Technology Reference / Primary Packaging & Filling / Flow-Wrapping (Horizontal FFS)
Primary Packaging & Filling

Flow-Wrapping (Horizontal FFS)

Wrapping a discrete solid in a single web of film into a sealed pillow pack — the high-speed standard for individually wrapping bars, units, and trays. At speed, one cold seal jaw can open hundreds of packs before anyone notices.

This page’s family — the operations that put a product into its primary container and seal it, which is where flow-wrapping lives.See the other primary packaging & filling technologies The discrete solids the wrapper wraps — bars, tablets, units — are formed and finished upstream in the encapsulation and solid-dose family.See the encapsulation & solid dose technologies Once individually wrapped, the units are coded, cartoned, cased, and shipped downstream in the labeling and secondary packaging family.See the labeling, secondary packaging & logistics technologies
What it is

One web of film, wrapped around a solid, sealed on three sides.

Flow-wrapping is a horizontal form-fill-seal technology that wraps a solid product in a single web of film, forming a sealed pillow pack with a longitudinal fin or lap seal and two end (crimp) seals. It’s the high-speed standard for wrapping discrete solid items — bars, sticks, single units, trays — protecting them and carrying graphics.

Where vertical FFS drops a flowable into a formed bag, flow-wrap is built for things with a shape: it wraps what’s fed to it, at very high speed, and the seals are formed around the product as it moves.

The levers are seal-jaw temperature and pressure, the film and sealant, registration (for printed film), speed, and product feeding. Two of them dominate: the seal jaws that close every pack, and the infeed timing that keeps product out of the crimp.

Product is fed on a horizontal conveyor into a former, film is wrapped around it with a longitudinal fin or lap seal, end seals close and cut each unit between products, and packs are coded with rejects for missing product or bad seals.

Process flow
1

Product fed on a horizontal conveyor into a forming box or former

2

Film wrapped around it; longitudinal fin or lap seal made

3

End (crimp) seals close and cut each unit between products

4

Coded; rejects for missing/short product or bad seals

Individually flow-wrapped solid units

The leversSeal-jaw temperature and pressure, film and sealant, registration (for printed film), speed, and product feeding.
Why it matters

Protect and present a solid unit — at a speed that hides failures.

Flow-wrap is about protecting and presenting a solid unit at very high speed, so seal integrity (fin and end seals) and barrier set the shelf life and protection, while print registration sets shelf appearance. The format earns its place on throughput — which is exactly why its failures multiply quietly.

At speed, an under-temperature jaw or a product caught in the crimp produces open seals and exposed product across many units before anyone notices without inline checks. The discipline is inline monitoring of fin and crimp seal integrity, infeed timing controls against product-in-seal events, a film barrier matched to shelf life, print-registration control on graphic film, verified coding legibility, and film/sealant substitutions requalified for sealing and barrier.

21 CFR 174–178 · food-contactThe film and sealant that touch the product have to be cleared for that contact under the FDA indirect food-additive rules.
21 CFR 211.94 · container-closureWhen the wrap is a drug’s container-closure, it has to protect the unit and stay non-reactive, non-additive, and non-absorptive with it.
USP <661> · packagingSets how the plastic packaging material is identified and tested for the properties that matter to the packaged product.
ASTM F88 · seal strengthThe heat-seal strength test that measures the force it takes to peel a fin or end seal apart, so you can show the seals hold at line speed instead of springing open.

Food-contact film under 21 CFR 174–178; drug container-closure under 211.94 + USP <661>; ASTM F88 seal-strength testing anchors the rest.

How it compares

Why a maker flow-wraps — and what they trade.

Flow-wrap is the fast, cheap way to individually wrap a solid. Knowing what it was chosen over tells you what the product needed.

vs.

Vertical FFS

VFFS handles flowable powders and liquids dropping into a formed bag.

The tradeFlow-wrap handles discrete solids fed horizontally — a different feed, a different machine.
vs.

Tray + lidding / shrink-wrap

Trays suit fragile or multi-count products.

The tradeFlow-wrap suits single sturdy items at speed, without the tray cost.
vs.

Cartoning

A carton gives rigidity and a shelf face.

The tradeFlow-wrap is cheaper and faster for primary protection, with less rigidity.
Where it tends to go wrong

The gaps a reviewer looks for on a flow-wrapper.

None of these are exotic. They’re the quiet places open seals slip through at speed — recognizable the moment you’ve run a flow-wrapper.

Fin and crimp seal integrity isn’t monitored — open seals at speed expose product.

Product is caught in the end-seal from poor infeed timing, causing seal failures.

Film barrier isn’t matched to the product’s shelf-life needs.

Print registration drifts on graphic film — mis-cut, off-register packs.

Coding and date legibility aren’t checked.

Film/sealant substitution without sealing and barrier requalification.

If this is your operation

Six things to check against your own records.

Not an audit — a read you can run yourself before anyone else does. Pull one recent run and walk it.

01

Ask how fin and crimp seal integrity are monitored inline.

02

Check infeed timing controls against product-in-seal events.

03

Confirm the film barrier suits the product’s shelf life.

04

Review print-registration control on graphic film.

05

Look at coding legibility checks.

06

Verify any film change was requalified for seal and barrier.

Applications

The same wrap, across very different solids.

The product changes — the discipline never does: hold the seal jaws, time the infeed, match the barrier.

Supplement

Bars & single units

Protein and nutrition bars flow-wrapped at speed, where the fin and crimp seals carry freshness and the barrier holds shelf life.

Food & beverage

Confectionery & baked goods

Individually wrapped candies, cookies, and snacks, where print registration drives shelf appeal and seal integrity protects.

Pharma / device

Devices & single items

Flow-wrapped devices, wipes, and single units where container-closure and barrier matter to the product inside.

Cosmetic

Soaps & solid units

Bar soaps and solid personal-care units wrapped for protection and presentation in one fast step.