You know, there are many different kinds heat shrink machines. Different shrink machine will be different working process. Shrink Packaging can be divided into following categories
A) Primary- where the product is totally enclosed for protection from abrasion, dust, moisture and for improved appeal.

B) Secondary- where a group of items is wrapped together to form a Sales unit like cold drink pet bottles of cold drinks, boxes etc

C)Distribution packaging - where product is wrapped into a distribution unit which may stacked directly on the pallet ready for transportation.

When walking through supermarket one only has to look on top of the shelves to see the extent of use of this packaging method.
Most grocery and high volume beverage products will use cardboard trays for added Rigidity of the pack. While the use tray is not always necessary, it does provide improved handling in automated warehouses.

Shrink Packaging Process

Shrink wrapping, bundle wrapping, etc, is a process during which a product item or a group of items in wrapped in a loose sleeve or envelope of plastic film, which upon application of heat shrinks and tightly conforms to the shape of enclosed contents.
The key element of this process is Shrink Film. Shrink Film can be made from a variety of materials each having different strength, shrink characteristics transparency and luster.

If you want to know more details of the heat shrink machines, feel free to contact YUPACK workers.