Induction sealer conveyor speed and dwell time guide
Use this guide to connect line speed, power setting and head position when specifying or troubleshooting an inline induction sealer.
Why does conveyor speed affect induction sealing?
Conveyor speed controls how long the capped container remains under the induction field. If speed increases, dwell time falls. The machine may then need a different power setting, head position or bottle spacing, but those adjustments must be proven with the actual cap, liner and container rather than copied from another pack.
The practical output of an induction sealing line depends on the relationship between the machine, pack and conveyor. A model-dependent maximum speed reference is useful for shortlisting, but the accepted production speed should come from sample evidence at the intended line conditions.
| Variable | What it changes | Evidence to keep |
|---|---|---|
| Conveyor speed | Time available for the foil layer to heat. | Accepted low, target and high speed settings. |
| Power setting | Energy delivered to the foil during the dwell period. | Power value paired with cap, liner, speed and head height. |
| Head height | Relationship between the induction field and the foil position. | Documented setting or adjustment reference for each format. |
| Bottle spacing | How consistently containers enter and leave the field and any downstream inspection. | Pitch, guide setting and conveyor transfer notes. |
| Cap diameter | Area to be heated and the head option required. | Measured closure range and selected head. |
How should a sealing window be built?
A sealing window is the practical range of settings that produces an accepted seal without overheating, weak bonding or random failures. Start with one representative pack, prove an acceptable setting, then test reasonable boundary conditions. Do not assume that the largest cap, smallest cap or widest mouth will behave the same.
- Confirm the correct liner and cap application before changing machine settings.
- Set a stable conveyor speed and align the head over the pack path.
- Increase or reduce power gradually and record each result.
- Allow the seal to cool before peel or leak checking.
- Repeat the accepted setting after a stop and restart.
- Retain accepted and failed samples where the quality process requires evidence.
What can go wrong if speed and power are not recorded together?
A setting that works at one speed may fail at another because dwell time has changed. Weak seals can appear when the foil does not receive enough heat for long enough; scorched, distorted or difficult-to-peel seals can appear when the pack receives too much energy for its conditions. Random results can also be caused by unstable conveying, bad cap pressure or liner variation.
For multi-SKU lines, the setup sheet should record speed and power together. Treat each cap and liner group as a separate record until evidence shows that the same setting can be reused safely.