What Is Flow Wrap Packaging?

Flow wrap packaging — also called flow wrapping, flowpack, or fin-seal wrapping — is a high-speed packaging process that forms a continuous tube of film around products, seals the tube longitudinally along the product's underside (the fin seal or lap seal), and cuts individual packs with transverse end seals. The result is the ubiquitous pillow pack format seen on chocolate bars, cereal bars, biscuits, bakery items, fresh produce, and thousands of other consumer products.

Flow wrapping machines are divided into two primary configurations: Horizontal Flow Wrap (HFFS) — where products travel horizontally on a conveyor into the wrapping zone — and Vertical Flow Wrap (VFFS) — where film forms a vertical tube and products are dropped in from above. HFFS is preferred for solid, pre-formed products; VFFS for flowable products (chips, coffee, frozen vegetables, liquids in sachets).

Flow wrapping offers exceptional throughput — modern HFFS machines achieve 200–1,500 packs per minute — combined with low film cost per pack, minimal waste, and compatibility with almost every flexible film structure on the market.

HFFS vs. VFFS: Choosing the Right Configuration

Horizontal Form Fill Seal (HFFS)

In HFFS flow wrapping, a flat film reel unwinds horizontally, is formed into a tube around the product using a forming collar and a longitudinal seal, then transverse jaws cut and seal individual packs. HFFS handles discrete solid items — bars, blocks, trays, medical devices, hardware — with excellent pack geometry and minimal product deformation. It is the dominant configuration in confectionery, bakery, snack bars, cheese, and manufactured goods packaging.

Key HFFS features: servo-driven axes for precise timing, integrated vision inspection for seal quality and label registration, quick-change tooling for pack format changeovers, and optional MAP gas flushing (see our MAP guide) for extended shelf life.

Vertical Form Fill Seal (VFFS)

VFFS forms a film tube vertically around a central fill tube, seals the bottom, drops product from above, then seals and cuts the top. VFFS is suited to bulk-weight products — snack chips, coffee, rice, frozen food, pet food, nuts, and liquids/pastes in pouches. The vertical orientation allows gravity-assisted filling and integration with weighers, auger fillers, and liquid dosing systems. VFFS lines regularly achieve 100–200 packs per minute for solid products and higher for liquids.

Flow Wrap Film Structures

Film selection for flow wrapping depends on the product's moisture, oxygen, and light sensitivity, required shelf life, sealing requirements, and sustainability targets:

• OPP/PE (Biaxially Oriented PP / Polyethylene): The most common food flow wrap structure — excellent clarity, good moisture barrier, heat-sealable PE layer, cost-effective. Used for biscuits, confectionery, and dry bakery.
• Metallised OPP: Adds an aluminium metallisation layer for superior oxygen and light barrier. Used for crisps, nuts, and moisture-sensitive snacks. The metallic appearance is also a common aesthetic choice.
• PA/PE (Nylon/Polyethylene): Excellent puncture resistance for sharp, irregular products and good oxygen barrier. Used for processed cheese, fresh pasta, and meat portions.
• EVOH laminates: High gas barrier for extended shelf life applications; commonly used with MAP gas flushing for fresh food.
• Paper-based flow wrap: Paper/PE or paper/metallised structures for sustainable packaging applications — gaining traction in premium confectionery and natural food brands.

Seal Quality and Pack Integrity

Flow wrap pack integrity depends on consistent seal quality across the fin seal (longitudinal) and end seals (transverse). Common seal quality issues include:

• Leaking end seals: Caused by contamination in the seal zone (product particles, oil), incorrect jaw temperature or pressure, or film tracking errors
• Fin seal voids: Result from film tension inconsistency or adhesive/hot-tack performance variation across the film reel
• Dog ears: Incompletely folded film tails at pack ends — typically a forming collar adjustment or film tension issue

Modern flow wrappers integrate 100% vision inspection systems and seal force monitoring to detect and reject defective packs at line speed. For MAP flow wrap applications, headspace gas analysis systems check residual O₂ on every pack.