Packaging faults should be investigated from evidence, not from the first visible symptom. Preserve failed and good samples, identify component lots and machine settings, define when the defect appears, and change one factor at a time. A leak, wrinkle or poor seal can have several interacting causes, so the correct action depends on the actual pack and process.
Use the same fault-isolation sequence
| Step | Action | Record |
|---|---|---|
| Contain | Stop affected stock from moving and retain failed and good samples | Product and component lots, time, line and quantity affected |
| Describe | State the defect, location, frequency and point of discovery | Photographs, measurements and consistent terminology |
| Compare | Check component, product, settings, operator, environment and storage changes | Last known good versus first known bad condition |
| Test | Change one factor or use a controlled matrix | Method, samples, settings and result |
| Correct and verify | Implement the approved action and monitor production | Revised specification, setting or procedure and effectiveness check |
Why does a pack leak even when the components look undamaged?
A leak can arise from a small dimensional mismatch, contaminated seal surface, damaged liner, poor heat seal, incorrect application, product attack, stress or handling damage. Visual inspection alone may miss the path.
Map the leak location, compare component lots and settings, inspect mating surfaces and use a test appropriate to the pack. Do not tighten a cap or increase heat automatically; that can create a different failure.
What causes bottles to panel, distort or become unstable?
Bottle distortion can be linked to product interaction, temperature, pressure change, wall distribution, storage load, conveying pressure or an incompatible process. Base instability may also come from deformation during transport or storage.
Compare empty and filled samples, check the timing of the defect, review product and temperature conditions, and confirm the bottle specification before changing machine guides.
Why do caps loosen, cross-thread or leak?
Possible causes include mismatched finishes, damaged threads, cap presentation, poor pickup, incorrect head alignment, variable application, liner displacement, contamination or container instability. The fault may originate before the capping head.
Inspect bottle and cap drawings, feeding, orientation, head condition, applied result and leak pattern. Test both components from controlled lots.
Why do labels wrinkle, lift or flag?
Label defects can result from container taper or flex, surface contamination, condensation, the wrong adhesive, poor label geometry, web tension, misalignment or insufficient wipe-down. The label may also be applied outside its intended temperature or surface condition.
Compare hand and machine application, inspect the container surface and label roll, and record the time at which the defect develops.
Why do pouch seals or shrink-film packs fail inconsistently?
Inconsistent results often reflect variable presentation, contamination, thickness, tension, temperature, dwell, pressure, airflow or product position rather than one fixed setting. Starts, stops and speed changes can expose a narrow process window.
Sample across the roll and production period, record actual settings and conditions, and check material lot, seal areas, machine contact surfaces and downstream handling.
Evidence to retain with a fault report
- Failed, borderline and accepted samples.
- Product and every packaging component lot.
- Machine recipe, actual settings, operator and production time.
- Photographs, measurements and defect frequency.
- Storage, transport and supplier changes since the last accepted run.