An impulse sealer heats a wire only while the jaw is closed, drawing no standing power and suiting short, intermittent runs. A continuous band sealer holds its heaters at temperature and carries the bag through on belts, sealing without an operator pause: the right choice once runs are continuous.
Duty cycle is the deciding factor
Impulse sealing is intermittent by design: the element heats, the seal forms, the jaw cools before release. Push it faster and the element cannot recover, seals get inconsistent and element life drops. Band sealing is continuous: heaters sit at a set temperature and belt speed governs dwell.
Band sealer vs impulse sealer
| Impulse sealer | Continuous band sealer | |
|---|---|---|
| Heating | On demand, per seal | Held at constant temperature |
| Operator | Positions and presses each bag | Feeds the bag; belts carry it |
| Run length | Short and intermittent | Continuous production |
| Coding | Not integrated | Solid-ink or inkjet coder runs in line |
| Orientation | Bench, bag flat | Horizontal or vertical models |
| Standing power | None between seals | Continuous while at temperature |
What the specifications look like in practice
Across the 25 sealing series we supply, published belt speeds run about 8–24 m/min and sealing power about 300–2000 W. Faster belt speed shortens dwell, so speed and temperature are always specified together, never independently.
Where each one fails
Impulse sealers fail on thick or multi-layer film: the element cannot hold enough energy through the jaw dwell to fuse the inner layers, so the seal looks closed and peels open. Band sealers fail on very short runs, because you pay warm-up and standing energy for a handful of bags.
Compare horizontal, vertical, pedal and hand sealing formats in the sealing range.
Figures in this article are drawn from the 137 machine series SilverSeal currently supplies, not from generic industry averages. Specifications vary by model — check the individual series page before specifying.
Frequently asked questions
Can a band sealer handle foil laminates?
Yes, provided temperature and belt speed suit the laminate. Thick foil laminates need a slower belt so heaters have dwell to fuse the sealant layer.
Why does my impulse seal look sealed but pull apart?
Usually insufficient energy through the inner layers: the outer layer welds and the sealant does not. Longer dwell or a different sealing method is needed.
Do band sealers need a warm-up period?
Yes. Heaters must reach and stabilise at the set temperature before the first production seal, otherwise the first bags run cold.
Can a coder be fitted to a band sealer?
Yes. Solid-ink and inkjet coders are commonly fitted in line so the date or lot code is applied during the same pass as the seal.
