Calculating film dimensions to flow wrap your product is one of the most difficult tasks. A slight mistake can either create a big gap or can leave a small part outside the flow wrap. In this article, we will teach how to calculate film dimensions accurately in order to flow wrap your product. Once you have the right dimensions you can easily wrap the product using flow wrapping machine.
Basic Details about Wrappers
Every wrapper has a back stand (film feed assembly), an infeed conveyor, a cutting head, a discharge area, a film-forming area, and a fin seal (bottom seal). All the products (food and non-food) are placed on the infeed conveyor of the flow wrapper by the processing equipment. This can also be done manually by hand feeding.
As the infeed conveyor drop-ship a product to the forming space, the film is drawn from the ‘film feed assembly’ into the forming space, and a movie tube is made around the product and a fin seal is formed. The film tube and therefore the product both are delivered to the cutting head. The cutting head creates the top seals and it cuts the adjacent wrapped product into individual packages, and delivers it to the discharge space.
Types of Film
There are two types of films cold seal film and hot seal film. The type of film to use depends on various reasons including product characteristics, material costs, required capacity/speed, necessary barriers (ultraviolet, oxygen, etc.), hermetic seal strength or integrity.
A base material (carrier) and a skinny layer of glue are the main components of cold seal film. In order to make this sort of film waterproof, it is pressed with two layers of glue together. This is why cold seal films can be used at higher film speeds than heat seal films. Hot seal films area unit is usually multi-layered and includes an outer coating to stop the film from melting. The core of the film includes plastic, and a sealer layer on the inside that has a lower melting temperature and bonds to seal the package along.
Calculating Film Dimensions
The first step to calculating film dimensions is determining the correct cut-off length. This is more important for registered film with graphics that need to be at the center of each package. To determine the amount of film taken by the angle to the seal, divide the product height with 0.86603.
Once you’ve determined the cut-off length, its time to determine the film web width. The 5mm (o.2″) is often explained by the gap (including the peak and thickness of the deck plates) from the merchandise to the fin seal rollers and a few further films to assure sensible chase within the fin seal rollers. Common fin seal roller heights square measure half dozen, nine and fifteen metric linear units along with the 5mm of film for chase functions, this leads to fin seal widths of eleven, fourteen and twenty metric linear units severally.
The above-mentioned formulas are just for calculating the basic film dimensions. For better and accurate film sizing and cut-off, test it on your machine with the actual product and film.