Granules are free-flowing bulk materials: sugar, salt, rice, grains, granular animal feed, snack granules, and fertilizer pellets. For these products, the vertical form, fill, and seal machine is the standard platform: up to 80 bags per minute with ±1% dosing accuracy, depending on the product and film.
The Structure of the Line
The basis is the vertical form, fill, and seal machine: film roll, forming shoulder, bottom and top seals. Above the machine, a multi-head weigher accurately fill the bag to the specified product weight. For fine granules that are dusty or sticky, a screw feeder is the alternative.
Step-by-Step Guide to the Selection Process
- Test the product: flow, particle size, dust formation, susceptibility to breakage.
- Set the dosing range, from the smallest to the largest bag weight.
- Select the bag size and type: pillow bag, stand-up bag, or block-bottom bag.
- Record output in bags per minute, not in hourly rates on paper.
- Select the film based on its single-material composition and barrier requirements.
| Product | What to Look For | Dosing device |
|---|---|---|
| Sugar and Salt | Fine particles, dust formation | Multihead weigher with cover, or screw feeder |
| Rice and Grains | Prone to breakage | Multihead weigher with a low drop height and a gentle infeed |
| Animal Feed Pellets | Dust and Grease | Multihead weigher, 304 stainless steel product contact |
| Fertilizer pellets | Corrosive | Stainless steel 316 version and corrosion-resistant seal |
Plastic Film and Sustainability
Granules require a dust-tight seal; a 50- to 80-µm PE monolaminate is sufficient for this purpose, as it is recyclable as a single material. When requesting quotes, ask for the film consumption per 1,000 bags—this difference between machines will persist as long as the line is running.
What We've Learned from Experience
- Dust in the seal seam is the classic problem with sugar and salt: the seam doesn't seal, and the bag leaks. Vacuuming at the filling station and a field dosing system solve the problem.
- Rice and grains break during the fall; a low drop height and a gentle feed rate keep breakage to a minimum.
- Hygroscopic granules clump when exposed to moisture; store and transport them in a sealed container to a location just above the machine.
When a VFFS for granules isn't suitable
- Sticky or highly hygroscopic product: the dosing chute becomes clogged and dosing stops.
- Is the doypack If that's your main selling point, then choose a packaging machine for preformed bags.
- Bags weighing approximately 10 kg or more require a heavier-duty frame; discuss the dosing weight with the supplier in advance.
Frequently Asked Questions
Q: Which film should I choose for granules?
PE monolaminate for dry granules, or a barrier-lined film if the product loses moisture or odor. The bottom seal must be dustproof.
Q: How do I prevent dust from getting into the seal?
With extraction at the filling station, field dosing, and a film selection that matches the particle. Check the first bags after each film change.
Q: Can a single machine process both granules and powder?
Yes, by switching the dosing equipment: a multihead weigher for granules and a screw feeder for powder. Check out the powder packaging solution for that track.
Related pages
vertical form, fill, and seal machine | multi-head weigher | sugar packaging machine | rice packaging machine | grain packaging machine
Request a technical proposal Please specify the product, bag size, and desired output.
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