Film air release
Learn when trapped air needs perforation and how air release affects wrinkles, ballooning, seal stress and tunnel results.
Direct answer
Direct answer: Shrink film often needs a controlled air-escape route so trapped air can leave the pack while the tunnel recovers the film. If air cannot escape, the pack can balloon, wrinkle, stress the seal or cool into an uneven finish. Perforation, film choice and tunnel settings should therefore be tested together.
Competitor pages often call this a pin perforator or film perforation system. The important buying point is not the name of the component but whether the perforation pattern, film type, pack geometry and tunnel dwell produce a stable finished pack.
| Symptom | Possible air-release factor | What to check |
|---|---|---|
| Ballooned film leaving the tunnel | Not enough air evacuation or unsuitable perforation position. | Check perforation, film width, seal position and tunnel dwell. |
| Wrinkles around corners | Air cannot leave before the film tightens. | Test perforation density and pack orientation. |
| Seal stress or opened corners | Internal pressure acts on the seal during shrink. | Review seal strength, trapped air and film thickness together. |
| Visible holes or poor presentation | Perforation may be too visible or badly positioned. | Balance air release with retail appearance and label visibility. |
Buyer questions
No. Some film and pack formats release air adequately without extra perforation, while others need deliberate perforation to avoid ballooning or wrinkles. The decision should be made from real samples, film behaviour and the required finished appearance.
The best position depends on product orientation, film overlap, seal location and which face needs to look clean. Perforations should allow air to escape without putting visible holes on a critical display face when presentation matters.
Sometimes tunnel dwell and temperature changes improve the result, but they cannot always overcome poor air release. If trapped air is the primary issue, increasing heat can create distortion without producing a cleaner pack.
Related guidance: Shrink film perforation guide · Wrinkle troubleshooting · Tunnel airflow guide