For a production line running on form-fill-seal (FFS) machines, the roll film directly determines line efficiency. The wrong film means breaks, misregistered print, weak seals and unplanned downtime. We have compiled seven parameters to clarify with your supplier before ordering.
1. Film width and reel dimensions
Film width is determined by your machine’s former size and the pack dimensions. In addition, the core inner diameter and maximum reel outer diameter must match your machine’s unwind unit. Confirm these from your machine manual or technical service.
2. Winding direction
Whether the print is on the inside or outside of the reel and in which direction it reads (winding direction) depends on how the machine feeds the film. The wrong winding direction can make the print come out upside down or unusable. Sharing a photo of the reel you currently use largely prevents such mistakes.
3. Eyemark
The machine determines the cut point of each pack by reading the eyemark in the print. The mark’s size, colour, position and contrast with the background must be readable by your sensor. Insufficient contrast causes cutting to drift.
4. Repeat length
The film length needed for one pack determines the design’s repeat length. This value must match your machine’s jaw and pull-down system.
5. Sealing temperature and hot tack
The temperature at which the film’s inner layer starts to seal determines your line speed. On high-speed lines, hot tack strength is critical because the product drops into the bag before the seal has cooled. For products containing powder or particles, inner layers that can seal even through contaminated surfaces should be preferred.
6. Coefficient of friction (COF)
This indicates how easily the film slides over machine parts and over itself. Too high a friction causes the film to snag; too low causes uncontrolled slipping. It should be within the range recommended for your machine.
7. Barrier structure and thickness
How much protection your product needs against moisture, oxygen and light determines the film structure. A dry snack and a high-fat product, for example, do not have the same needs. Thickness affects both mechanical strength and cost; a film thicker than necessary is unnecessary cost.
Pre-order checklist
- Machine brand and model
- Film width and repeat length
- Core inner diameter and maximum outer diameter
- Winding direction (with a photo if possible)
- Eyemark position and colour
- Product type, filling temperature and line speed
- Required shelf life
Porpack’s approach
At Porpack we don’t define roll film structures at a desk, but according to the real journey your product takes from the production line to the shelf. With our multi-layer extrusion and lamination capabilities, we tailor barrier, thickness and print to your line.
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