While it is common to see the term VFFS, what is really being discussed is a vertical form fill seal machine. This is a specialized packing machine that is used in a wide range of industries to create variable sized bags for items from delicate food items to bagging large and heavy items.
The vertical form fill seal machine is a complex system where each component has a specific place in the process. The machine has to be calibrated correctly to create the right bag size, deposit the perfect weight or amount of material and then seal the bag all in one streamlined process.
Making Bags
With all VFFS machines the bags are not pre-formed or partially formed, rather each bag is made “on demand” from a film. This film can be food grade or standard grade depending on the products.
The film is stored on a roll at the beginning of the machine. The film is pulled through the systems and forms a tube. The bottom of this tube is sealed using heat and pressure methods, then the pre-set amount of product is dropped into the bag. At this point, the same process is used to heat, press and seal the top of the bag. This produces a bag with a seam down the back and a top and bottom seam.
The Seal
One of the most important functions of the vertical form fill seal machine is to create a durable, reliable seal. This is done by both pressure and heating. The amount of pressure and heat is determined by the type of film used to create the bag.
Too much heat results in a melting and fusing of the bag, creating possible holes and irregular seams. Too little heat or not enough pressure creates only a partial seal. This will allow moisture, air, and contaminants into the packaging or result in seams that simply don’t hold.
