Bagging & weighing
The last machine the product touches, and the one your customer judges you by. A bag that is 200 g light is a complaint; one that is 300 g heavy, repeated a thousand times, is a margin problem.
Line composition
Silo → screw feeder → net-weigh scale → bag clamp → settling → sealing → check weigher → flattening → metal detection (optional) → palletising. Each element adds accuracy or speed; skipping one shows up as giveaway or as dust in the packing room.
Where accuracy is lost
- Feeder control: a two-speed screw (fast bulk, slow dribble) is the difference between ±0.5% and ±0.2%
- Weighing on a stable frame — a scale mounted on vibrating structure never repeats
- Bag support during filling; a bag that sags pulls on the load cell
- Product aeration: flake drops predictably, freshly dried warm product does not
- Calibration discipline: weekly check weights, logged, are worth more than a better scale
Range and specifications
| Model | Bag size | Rate | Accuracy | Air |
|---|---|---|---|---|
| GRP-25S | 10–25 kg | 4–6 t/h | ±0.2% | 0.6 m³/min |
| GRP-25D | 25 kg (double spout) | 6–8 t/h | ±0.2% | 1.0 m³/min |
| GRP-50 | 25–50 kg | 8–12 t/h | ±0.2% | 1.2 m³/min |
| GRP-J1 | 500–1,000 kg jumbo | 4–8 bags/h | ±0.3% | 0.8 m³/min |
Rates are for 25 kg PP woven bags with a competent operator. A double-spout machine needs one more person and gives roughly 40% more output.
Design choices worth making early
- 01
Decide the bag, then the machine
PP woven, PE laminated, paper or jumbo — the bag type sets the clamp, the sealing method and the dust control. Changing bags later usually means changing the machine.
- 02
Put the palletiser in the layout now
Even if you buy it in year three, reserve the floor space and the conveyor height. Retrofitting a palletiser into a tight room costs more than the palletiser.
- 03
Dust control is not optional
A bagging room without extraction is a room nobody wants to work in. Enclose the filling point and extract to the scrubber or a dedicated filter.
- 04
Plan for the check weigher
Regulations in many markets require it, and it doubles as your giveaway control. Leave 1.5 m of conveyor for it.
Questions we are asked
How many people does a bagging line need?
A single-spout line with manual palletising: two. Add a palletiser and it becomes one supervisor across two lines.
Can we fill both 25 kg bags and jumbo bags?
Yes, with a changeover kit — different clamp, different feeder, different programme. Allow half a shift to change over and design the space for both.
What is realistic giveaway?
At ±0.2% on a 25 kg bag you are giving away about 50 g a bag. At 6 t/h and 4,000 hours a year that is roughly 48 t of product — worth measuring, and worth the two-speed feeder.