Shrink film is a film that contracts when heated to wrap a product tightly. If you choose the wrong width, the film may not cover the product, or excess film may wrinkle at the corners. The wrong thickness can tear around a heavy group or add unnecessary cost for a light product. This guide explains how to consider width and thickness before requesting a quote.
Choose the film format first
Tube shrink film is a tubular film sealed along both edges; the product group is placed inside it. It is useful for repeated runs of products in the same size, such as groups of bottles and boxes. Centre-fold film is folded down the middle; the product is placed between the two layers and the open edges are sealed. Businesses using sealing machines may prefer this format.
Sheet shrink film is a single layer wrapped around the product. It offers more flexibility for large or variable-size products such as furniture, panels and doors. The right format depends on your product and machine; if you are unsure, you can ask for a quote for both.
How do you calculate the width of tube shrink film?
The width of tube shrink film is the width of the flattened tube. When opened, the tube’s circumference is twice this width. The film should comfortably cover the circumference of the group in the wrapping direction, with allowance for shrinkage.
Add the group’s two dimensions in the wrapping direction (usually width and height); this total is the minimum tube width. Add an allowance so the product fits into the tube easily and to allow for shrinkage. The required allowance depends on the film’s shrink behaviour, the product’s shape and the heating equipment, so confirm the final size by testing with the actual product.
Illustrative example: The figures below are for explaining the calculation only; they are not a test result or recommended size for a Mertan product.
| Calculation step | Example |
|---|---|
| Group dimensions (width × length × height) | 18 × 27 × 31 cm |
| Wrapping direction | The film runs along the length; width and height are wrapped |
| Total of dimensions around the group | 18 + 31 = 49 cm |
| Assumed 10% allowance | 49 × 1.10 ≈ 54 cm |
| Tube width to include in the quote | Approximately 54 cm; confirm through testing |
For bottle groups, it is common to leave the film open at the sides (leaving a window). In this case, calculate the film length separately based on the group’s length, the size of the opening and the cutting allowance.
How do you calculate the width of sheet shrink film?
For sheet film, the width is determined by the product’s circumference in the wrapping direction and the allowance needed to seal the ends. Furniture and panels are usually wrapped along their long edge; an extra allowance is needed so the seams overlap. If you package several products in different sizes, using one shared width instead of a separate width for each can simplify stock management, but it increases waste for smaller products. Share your product list and dimensions, and we can determine the width together based on this balance.
How do you choose the thickness?
Choose the thickness according to the group’s weight, the sharpness of its corners and the handling conditions. The general pattern on our product pages is as follows: thinner film for light boxes and cosmetics, medium thickness for canned goods and medium-weight groups, and thicker film for heavy groups such as six-packs of water and beverage bottles, as well as furniture. This is a starting point; test for punctures and tears with the actual product.
We produce shrink film in thicknesses from 20–200 microns, as required. Thicker film is more resistant to impact and punctures, but may take longer to shrink at the same heat. Thickness should therefore be selected with the heating equipment in mind.
Matching the film to the heating equipment
A heat gun may be sufficient for small quantities. Regular production uses a sleeve sealer or shrink tunnel. Include the following information when requesting a quote:
- Whether you apply heat with a heat gun or a tunnel; if using a tunnel, its internal width and height.
- If sealing, the machine’s sealing length.
- The number of groups packed per hour or per day.
- Whether the product is heat-sensitive (label, surface coating, contents).
Common problems
| Appearance | Possible cause | Check |
|---|---|---|
| Wrinkles and pointed ends at the corners | Excess allowance, uneven heat | Try reducing the width and check heat distribution |
| Film remains loose | Insufficient heat or excess allowance | Tunnel speed and temperature, width |
| Film tears or develops holes | Excessive heat, thin film, sharp edge | Heat setting, thickness, corner |
| Air remains inside and the pack balloons | Air cannot escape | Sealing method and air release |
| Group comes apart during transport | Film is too thin for the group | Thickness and group arrangement |
Follow the machine manufacturer’s instructions for equipment settings. For food products, state in your quote request whether the film will come into direct contact with the food; being a food business does not mean every film is suitable for direct contact.
Checklist before requesting a quote
- Product or group being packed: width, length, height and weight.
- Group arrangement: for example, 2 × 3 bottles or a single panel.
- Preferred format: tube, centre-fold or sheet.
- Heating equipment and sealing machine details.
- Colour preference: clear, white or coloured.
- Estimated number of packs per month.
Mertan Ambalaj produces shrink film to order in Denizli. There is no minimum order quantity; you can trial a new width or thickness with a small test order. The total lead time from order approval to delivery is 2–7 days. See delivery options by location.
Send your group dimensions using the quote form. You can also compare the different formats on the shrink film products page.