Problem & answerI-07
Bottles Without Foil Not Rejected (or Good Bottles Rejected)
Also covers: Foil (liner) detection sensor
Likely causes
- Foil sensor height not set for the bottle and cap (too far from the cap)
- Sensor sensitivity drifted
- Sensor not centred over the cap
- Reject device not working (air, timing)
- Metal close to the sensor causing false signals
How to fix it
- 1Stop the line.
- 2Segregate all bottles since the last successful foil challenge test; check each for a foil liner.
- 3Set the sensor height with the knob so the sensor sits just above the cap, centred over it.
- 4Challenge test: pass a capped bottle with a cap that has no foil. It must be detected and rejected. Pass a correct bottle: it must not be rejected.
- 5If the no-foil bottle passes, adjust sensitivity (authorised staff) and repeat the test.
- 6Check the reject device fires and removes the bottle.
- 7Record the test and actions; inform QA.
Technical note
The foil sensor checks every capped bottle for the aluminium foil liner inside the cap. A bottle without foil cannot be induction sealed and must be rejected. It is a key quality check: test it at start-up, after any adjustment and at the end of the batch.Photos
It is fixed when
No-foil test bottle rejected every time; good bottles pass.
Stop it coming back
- Challenge-test the foil sensor at start-up, after stops or adjustments and at batch end.
- Keep a marked no-foil test cap at the line.
Did this solve the problem?