About Shrink Packaging
Shrink wrapping (or bundle wrapping) is a packaging process where a group of products are wrapped in plastic film which protects them and holds them stongly together, typically as a sales unit.
On this page we will help you decide whether shrink wrapping is the right process for your needs, by comparing it with your other options, and describing the process in more detail. However, if you are unsure what packaging type is appropriate, please contact us; we may be able to suggest innovative solutions that fit your needs.
Alternatives to shrink wrapping
All these forms of packaging, as well as shrink wrapping, can have custom designs printed on the packaging.
- Cardboard cartons/boxes
- One or more products are fully enclosed. The box can be sealed with glue/tape, or with interlocking flaps (like a box of toothpaste).
- Cardboard trays
- The products are placed in a cardboard tray for easier handling.
- Cardboard/plastic crates
- Similar to trays, but since crates are more durable they are typically re-used.
Advantages of shrink wrapping
- Very little raw material used per pack
- Shrink wrapping is much easier (and therefore cheaper) to automate than tray or box forming
- Product can be seen through the film (unlike cardboard)
- Pack shape is curved rather than angular and follows contours of product
Shrink wrapping FAQ
What sorts of products can be shrink wrapped?
Most bottles, cans, cartons and boxes are ideal for shrink wrapping. It is also possible to shrink wrap many other sorts of products. Very lightweight or oddly shaped products can be challenging to shrink wrap, either because they are hard to manoeuvre during the wrapping process, or because the sideward forces imposed by the film cause the pack to become misshapen.
Can the high temperature of the shrink process affect my products?
Due to the short exposure time and protection offered by the shrink film itself, very few products are affected by the process. Even foil-wrapped chocolate can be shrink wrapped.
How many products can fit in a bundle?
It depends on the size and weight of the products. 12 drink cans (4×3) can be securely wrapped. With smaller products, more can be included. Note that we have vertical stacking options to allow multiple layers of cans and boxes
Are the products fully enclosed?
No. Although the film shrinks around the products, there will be a round opening in the film on either side of the pack.
Can I use the same machine for different products?
Certainly! Autopack machines are designed to be rapidly adjustable to a wide range of products. Submit an enquiry if you would like to find the best machine to suit your needs.
Polyethylene (PE) in its low-density form (LDPE) is the best suited plastic film for general shrink wrap packaging. This is because it is relatively strong, inexpensive and has a good shrink ratio.
The shrink wrapping process
The shrink wrapping process consists of 3 steps:
- 1. Product grouping
- The products are arranged into a group (e.g. 3×2 bottles to form a 6-pack)
- 2. Bundle forming
- A sleeve of shrink film is wrapped around the products forming a bundle
- 3. Heat treatment
- The bundle passes through a heated tunnel (known as the shrink tunnel), and the heat causes the film to shrink around the items, pressing them together. The pack is then allowed to cool, and the film stregthens and tightens around the items, making the pack fairly rigid.
Sealing versus Overlap
During the bundle forming stage, there are two ways to wrap a film sleeve around the products.
- The product is pushed through a sheet of film, and then a heated knife (the sealing bar) joins the sheet to itself, forming a sleeve around the product.
- A pre-cut sheet of film is wrapped around the product, with the loose ends overlapping beneath the pack. The loose ends fuse in the shrink tunnel due to the high temperature.
The main advantage of sealing–type machines is lower cost and smaller footprint. The main advantage of overlap–type machines is high throughput.
Pads and trays
For additional pack strength or ease of handling, packs can be placed on a cardboard pad or tray before being shrink wrapped.