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Why you should not reuse (3 technical reasons)
When a bottle passes through the capper and comes out without a cap, the natural temptation on the line is to put the cap on by hand and send it to palletizing. Don't. There are three technical reasons to discard the bottle:
- The chuck may have damaged the bottle finish. The chuck surface contacts the upper edge of the cap — if the cap was not there, the chuck touched the glass/plastic directly. The damage results in a high cap or in leakage and loss of carbonation in the next use.
- Contamination risk. The chuck may carry lubricating grease or other contaminant that deposits on the finish or inside the bottle.
- On some C.I.H. designs, the ejector pin may enter the bottle and contaminate the product.
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Why you should not hand-apply a cap
Caps must not be applied by hand — they would not be applied with the proper force and vertical load, resulting in poor sealing or in caps hard to remove by the consumer (excessive removal torque due to irregular application). It is a quality defect that reaches the market disguised as "sealed cap".
Possible causes — Cap
| Item | Cause | Solution |
|---|---|---|
| 12.1.1 | Cap with broken bands. | See broken band diagnosis. Caps without a band fall through the chute before reaching the head. |
Possible causes — Capper (11 items)
Most causes are cross-references to other guide problems — confirming that bottle without cap is a symptom, not a root cause:
| Item | Cause | Solution |
|---|---|---|
| 12.3.1 | Misadjusted chute. | Minimum clearance of 1 mm in band diameter and 2 mm in height — see chute diagnosis. |
| 12.3.2 | Foreign material in cap descent. | Clean the channels. |
| 12.3.3 (P.O.) | Turret or cap launcher too high. | Check turret reference and launcher opening (~25.4 mm). |
| 12.3.4 | Bottle control guide and star wheels out of position. | Review star wheel sync and part formats. |
| 12.3.5 (C.I.H.) | Worn O-rings or balls stuck in the chucks. | Check free ball movement; replace O-rings if needed. |
| 12.3.6 | Incorrect chuck. | Confirm the chuck type in use. |
| 12.3.7 (C.I.H.) | Ejector pin spring broken or compressed. | Replace the spring. |
| 12.3.8 | Defective or misadjusted signal to the cap-release cylinder. Damaged bottle sensor. | Adjust the signal so the cylinder delivers the cap together with the bottle. Replace defective sensors. |
| 12.3.9 | Foreign objects or inverted cap stuck in the chuck. | Clean the chuck and investigate the root cause of the inversion — see inverted caps. |
| 12.3.10 | Inverted cap in descent blocked by the containment star wheel. | Adjust the sorter disc — see related post. |
| 12.3.11 (C.I.H.) | Incorrect clearance between band and transfer plate. | 1 to 1.5 mm on CSI equipment with PCO cam. |
Next step
Bottle without cap is the defect that crosses with all the previous problems. When it appears, it signals that there is an upstream problem — chute, sorter, chuck or capping head — and it is often associated with cocked cap at the capper on adjacent heads. That is why the complete technical guide is the most efficient reference: it connects the 13 defects so you can navigate from symptom to root cause in a single lookup.
Guide to Cap Application Problems
The 13 most common capper failures — diagnosis, root cause and correction. Free technical material.
Download the full guide →