Blown film is created by blowing air through molten plastic to create a huge ‘balloon’. As the balloon cools it creates a film that is then converted into rolls. The thickness of the film can be controlled during manufacture by regulating the quantity of plastic injected and the flow rate of the air. The picture below illustrates this process in action:

Cast film, is created by injecting melted polymer (i.e. plastic) horizontally through a flat die to create a sheet of material, which is then pinned to a chilled roller by an air curtain or vacuum. Further rollers are used to cool the film, before it is trimmed and loaded onto rolls. The latest cast films are created using multiple layers of plastic, all with slightly different properties, which combine to optimise the performance of the film. Best-in-class films multi-layer cast films provide a very high holding force, great puncture resistance and excellent optical clarity. Despite their many layers these film are still ultra-thin, and can be as little as 10mu thick (that’s 10/1000 of a mm…) even before they are stretched. The latest generation of cast films are created using Nano technology and are sometimes referred to as nano films.

The turntable pallet wrappers are the most common variety, pallets are loaded onto a turntable which spins around whilst the film head moves up and down, wrapping the pallet as it does so. These machines are very versatile and can be used in most situations where pallets are loaded using forklift trucks, LLOPS and pumped pallet trucks. The disadvantage is that to a greater or lesser degree, the machines have a turntable base that requires a ramp to enable access, or requires extensive civil works to sink it into the warehouse floor and due to this there are a few situations where a rotary arm or robot machine can be a preferred option. Turntable machines are available in both Core Brake and Power Pre stretch options.

Rotary arm pallet wrappers use a rotating arm that circles the pallet whilst carrying the machine film head with it, the pallet stand still, whilst the head wraps by circling the pallet. The key advantage with these machines are that there is no ramp or incline that the pallet needs to travel up, and also the machines tend to have a smaller footprint – making them an attractive option where space is very tight. Rotary arm machines are available in both Core Brake and Power Pre stretch options.

Robot wrappers are highly mobile pallet wrappers that can be taken to the pallet and will wrap in the same way as a human would wrap a pallet. They are particularly useful where pallets need to be wrapped in a variety of locations, or where stacked pallets are too unstable to move before being wrapped, or where pallets are oversized or unusually shaped as the machine follows the size of the base of the pallet. Robot wrappers are becoming increasingly popular due to their versatility. They are typically a little slower than a turntable wrapper and are mainly manufactured as Power Pre stretch machines.

Inline machines pallet wrapping machines are designed for use in a fully automated production line, and usually sit at the end of the line as the final process in the automation before the product is shipped. Inline machines can be Turntable, Rotary Arm, or Ring wrappers, the choice being made according to the budget and the speed required. Click this link to see a video of a fully inline machine in action.