LDPE pouches and milk pouch film

Pouch specifications

Running an FFS machine? Send us your machine make and current film spec. Gauge variation is what jams formers and burns seals, so we hold tighter tolerance on FFS rolls. More on that in quality and specs.

How an LDPE pouch is actually made

A pouch starts as blown LDPE film. Granules melt in the extruder, the melt is blown into a bubble, cooled, collapsed and wound onto a roll. That roll then goes to the pouch machine, where the film is folded, sealed on three sides with a heated jaw and cut to length. Everything that goes wrong with a pouch traces back to one of two things: the film gauge wandering, or the seal running too hot or too cold.

Gauge is why we care about the extrusion stage more than the sealing stage. If the film is 55 micron in one place and 48 in another, the seal jaw is set for one and wrong for the other, and you get leakers in a batch that passed a spot check. Consistent thickness across the web is what makes a pouch line run without operator babysitting. The manufacturing page walks through the whole line.

For pouch film on rolls we hold tighter gauge tolerance than for cut bags, because your form-fill-seal machine has no operator to compensate. Tell us the machine make, the roll width, the core diameter and the current gauge, and we will match it rather than send you something close.

Choosing between three-side seal, centre seal and roll film

A three-side-seal pouch is sealed on the two sides and the bottom, open at the top: you fill it and seal or clip the mouth yourself. It is the right choice for hand-packed spares, garment folds, spice packs and sample kits, and it is the cheapest per piece at low volume because no machine investment is needed.

A centre-seal pouch carries a back seam and is used where the pack needs a flatter face for print, typically snack and powder packs. Roll film is for anyone running an automated FFS line: the machine forms, fills and seals in one pass, which is why dairies buy 50 to 60 micron milk pouch film by the roll rather than buying finished pouches at all.

If you are not sure which one you need, describe what goes inside, how it will be filled, and how many units a month. Volume usually decides it: above roughly 50,000 units a month, roll film on a machine beats hand-filled pouches on total cost, even after the machine. Related reading: LDPE film on rolls, LDPE vs LLDPE for why pouch film is usually a blend, and food-grade LDPE for the material side.

LDPE pouch questions