Vertical Form Fill Seal Packaging Machines

The same machine principle produces different bags. A pillow bag is the simplest and fastest; a gusseted bag stands better and holds more volume; block-bottom and quad-seal bags stand upright on the shelf and need the corresponding forming and sealing equipment.

Film is chosen with the film supplier for the product's barrier needs and the seal the machine must make: laminated films such as PET/PE or OPP/CPP, metallised films for light and oxygen barrier, and mono-material films where recyclability matters. Sealing temperatures, jaw pressure and dwell time are set per film.

Bags per minute depend on the bag length, the fill volume, how fast the product falls through the tube, the sealing time the film needs and whether the jaws move intermittently or continuously. Dosing accuracy and speed depend on the weigher or filler and on the product.

DOKTEK therefore states capacity for the agreed product, bag and film in the quotation. The article on calculating packaging machine capacity explains how to work out what a line actually needs.

Bag length, temperatures and dosing targets are stored as recipes on the HMI. A change of bag width means a change of forming set; a change of bag length or target weight is a recipe change.

Food-contact parts are stainless steel or food-grade plastics. The frame is designed for access to the forming set, jaws and dosing outlet, and the cleaning concept — dry clean or wash-down — is defined per product.

Moving jaws and film transport sit behind interlocked guards with emergency stops. CE documentation can be prepared according to the machine scope and the destination market.

Upstream, a VFFS machine is usually fed by a multihead or linear weigher on a platform above it, which is fed by an incline or bucket conveyor from the processing line. Downstream, bags go to a checkweigher, a metal detector and case packing. DOKTEK specifies these hand-overs with the bagger rather than leaving them to the site.