a texture change, a wall adjustment or a thread tweak. Each round is 5–7 days.
Want the Check List as a PDF?
Send a note and we return the incoming-inspection sheet we use.