A film description needs more than “PE shrink film”
Polyethylene films can differ in thickness, formulation, shrink direction, shrink force, sealing behaviour, slip, clarity, colour, recycled content, winding quality and printing. A roll that fits physically may still produce a different seal or tunnel result. Treat the approved film and machine settings as a combined process specification.
The current LU-SPL4 reference lists PE shrink film, a film thickness range of 0.03–0.25 mm and a maximum roll width of 560 mm. Those figures describe the published model reference; they do not select the correct film for every pack. Final width, thickness and grade must be checked against bundle dimensions, product edges, weight, tunnel behaviour and the finished-pack requirement.
| Film item | Information to record | Why it matters |
|---|---|---|
| Supplier and grade | Manufacturer, product code, technical data sheet and batch or roll identification. | Allows repeat supply and investigation of material changes. |
| Thickness | Nominal thickness and agreed tolerance, using the supplier's unit and test method. | Influences strength, sealing, heat response and material use. |
| Roll width | Actual width required for the approved bundle and wrapper film path. | Controls wrap coverage, overlap, side opening and tracking. |
| Roll construction | Core size, maximum outer diameter, roll weight, winding direction and film presentation. | Must be compatible with the unwind, lifting method and film feed. |
| Shrink behaviour | Supplier data for the intended material and trial evidence on the actual tunnel. | Different grades recover differently with heat, dwell and airflow. |
| Sealing behaviour | Approved seal settings or operating window and the required seal condition. | Supports repeatable seals without open areas or damage. |
| Surface and printing | Slip, treatment, print, registration marks, ink and required presentation direction where applicable. | Affects tracking, collation contact and printed-film alignment. |
| Storage and handling | Supplier requirements for temperature, sunlight, moisture, stacking, age and acclimatisation. | Protects roll condition and reduces unexplained process variation. |
Confirm width from the real pack and film path
Provide the finished bundle length, width and height with a marked conveyor direction, plus the intended seal location and acceptable side openings. Film width depends on how the sleeve is formed around that geometry and the overlap required by the machine. Do not calculate from container diameter alone when products are grouped in rows, supported by a tray or have irregular overhang.
Control supplier or grade changes
When a film changes, compare the technical data and repeat enough of the approved trial to confirm seal continuity, shrink finish, product condition, cooling and handling integrity. Update the film reference and settings only after acceptance. Keep old and new rolls clearly separated during the evaluation so results are attributable.