In this article
Why caps jam: 3 possible origins
When the cap feeding flow fails, the whole line stops — or worse, the capper keeps spinning and produces bottles without caps. Flow defects concentrate in three origins:
- The cap itself — deformations, shell flash (injection flash), broken bands stuck in the channels.
- Foreign material — foreign objects in the channels, cap remnants, production debris.
- Chute adjustment — wrong clearances, inadequate sorter speed, P.O. air pressure outside the window.
Chapter 9 of the packaging technical guide addresses each origin in parallel. Summary below.
Possible causes — Cap
| Item | Cause | Solution |
|---|---|---|
| 9.1.1 | Deformed caps. | Change the lot, engage supplier technical support. |
| 9.1.2 | Shell flash (injection flash). | Change the lot, engage technical support. |
| 9.1.3 | Caps with broken bands. | See broken band diagnosis — fixing the root cause upstream solves the jam. |
Possible causes — Capper
| Item | Cause | Solution |
|---|---|---|
| 9.3.1 | Foreign material in the channels. | Clean the feeding channels removing anything that prevents free flow. |
| 9.3.2 | Misadjusted chute. | Clearance minimum 1 mm in band diameter and 2 mm in height. |
| 9.3.3 (P.O.) | Air pressure too low. | Adjust air pressure to correctly position the cap in the launcher arms. |
| 9.3.4 | Disc start/stop times misadjusted. | Adjust sensors so the disc stops with the chute full and runs when the upper sensor detects lack of caps. |
| 9.3.5 | Cap level in the sorter too high. | Keep between 1/4 and 1/3 of total capacity. |
| 9.3.6 | Sorter disc speed too low. | Sorter disc speed should be, up to 8 heads: 22-25 rpm. Above 8: 28-30 rpm. |
| 9.3.7 | Cap ejection mechanism misadjusted. | Inspect the system. Check that it pushes caps stuck between discs. |
Correct chute setup
calha-encapsulador-detalhe.jpeg
Band diameter clearance: ≥ 1 mm
Height clearance: ≥ 2 mm
Sorter speed: 22-30 rpm (depends on number of heads)
Cap level in the sorter: 1/4 to 1/3 of capacity
These 4 numbers, checked in sequence, solve most jams without needing parts replacement. When the problem persists even with everything in the window, suspect foreign material (even small) or a defective cap lot. In some cases, assembly wear justifies replacement with a new cap sorter, especially when the discs show irregular gap.
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Next step
Chute jamming generates two associated symptoms: inverted caps at the sorter and bottles without caps. Diagnosing the feed flow corrects the three cascading problems.
Guide to Cap Application Problems
The 13 most common capper failures — diagnosis, root cause and correction. Free technical material.
Download the full guide →