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> Home > Our Machines > Bag Filling - Open Mouth Bags > Form Fill Seal or Pre-Made Bags?
Form Fill Seal or Pre Made Bags

What is Form Fill Seal?

  • A fully automatic low cost packing concept for dry solids, pellets, flakes, powders, crystals, fibrous materials and slurries or pastes
  • The bag is Formed on the bagging machine from a roll of film, immediately Filled then Sealed across the top

What types of FFS bagging machines are available?

Vertical FFS - bags made from roll of flat sheet of film

Horizontal FFS - bags made from roll of tubular film

C-Fold FFS - bags made from roll of film with a ‘C’ or ‘U’ fold at bottom

Why is FFS growing?

Because of synthesis of film & packaging machinery developments

  • new stronger, lighter films are less expensive
  • improved film sealing technology and powder handling techniques
  • Printing the film within the FFS machine before the bag is made provides the ability to change product or batch without loading a new roll of film
  • Ease and reliability of automating the bagging operation
  • Reduces the number of operators on the bagging line
  • Improves productivity owing to a dramatic increase of packing rate

Printing film within the FFS machine

What are the advantages of FFS?


  • Bags made on FFS are less expensive than pre-made bags = “pay back”
  • Lower capital cost than fully auto machine when packing rate above 500 bags/h
  • Total automation - usually unattended, labour saving provides = “pay-back”
  • Consistent packing rate
  • Compact (especially the Vertical FFS)
  • Fast - increased production rate, reduced no. of shifts = “pay back”
  • Easy and quick to clean-out between production batches
  • Fewer moving parts - especially Vertical FFS
  • 'Online’ film printing provides readable bar code and product info

What are the disadvantages of FFS? 


  • Not economical for short production runs of one bag size - below 1000 x 25 Kg bags = 25 tons
  • Cannot handle paper
  • Cannot handle multi-ply packing materials
  • Not economical for packing low density, aerated powders such as wheat flour, talcum powder, skimmed and whey powder at medium speeds
  • Cannot remove ‘trapped air’ very quickly or easily
  • Shape of package made by Vertical FFS  or ‘C’ type FFS not as good as valve sack
  • Cannot self adjust for different widths of bag (but changing length is very easy on Horizontal and Vertical FFS machines)

What factors should be considered when contemplating FFS?

  • Will your customers accept plastic bags?
  • Are plastic bags tough enough?
  • Do any regulations prohibit the use of plastic bags?
  • Speed – is bagging rate above 200-300 bags/hour
  • Can you run one bag size and weight continuously for a minimum of 2 hours
  • Are your products:- fine, aerated, low density, if so FFS may be expensive especially if you pack 3 x 25kg bags/minute

Trapped Air 

  • Problem for both FFS and also filling machines for open mouth, pre-made bag
  • Air is always left in the bag between the level of the product and the sealed top of the bags – in the “ullage” space.
  • Cannot easily be removed 100% before sealing
  • Solutions when filling pre-made bags:
  • Squeeze top of the bag - not 100% effective
  • Exhaust through porous bags material - effective when filling valve sacks
  • Multi wall bag - air escapes through labyrinth of perforations
  • Exhaust through sewing
  • Bags made from perforated plastic

Removing trapped air when bagging with FFS

De-aerating powders during filling

Pre-settling of powders in surge hopper above filling machine
Filling the bag from the “bottom-up”
De-aeration probe in tube sucks out air or powder in forming tube or bag
Vibration of bag during filling low/high frequency to suit nature of powder

Removing trapped air from ullage space

Squeeze the air out through perforation - essential when bagging over 360 bags/h, filled bag is conveyed through bag flattener
Perforated overlap seal provides labyrinth for passage of air
Use suction pipes in forming tube to suck out trapped air as the top of the bag is closed, then sealed
One wag valve on film or bag = expensive
Other patented techniques