Film handling
Separate roll alignment, film-path drag and static symptoms before changing L-sealer settings.
Direct answer
Direct answer: Centre-folded shrink film can walk sideways, wrinkle or cling when the roll is not centred, the film path is uneven, tension differs across the web, the forming area drags one layer, the roll is damaged or static attraction holds thin film to a surface. The most reliable check starts with the roll, unwind and guides, then observes where the film first stops running evenly.
Tracking and static can look similar but need different evidence. Mechanical tracking normally produces a repeatable sideways movement or diagonal crease linked to the roll path. Static can make a layer cling, hesitate, lift light products or attract dust, and may change with humidity, film or speed. Operators should record the first point where the film behaviour changes rather than compensating at several positions at once.
| Observation | Likely area to inspect | Useful evidence |
|---|---|---|
| Whole web moves steadily to one side | Roll centring, unwind alignment, guide position or uneven drag. | Video of the roll and film path at slow speed. |
| One layer clings or lifts intermittently | Static, contamination, humidity or film surface condition. | Film batch, environment and point where the layers separate. |
| Diagonal wrinkles appear after a guide | Guide angle, forming position or unequal web tension. | Mark the wrinkle origin before changing downstream settings. |
| Problem starts after a roll change | Roll damage, winding, width, centre-fold position or loading method. | Compare the previous and replacement roll specifications. |
Direct answer: The film normally walks sideways because the unwind, guide path or drag is not balanced across the web.
A roll that is off-centre, telescoped or unevenly wound can start the movement. Misaligned guides, contamination or one layer rubbing a surface can then amplify it. The first visible drift point is more useful than the final wrinkle location.
Direct answer: Static can attract the two film layers to each other or to machine surfaces, delaying separation and changing the way the web reaches the product.
The symptom may be intermittent and can vary with film, humidity, speed and contamination. Static-control measures must suit the machine and site; operators should not fit unapproved devices or defeat guarding to reach the film path.
Direct answer: The roll is a strong suspect when the problem begins immediately after a roll change or follows visible damage, telescoping, uneven edges or an off-centre fold.
Compare the new roll with a known good roll and confirm the width, fold, winding direction and material. A machine adjustment that compensates for one faulty roll can create a new problem when normal film is loaded.
Direct answer: The operator should confirm film identity, roll loading, cleanliness, free unwind, guide contact and the exact point where the film first drifts or clings.
Settings should be changed only within the approved operating procedure. Recording one change at a time prevents a film problem being hidden by unrelated timing, temperature or sensor adjustments.
Safety note: Film-path checks must follow the supplied instructions and site isolation procedure. Do not reach through guards, work near moving rollers or fit static-control equipment without competent approval.
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