Flexible pouches have become the default pack for snacks, spices, tea, detergents and many other products. Every one of those pouches needs legible, durable codes such as batch numbers, dates and prices. Coding on film is very different from coding on a rigid bottle or a corrugated box, and choosing the wrong technology leads to smudged prints, rejected packs and wasted film.
The Main Coding Technologies for Film
Three technologies cover most pouch coding applications:
- Thermal transfer overprinting (TTO): a printhead heats a ribbon and transfers ink onto the film. It produces sharp text, logos and even barcodes.
- Continuous inkjet (CIJ): tiny ink droplets are fired at the film. It is non-contact and suits fast-moving or irregular surfaces.
- Hot stamp or roller coders: heated characters press a ribbon onto the film. These are simple, low-cost solutions for basic codes.
When TTO Makes Sense
TTO is ideal for coding flat film on form-fill-seal machines before the pouch is made. Print quality is excellent, codes are durable and there is no wet ink to dry or smudge. TTO can also print variable data like prices and barcodes, making it popular for retail packs. Ribbon is the main consumable, and modern printers use it efficiently by printing only where needed.
When CIJ Makes Sense
CIJ works well when packs are already formed, when the surface is uneven or when speeds are very high. Because it does not touch the pack, it is useful for coding sealed pouches on a conveyor. CIJ ink must be chosen to adhere to your specific film, and the printer needs regular maintenance to keep nozzles clean.
When Hot Stamp Coders Are Enough
For small producers printing a simple batch number and date, a hot stamp or roller coder mounted on a sealing machine is an affordable option. Characters are set manually, so frequent changes are tedious, and print quality is basic. Many businesses start here and upgrade to TTO as volumes and requirements grow.
Film Matters
Different films accept codes differently. Laminates with a printed surface, metallised films and polyethylene all behave differently. Before buying a coder, test it on your actual film. Ask about ink or ribbon options that suit your film, and check how the code survives rubbing, freezing or exposure to oil if relevant.
Positioning the Code
Choose a clear area of the pack, ideally a light-coloured window in the artwork reserved for coding. Dark backgrounds make dark codes unreadable. Coordinate with your design team so the coding area is planned into the artwork from the start.
Integration With Packing Machines
On a form-fill-seal machine, the coder must print in sync with the film movement. Intermittent machines suit TTO in intermittent mode, while continuous-motion machines use TTO in continuous mode or CIJ. Proper mounting brackets and signal connections make integration smooth.
Ribbon and Ink Economy
Consumables are an ongoing cost. Ask suppliers about ribbon-saving modes and ink consumption per thousand codes, and compare these figures alongside the printer price.
Avoiding Common Problems
Faded prints usually mean incorrect printhead pressure or temperature. Smudged codes point to ink compatibility issues. Missing codes may be caused by sensor or signal faults. A simple check at the start of each shift catches most issues.
Hilden supplies coding solutions for flexible packaging and can test codes on your film before installation, ensuring that every pouch leaves the line with a clear, compliant code.
