Roll Stock

Roll stock is flexible packaging film supplied in roll form for use on form-fill-seal (FFS) machinery — where the packaging line itself forms the package from the film, fills it with product and seals it in a continuous automated operation. Rather than buying finished bags or pouches that are then filled on a separate machine, roll stock customers receive printed and laminated film that is converted into the finished package at the point of filling.

For operations running at meaningful production volumes, roll stock is almost always more cost-efficient than pre-made bags. The film is cheaper to produce than a finished pouch, it is more compact to transport and store, and the form-fill-seal process is faster and more consistent than filling pre-made bags on most product types. The trade-off is the capital investment in the filling machine — but for any operation filling more than a modest volume per week, the economics of roll stock versus pre-made bags stack up clearly in favour of roll stock.

At NytronPackaging, we produce roll stock in a wide range of laminated film structures, print specifications, widths and roll formats, all produced to the tolerances required for reliable performance on the specific filling and sealing equipment our customers operate.

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Vertical Form-Fill-Seal Roll Stock

Vertical form-fill-seal (VFFS) is the most widely used FFS format in the food industry. The film unwinds vertically, is pulled over a forming tube that shapes it into a cylinder, sealed along the back edge to form a tube, filled with product dropped or pumped in from above, and sealed across the top and bottom to complete the package. Pillow pouches, four-side seal flat pouches and many other package formats are produced on VFFS machines.

VFFS roll stock is produced to the width required by the specific machine it will run on — the roll width is determined by the circumference of the forming tube plus the back seal overlap, and any deviation from the specified width will cause the machine to run poorly or not at all. We produce VFFS roll stock to tight width tolerances and confirm the correct specification with the customer before production begins. We can also advise on the forming tube size required to produce a given pouch width and gusset depth if you are setting up a new line or changing pack format.

Horizontal Form-Fill-Seal Roll Stock

Horizontal form-fill-seal (HFFS) machines are used for solid or semi-solid products that need to be placed into the package rather than dropped or pumped. The film travels horizontally through the machine, is formed around the product — a biscuit bar, a cheese portion, a confectionery product, a medical device — and sealed on three or four sides to complete the flow wrap package.

HFFS roll stock — commonly called flow wrap film — is produced to the web width required for the specific machine and product dimensions being run. The film must be stiffer and more dimensionally stable than VFFS roll stock because it needs to track accurately through the forming box and the sealing station at high speed without wandering or creasing. We produce HFFS roll stock in structures that balance the stiffness, sealability and barrier properties required for each specific application and machine.

Film Structures for Roll Stock

The film structure for roll stock is specified based on the product being packed, the barrier requirements, the filling conditions, the sealing equipment on the line and any sustainability requirements. The same range of laminated film structures used for pre-made pouches and bags is available in roll stock format — the difference is in the dimensional specification of the roll rather than the film construction itself.

For dry foods — snacks, biscuits, cereals, confectionery, noodles — BOPP/CPP and BOPP/PE structures provide the moisture barrier, stiffness and heat seal performance needed for reliable VFFS operation. For products requiring higher oxygen barrier — coffee, nuts, dried meat snacks, premium food ingredients — structures incorporating metallised film, EVOH or aluminium foil are specified. For frozen food applications, PE-based sealant structures are used that retain their properties at sub-zero temperatures. For pharmaceutical, nutraceutical and high-value ingredient applications, foil-containing structures provide the complete barrier to oxygen, moisture and light that these products require.

Print Registration and Repeat Length

On a form-fill-seal line, the machine uses registration marks printed on the film to position the seal exactly at the correct point in the print repeat — ensuring that the top seal of every package falls at the same position in the design, the product name is centred on the front panel, and no printed elements are cut off by the sealing jaws. This means that the print repeat length on the film must be set precisely to match the package length on the filling machine, and the registration marks must be printed in exactly the correct position and to the correct specification for the machine’s eye mark reader.

We confirm the print repeat length, registration mark specification and roll format with every roll stock customer before production begins. If you are switching from a different film supplier, we will ask for the existing film specification or a sample roll to confirm that our production matches the requirements of your filling line. Getting the registration specification wrong means the film will not run correctly on the machine — it is one of the most common and most avoidable problems in roll stock supply, and we take care to eliminate it at the specification stage.

Roll Format and Core Specification

Roll stock is wound onto cardboard cores and supplied in rolls of a specified diameter and weight that must be compatible with the unwind system and roll handling equipment on the filling machine. Most VFFS machines have a maximum roll weight and diameter determined by the unwind stand, and supplying rolls that exceed those limits causes handling problems and machine downtime.

We produce roll stock in whatever core diameter, roll diameter and roll weight your machine requires. Standard core diameters are 76mm and 152mm (three inch and six inch), and maximum roll weights and diameters are agreed with each customer based on their machine specification. For customers operating multiple machines with different unwind specifications, we can produce rolls in different formats from the same production run.

Splicing and Jointing

On high-speed filling lines, changing a roll of film mid-production causes a line stop that costs time and money. To minimise the frequency of roll changes, rolls are produced to the maximum weight and diameter the machine can handle, and — where the machine is equipped for it — rolls can be spliced together on the unwind stand so that a fresh roll feeds automatically when the running roll is nearly exhausted, without stopping the line.

We produce rolls with a clean, flagged tail end that facilitates accurate manual splicing, and we can discuss flying splice tape application for customers whose unwind equipment supports automatic splicing. Consistent tail end preparation on every roll is one of the details that makes a meaningful difference to line efficiency on high-speed operations.

Quality Control for Roll Stock

Every roll of film we produce goes through a slitting and inspection process before despatch. The film is checked for print quality, registration accuracy, lamination bond strength, seal performance and dimensional accuracy — width, thickness and roll geometry — and any roll that does not meet the agreed specification is not released. We retain a sample from every production batch, and production documentation including material traceability records and test results is available on request.

Consistent quality from roll to roll is arguably more important in roll stock than in any other flexible packaging format, because variation between rolls shows up immediately as line stoppages, seal failures or registration drift on the filling machine. Our quality control process is designed to eliminate that variation before the film leaves our facility.

Working With Us

If you are sourcing roll stock for the first time, switching suppliers, or reviewing your current specification for performance, cost or sustainability reasons, we are straightforward to work with. We will need your machine make and model, your current film specification or a sample roll, your pack size and your volume requirement — and from that information we can produce an accurate specification and a competitive quotation.