What changes when the cap stays attached?
A tethered closure is designed to stay attached to its container during normal opening and use. The attachment is an additional functional feature: the capping process must seat and seal the closure without damaging the part that keeps it connected. The cap may still use a screw thread, so tethering and screw capping are not opposing technologies.
Some closure manufacturers offer designs intended to minimise changes to existing equipment; that is a statement about those designs, not a guarantee for every capper. Treat this guide as a compatibility review, not confirmation that a particular Lancing model accepts an untested tethered cap.
Start with the bottle and cap drawing review, including the closed cap, attachment feature, tamper band and approved neck finish.
Separate closure changes from neck changes
A project that changes only the cap can have a different scope from one that also changes the bottle neck. Record which component revisions remain unchanged. A new neck finish can affect bottle guides, neck support and transfer parts even when the closure looks similar from above.
Compare the contact envelope rather than only the thread diameter. Mark where a chuck grips, where spindle wheels touch, which surfaces carry top load, and how the feeder track supports the closure. Then identify any contact that overlaps an attachment, slit or tamper feature. Do not remove or trim a functional feature to make a cap fit existing tooling.
A conversion review from hopper to finished bottle
| Stage | Evidence to request | Decision it supports |
|---|---|---|
| Bulk feeding | Production closures after normal storage, tipping and recirculation | Whether the cap can be sorted without catching or damaging features |
| Track and handover | Track-contact drawing and observed transfer to the bottle | Whether the existing feed path supports the new cap consistently |
| Application tooling | Chuck or wheel contact, head travel and bottle restraint | Whether change parts or revised settings are needed |
| Closed pack | Cap height, thread engagement, sealing and band condition | Whether application meets the agreed pack criteria |
| Opening and reclosure | Supplier-defined attachment, opening and resealing checks | Whether the consumer-use function survives machine application |
Plan a reversible changeover trial
Keep the current approved bottle and cap as the control format. Record its tooling, settings and quality checks before trialling the proposed closure. Use traceable component lots, identify every temporary change and agree who can authorise a return to normal production. A successful short demonstration should not silently become approval for all formats.
Run the proposed format through normal replenishment and stop/restart conditions, not only steady feeding. Separate damage introduced by bulk handling from damage created during tightening. Inspect both rejected and accepted-looking packs; an apparently straight cap may still have a damaged attachment.
The cap-feeder acceptance guide provides the disturbance-test structure. Use the existing retrofit page to define modification and handover responsibilities.
Questions about tethered-cap machinery
Does a tethered cap require a different capping principle?
Not necessarily. A threaded tethered cap still needs controlled thread engagement and seating. The deciding factors are the complete closure design, available gripping surface and machine contact. A press-on design requires its own application method; the attachment alone does not identify the correct machine.
Is changing the chuck always enough?
No. A chuck change may address one contact, but it cannot establish feeder compatibility, bottle support or finished-pack function. Ask for a component-by-component scope, including anything that remains conditional on samples, rather than assuming every existing line needs the same modification.
Is this only relevant to bottles sold in the UK?
No. The destination market and customer packaging specification both matter. EU single-use-plastics rules are one reason beverage producers use attached closures. Confirm the rules applying to the actual pack and market with the responsible compliance team; this page does not certify a bottle or extend EU rules automatically to every UK pack.
What should accompany a tethered-cap enquiry?
Send the current and proposed bottle, cap and neck drawings, labelled samples, capper and feeder identification, normal output requirement and the intended destination market. Include the closure supplier's application and opening criteria, plus any requirement to continue running the old format.
Reference material and next step
This is Lancing application-review guidance, not a declaration of compatibility or compliance. Primary references: BERICAP tethered-closure design and line-trial guidance, AROL on equipment-dependent tethered-cap conversion and European Commission background on attached beverage closures.
Compare the existing screw-capping routes before preparing a sample and quotation brief. A short initial enquiry is enough; detailed drawings can follow.