PFM sealing systems
Rotary, Long Dwell, Box Motion: the right sealing technology for every film, product and line speed
Horizontal flow wrap sealing systems
Every flow pack starts from a single reel of film that wraps around the product and is closed with three seals: one longitudinal seal along the back, and two transverse seals at the ends. It is these two end seals that determine the pack’s performance: its tightness, the speed the line can reach, and the films that can be used.
This is why PFM does not offer a single sealing system, but three families: rotary, Long Dwell / Box Motion and special applications, identifying the most suitable solution for each customer based on three practical criteria: the required line speed, the film type and the product characteristics.
Each sealing shaft can also be configured with 1 to 4 jaws, optimizing the sealing configuration according to pack length, required speed and the flexibility needed to handle different formats.
Horizontal Rotary end seal
High-speed continuous motion
It is the fastest system: the rotary crimp jaws meet on the film as it advances, without ever stopping it. The contact is brief, but sufficient when running standard heat-sealable films and regular, uniform products.
In sectors where speed and consistency matter most, snacks, bakery, confectionery, non-food, rotary sealing is in most cases the most efficient choice: repeatable, uniform seals at maximum throughput.
Horizontal Long Dwell sealing
Extended dwell time for hermetic seals
Some materials require more than a brief contact: high-barrier films, multilayer laminates, recyclable mono-materials and paper-based films need additional time to absorb heat and deliver a reliable seal.
Long Dwell, PFM’s patented transverse sealing system, meets this need without forcing a compromise between speed and quality: the jaws travel with the film and extend the contact time while the line maintains its speed. The result is a genuinely hermetic seal, the fundamental requirement of Modified Atmosphere Packaging (MAP): the pack retains its protective gas mix and extends the shelf life of fresh and chilled products.
Horizontal Box Motion sealing
Extended sealing time and even pressure with zero mechanical stress
Box Motion further extends the effective sealing time compared to Long Dwell: the jaws trace a box-shaped path, they close on the film, move forward with the product for the entire sealing cycle, then open and return to position.
Because the jaws follow the product throughout the sealing cycle, the system makes it possible to pack bulkier, irregular or height-variable products, maintaining prolonged, even pressure and reducing mechanical stress on the pack: strong hermetic seals even on barrier films and MAP formats, with full product integrity at the end of the line.
Special applications
Functional packaging and distinctive formats
Not every requirement is met by a standard pillow pack. When the pack must offer additional functionality, opening and reclosing with a zip, folded hem or label, standing out on the shelf with structured formats, meeting the hygiene requirements of dairy and fresh food, PFM develops dedicated sealing systems.
In these applications the pack becomes an integral part of the product: it improves everyday use and strengthens shelf recognition.
Vertical VFFS sealing systems
In a vertical form-fill-seal machine the entire process takes place in a single cycle: the film travels down the forming tube taking the shape of the bag, the product is loaded from above and the seals close the pack. The two transverse seals perform a double function: the same seal that closes one bag already forms the bottom of the next.
It is the most efficient solution for packing loose, granular and powdered products. The choice of sealing system depends on the nature of the product, granular, powder, fragile or liquid, the desired bag format and the required output.
Verical Intermittent motion sealing
Precision and control with the film at rest
The film advances in steps and sealing takes place while the film is stationary: the jaws have all the contact time they need, and every seal is controlled and precise.
It is the most suitable choice when precision prevails over raw speed: auger-dosed powders, accurate portioning, complex formats such as block bottom, Steelo Bag and doy-style, and production runs with frequent format changes.
Vertical Continuous motion sealing
Maximum output for pillow pack bags without stopping the film
When the goal is maximum output, the film never stops: the jaws seal in its advancement with rotary motion, with no pauses and no dead time.
It is the configuration of high-volume production (snacks, crisps, confectionery, pasta…) where the bagger operates in line with MBP multihead weighers and volumetric or auger dosing systems.
Vertical Long Dwell and Box Motion sealing
Hermetic performance even at high speed
In vertical packaging too, the most demanding films require longer contact time. PFM’s patented Long Dwell rotary head provides it without giving up continuous motion, ensuring airtight seals on barrier films, recyclable mono-materials and paper-based films, including MAP applications.
For structured bags, block bottom, Steelo Bag, doy-style, the box-motion unit applies prolonged, even pressure while following the film’s travel: strong seals and well-defined corners that ensure the bag stands perfectly on the shelf.
FAQ – Frequently Asked Questions
What is the difference between rotary and Long Dwell sealing?
Rotary sealing prioritizes speed: the jaws rotate continuously and film contact is brief, sufficient for standard heat-sealable films. Long Dwell extends that contact without stopping the line: it is this additional time that makes hermetic seals possible on barrier films, multilayer laminates and harder-to-seal recyclable materials.
When is Box Motion sealing needed?
When the product is bulky, fragile, irregular or variable in height: Box Motion further extends the effective sealing time compared to Long Dwell, and the jaws follow the product throughout the cycle, applying prolonged, even pressure with no mechanical stress on the pack.
Which sealing system suits Modified Atmosphere Packaging (MAP)?
Long Dwell and Box Motion: the extended contact time delivers the hermetic seal needed to preserve the protective gas mix and extend the shelf life of fresh and chilled products.
What is the difference between intermittent and continuous motion VFFS?
In intermittent motion the film stops during sealing: maximum contact time and maximum precision, ideal for various types of product but especially for flat-bottom, doy-style, or pillow-bag packs up to 80-120 depending on pack length. In continuous motion the jaws seal the moving film: maximum output for granular products and snacks.
Can PFM machines seal recyclable and paper-based films?
Yes. Extended-contact sealing systems are also designed for recyclable mono-materials (PE/PP) and paper-based films, which require more time than traditional laminates to absorb heat and seal reliably.
