Irregular products
Assess puncture risk, film bridging, product stability, orientation and support with representative packs.
Direct answer
Direct answer: An irregular product can be L-sealed when the film can travel around it, close without snagging and shrink without concentrating unacceptable stress on corners, protrusions or unsupported openings. Dimensions alone do not prove this. Product orientation, edge radius, stability, film properties, air evacuation, support and the required finish must be tested together.
As shrink film recovers, it pulls towards the product. A sharp corner can act as a stress concentrator, while a handle, cut-out or open centre can cause the film to bridge and pull in an unexpected direction. Loosely grouped parts can also move before the film has stabilised. The objective should be defined: cosmetic retail finish, dust protection, tamper indication or grouping may lead to different acceptable results.
| Pack feature | Possible effect | Evidence to prepare |
|---|---|---|
| Sharp corner or burr | Puncture, whitening or local thinning as the film contracts. | Close photographs and the most severe production sample. |
| Handle, cut-out or open centre | Film bridging, trapped air or uneven pull around the opening. | Running orientation and required access after wrapping. |
| Loose grouped components | Movement, separation or a changing outer envelope. | Worst-case group arrangement and handling method. |
| Flexible or compressible surface | Indentation, conveyor marks or distorted presentation. | Approved contact pressure and cooled pack comparison. |
Direct answer: Sharp corners concentrate the film tension into a small area while the material is hot and recovering.
The risk is affected by edge radius, film properties, amount of film, tunnel conditions and contact during transfer. A corner that appears safe on an unshrunk bag may puncture only when the film pulls tight in the tunnel or during cooling.
Direct answer: No. A thicker or stronger film may improve resistance, but it can also need different sealing and shrinking conditions and may still fail on a burr or severe point.
The product edge, orientation, support and required finish should be reviewed first. The correct film must be demonstrated on the real line rather than selected from thickness alone.
Direct answer: Test the feature in its real running orientation and inspect how film, trapped air and shrink force behave around the opening.
The trial should confirm whether the opening must remain clear, whether the film may bridge it and whether the pack can transfer without snagging. Include the largest opening and the least rigid sample.
Direct answer: A tray or insert is worth considering when it creates a stable, repeatable outer envelope or shields a surface that the film cannot contact safely.
The added component changes pack dimensions, material use and handling, so it should be included in the trial and quotation. It should not be added merely to make an unsuitable process appear workable without reviewing alternatives.
Scope note: Final film and machine suitability depends on representative samples. Remove burrs and unsafe edges through the product design or approved packing method rather than relying on the film as a protective guard.
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