If you buy chips, namkeen, sugar, tea, rice or frozen vegetables in a pouch, there is a good chance it was made on a vertical form-fill-seal machine. These machines are the backbone of flexible packaging because they make the pack, fill it and seal it in one continuous process from a roll of film. For small and growing food companies, a VFFS machine is often the first major packaging investment.
How VFFS Works
The process follows the same sequence for every pouch:
- Film is unwound from a roll and pulled over a forming collar.
- The collar folds the film around a vertical tube, forming a continuous tube of film.
- A vertical sealer seals the overlap or fin seam along the length.
- Horizontal jaws seal the bottom of the pouch.
- The product is dosed through the forming tube into the pouch.
- The jaws seal the top, which also forms the bottom of the next pouch, and cut the pouch free.
Pouch Styles
The most common style is the pillow pouch, with a back seal and top and bottom seals. Gusseted pouches have folded sides that allow the pack to stand or hold more volume. Quad seal and flat bottom styles offer better shelf presence but require more sophisticated machines.
Choosing the Dosing System
VFFS machines are paired with a dosing system that matches the product:
- Multi-head weighers for snacks, frozen foods and irregular items
- Cup fillers for free-flowing granules like sugar and rice
- Auger fillers for powders like spices and flour
- Liquid pumps or piston fillers for liquids and pastes
Intermittent or Continuous Motion
Intermittent machines stop the film while sealing, which gives good seal quality and suits most applications. Continuous-motion machines keep the film moving and use rotating jaws, achieving higher speeds for products like snacks.
Film Considerations
The film must suit the machine and product. Laminated films provide barrier properties for snacks, while polyethylene works for many dry goods. Seal temperature, film thickness and registration marks must match machine settings. Printed film needs an eye mark so the machine cuts each pouch in the correct place.
Nitrogen Flushing for Snacks
Snacks are often packed with nitrogen to protect against oxidation and to cushion the product. VFFS machines can be fitted with a nitrogen flushing system that displaces oxygen in the pouch before sealing.
Common Problems
- Poor seals: adjust temperature, pressure or dwell time and check jaw condition.
- Product in seal area: adjust timing between dosing and sealing.
- Film tracking: check alignment and tension.
- Inconsistent pouch length: check eye mark sensor settings.
Film Splicing and Roll Changes
Each roll change stops production briefly. Larger roll diameters and automatic splicing systems reduce these stops on busy lines. For smaller operations, training operators to change rolls quickly and thread the film correctly every time has a similar effect at no cost. Keep a printed threading diagram at the machine.
Starting Out
A small company might start with a semi-automatic machine or a basic VFFS with a cup filler. As volumes grow, upgrading to multi-head weighers and faster machines is natural.
Hilden supplies pouch packing machines and dosing systems for food products, and can help you select a VFFS setup based on your product, pouch style and production volume.
