Spindle capping machines
Compare the main automatic, compact and semi-automatic capping routes.
Cap-height evidence
How do you control cap height on screw-capped bottles?
Cap height is a visible indicator of thread engagement and closure position.
Direct answer
How do you control cap height on screw-capped bottles?
Cap height is controlled by using compatible bottle and cap samples, setting cap presentation squarely, supporting the bottle during tightening and checking the finished position against approved packs. A cap-height check should be used with torque or integrity evidence rather than as the only acceptance test.
What cap-height variation can indicate
| Observation | Possible cause | Next check |
|---|---|---|
| One side higher | Tilted cap, cross-thread or poor handover. | Slow-speed view of cap start and neck finish. |
| All caps high | Insufficient thread engagement or stopping before final position. | Approved hand-capped reference and setting record. |
| Caps low or damaged | Excessive force, incompatible closure or wrong contact area. | Cap condition, liner contact and torque evidence. |
Related guidance
Continue the specification
FAT checklist
Plan evidence for sample testing, acceptance and handover.
Ask Lancing to review the pack
Send bottle, cap, samples, target output and any known fault evidence.
Agree the cap-height reference before comparing results
Define the physical points used to assess the cap position on an approved pack. Record whether the check concerns overall height, the visible relationship to a neck feature or a difference around the circumference. This avoids comparing measurements that use different reference points.
Keep cap-height observations beside the other agreed closure checks. If the position changes, retain affected packs and note the bottle and cap batch references, setup and production event. The observation should guide an investigation rather than become an unsupported diagnosis on its own.
- Reference samples
- Retain labelled accepted examples and, where useful, agreed examples of visible faults for operator comparison.
- Measurement consistency
- Ask the packaging or quality team to specify the method, timing and acceptance limits appropriate to the actual pack.
Can a correctly positioned cap still need further checks?
Yes. Finished position addresses only the requirement it measures. Follow the agreed torque, function or integrity checks for the package as applicable, and avoid treating one visual measurement as approval of every closure property.