Seal quality troubleshooting

Shrink wrap seal quality guide

Seal quality problems can come from the sealer, film, product handling or tunnel. A structured check helps identify whether the issue is temperature, dwell time, film size, product shape or transfer.

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Shrink wrap seal quality guide for L sealers — Shrink wrap seal quality guide guidance from Lancing UK.

Weak or split seals

Check sealing temperature, dwell time, film contamination, seal wire condition and whether the product is pulling the film during transfer.

Check temperature and dwell time
Inspect sealing wire or blade
Confirm film width and perforation
Balance tunnel heat and airflow

Burnt or brittle film

Excessive temperature, too much dwell time or unsuitable film can create brittle seals or holes.

Loose corners after tunnel

Loose corners are often caused by too much film, poor perforation, insufficient airflow or incorrect tunnel dwell rather than the seal alone.

Specification information to send

Product	Send length, width, height, weight, photos and the largest and smallest pack sizes.
Film and finish	Confirm whether the priority is retail presentation, transit strength, tamper evidence or product protection.
Output	Confirm target packs per minute, daily volume, loading method and whether the product arrives from another machine.
Site	Confirm floor space, power, compressed air, conveyor height, access and any upstream or downstream equipment.

FAQ

Shrink wrap seal quality guide FAQs

Why do seals split after the tunnel?

The seal may be weak, the film may be under stress, or tunnel heat may be exposing a poor seal.

Why does film burn on the seal?

Temperature or dwell may be too high, or the film may not suit the setting.

How do I improve loose corners?

Review film width, perforation, tunnel airflow, belt speed and product spacing.