Home / Knowledge / Specifying a vial closure system
Specifying a vial closure system
The vial, the stopper and the cap are one system, and a mismatch is discovered by a filling machine rather than by a goods-in inspector.
A closure system has three interfaces. The stopper plug has to fit the vial bore; the stopper flange has to sit on the vial neck; and the cap skirt has to crimp over both. Each of those is a dimensional relationship rather than a property of any single component.
That is why buying the three separately is risky even when each one meets its own drawing. Three components can all be within tolerance individually and still stack up to a closure that leaks, because tolerances add rather than cancel.
The failure mode is also expensive in a specific way. It appears on the filling line, after the vials have been filled, which means the product inside is at risk as well as the schedule. Nobody discovers a stopper problem in the warehouse.
The practical rule is to specify the neck finish and the nominal volume, order the three together, and ask the supplier to confirm the combination rather than each item. What you want on the confirmation is a statement that the set has been supplied together before, not three separate dimensional reports.
Specifications
| Three interfaces | Plug to bore, flange to neck, cap to both |
|---|---|
| Risk | Tolerances add across three components |
| Discovered | On the filling line, after filling |
| Ask for | Confirmation of the set, not of each item |
Related Products
Blood tube additives and cap colours
Cap colour is a convention, not a standard, and it is the most common source of confusion in a cross-border tube order.
PPE standards by destination
Two identically described masks can be certified against different test methods, and only one of them may be acceptable where you sell.
Analyzer and strip continuity
An instrument is bought once and fed every month, so supply continuity of the consumable matters more than the instrument specification.
Send the SKU and target quantity
Name the item, the size or additive, the quantity and the destination market. We reply from the catalog rather than with a form to fill in.