How It Works

We build shrink packing machines for all products below. What is your product or industry?

Home Care
Liquid Dairy

Shrink Wrapping, Shrink Packaging or Bundle Wrapping is a packaging process in where a group of products is wrapped in shrinkable plastic film which, after exposing to hot air, holds the products firmly together for transport, as a sales unit or for ease of inventory management.

Advantages of shrink wrapping:

  • Low cost, water resistant, less scuffing of labels.
  • Easier and much cheaper to Automate in comparison to tray or case packing.
  • Product is visible, Can be seen through the film (unlike cardboard)
  • Leaking mostly contained to single pack, not damaging full pallet.

Our website is designed to help you decide if and what shrink packaging process and machine is right for your product and environment. However, one has to be aware that not all products can be transported and handled by machine and not all products can be shrink wrapped. Contact Autopack and use our experience to quickly find a competitive solution for your needs.

Shrink packaging like any packaging process involves: Preparation of wrapping material (film),Preparation of product,Enclosing (wrapping) in a sleeve of LDPE film then Shrinking / cooling and discharge.

Each part of the process including the product itself can effect the speed, versatility and quality resultant pack. However, the two main factors are: product collation and wrapping system.

Shrink film

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 can be made with correct shrink ratio for Sleeve Wrapping. (70/20)

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), In slower machines the product is fed single lane and grouping is done inside machine by successive strokes of pneumatic or electric pusher (or lifter.) In faster machines the product is introduced in multilane or pre-collated outside of machine. while high speed machines use continuous motion grouping   
  2. Bundle forming
    A sheet of shrink film is wrapped around the products forming a bundle. there are currently two main ways for wrapping the product,
    - using two rolls with hot knife cutting and sealing
    - using single roll with cold knife cutting and overlap sealing in tunnel
  3. Heat shrinking
    The bundle passes through a heated zone of the shrink tunnel, where re-circulated hot air causes the film to shrink and conform the the shape of enclosed products. Once outside, the pack is cooled by forced air to tighten the film forming semi rigid pack ready for stacking on pallet or further downstream packaging.

Weld Bar Sealing vs Overlap Sealing

There are two ways of wrapping the shrink film around the products.

Weld Bar Sealing
This is the traditional way or Sleeve Wrapping using two, top and bottom film rolls. The two are joined to form a film curtain. When product is ready, it is pushed through, Welding Bar (Sealing Bar) comes down to form a sleeve on the collation of product at the same time cutting the film and rejoining the curtain for the subsequent pack.

Overlap Seal
This process uses single film roll, where a pre-cut sheet of film is wrapped around the product, with the loose ends overlapping beneath the pack. The overlapped region is partially fused in the shrink tunnel at the same time as rest of the sleeve is shrunk to enclose the contents.

The main advantage of Weld Bar type machines is lower cost and smaller footprint.

The main advantage of Overlap machines is higher throughput, better suited for printed film, they tend to be longer and more expensive.

Pads and trays

For additional pack strength or ease of handling, a cardboard pad or tray can be introduced under the product before being shrink wrapped.