The film is not a mere accessory of the vertical packaging machine. It is a technical variable that affects feeding, sealing, bag shape, product protection, stability, and production continuity.
An inappropriate choice can lead to waste, production stoppages, cosmetic defects, size instability, or sealing issues. That is why VAI the film in conjunction with the product, the machine, the size, and the production line’s objectives.
A film should be chosen based on the process, not just the product
When selecting film for vertical form-fill-seal machines, it is important to consider the product, format, barrier requirements, stiffness, flowability, and sealing parameters. An incorrect choice can lead to increased scrap, bag instability, and line stoppages. Pre-testing with the actual product helps validate the material before production begins.
The same product may require different films depending on its size, weight, line speed, and the type of bag desired. A film suitable for a small size is not always appropriate for a larger bag or for a product that tends to distort the packaging.
The selection must also take into account the film’s behavior on the machine: passage over the forming tube, tension, centering, sealing, response to temperature changes, and interaction with the product during filling.
For this reason, in VAI vertical packaging machines, the film is treated as part of the process. The machine must be able to process the material continuously and produce a stable, legible bag that is suitable for its intended use.
Product, format, and barrier: the first variables to evaluate
The first question concerns the product. Powders, granules, grains, dried fruit, legumes, snacks, and technical materials do not all require the same type of protection. Some products are sensitive to moisture, others to oxygen, and still others primarily require mechanical strength and dimensional stability.
The second factor is the size. A large bag requires a film capable of maintaining its shape and integrity even under weight. A small bag may require greater precision in sealing and control over the final appearance. A bag intended for palletizing must maintain uniform proportions even after handling and transport.
The variables that need to be clarified are:
- required barrier against moisture, light, oxygen, or external contaminants;
- rigidity of the material, which helps maintain the shape;
- elasticity, which must be checked to prevent deformation;
- thickness, which affects strength and machining behavior;
- weldability, which is crucial for leak-tightness and continuous production.
The decision cannot be made based solely on the film's technical specifications. It must be evaluated based on the actual combination of product, weight, format, and production pace.
Multilayer Films, Single-Material Films, and Behavior in Machinery
Multilayer (laminated) films can offer different levels of performance in terms of barrier properties, strength, and sealability. Single-material films may be considered when the project requires specific technical specifications for the material—both in terms of aesthetic appeal and material cost—but they must still be compatible with the machine, product, and format.
For VAI , the key is VAI to choose a film family in an abstract way. It is to verify whether that material performs well on the line: whether it feeds smoothly, stays centered, fits the forming tube, responds well to the sealing bars, and retains the bag’s shape after filling.
Film that is too stiff can cause tension. Film that is too flexible can cause deformation. Film with inconsistent weldability can result in scrap, micro-leaks, or recurring defects.
For this reason, the choice of film must be integrated into the design of industrial packaging solutions, especially when the product exhibits variable behavior or its format affects logistics.
Why Test the Film Before Production
Pre-testing allows us to verify what the technical data sheet does not always show clearly enough: performance in the machine, yield on the actual format, weld stability, response to filling, and the integrity of the finished bag.
During the test, it is possible to observe whether the film moves correctly on the forming tube, whether it maintains a consistent tension, whether the seal is stable, and whether the bag retains its intended shape after filling.
An effective audit should include:
- a live-action film scheduled for production;
- the customer's actual product;
- final target weight;
- bag size to be validated;
- a speed consistent with the production target;
- Checking the shape of the bag after handling.
How do you choose the film for a VFFS machine?
The selection is based on an evaluation of the product, format, barrier properties, stiffness, thickness, sealability, and performance on the machine. Testing with the actual product helps reduce risks and waste.
When is a barrier film needed?
It is used when the product needs to be protected from oxygen, moisture, or other external factors that could affect its quality, stability, or shelf life.
Why conduct a test using actual film?
Because the film must be tested on the machine using the actual product and format. This is the only way to verify the bag's performance under conditions that closely resemble actual production.
To test the results with your actual material, you can contact the VAI team and evaluate the film, product, format, and machine settings before production.
Where these aspects are reflected in the configuration
The choice of film and the welding parameters are determined based on the machine and the format. The areas we most frequently focus on in this regard are:
- V5/10 — VFFS up to 10 kg and 20 liters, with a wide range of options for sizes and materials.
- TFD — automated carousel with hot-bar welding and air cooling.
- MV305 — for vacuum-sealing up to 25 kg.
Industry-Specific Insights: Flour, Sugar, Snacks, and Cookies.
