Induction sealer sealing-window setup sheet
A practical guide for recording the power, speed, head-height and pack details that create a repeatable induction foil seal.
What a sealing window means
A sealing window is the range where the induction field gives enough energy to bond the foil liner to the container mouth without burning the liner, distorting the closure or leaving weak edges. The window is found by testing the actual cap, liner, container and conveyor conditions, not by relying on a published machine speed alone.
For production use, the setup record should show the accepted setting and the nearby rejected settings. That gives operators a practical boundary when they return to the line after cleaning or changeover.
Setup fields to capture
| Field | Cap outside diameter, cap type, liner construction, container material, neck finish, product, fill level, conveyor speed, head height, power setting and cooling time before checks. |
|---|---|
| Trial range | Test below target, at target and above target line speed where practical. Record whether each point passed visual, peel and leak checks. |
| Operator note | Record any handling issue such as unstable bottles, loose caps, liner movement or product contamination around the mouth. |
How to use the sheet after installation
Use a separate setup line for each cap and liner group. A contract packer with several customers may need multiple records even when the same machine is used. The aim is to avoid treating one accepted setting as universal across unrelated packs.
Frequently asked questions
Can one setup sheet cover all cap sizes?
No. A separate line should be kept for each cap and liner group because diameter, liner construction and container material can change the sealing window.
Should the sheet include rejected settings?
Yes. Rejected settings help define the boundary between under-sealing, accepted sealing and overheating.
Does the published maximum speed replace setup testing?
No. Published speed is model and pack dependent. The accepted speed should be recorded after checking the actual pack.
Who should keep the setup sheet?
The production or quality team should keep it with other line setup records so operators can repeat the approved settings.
Need help applying this to your pack?
Send Lancing UK your cap, liner, bottle and line-speed details so the induction sealing route can be checked before quotation.
Treat a component change as a reason to review the setup.
A new cap, liner code, container supplier, neck-finish revision or product condition can change the practical sealing window. Add revision and approval fields to the setup sheet so operators know which record applies to the batch being run.
| Revision trigger | New liner, cap, bottle, head, conveyor speed range, control software or acceptance method. |
|---|---|
| Evidence | Supplier code, sample batch, accepted settings, rejected limits and approval date. |
| Release | Name or role authorised to approve the revised production setup. |
Choose a repeatable setting inside the demonstrated sealing window
A passing induction seal at one power setting is a starting point, not a useful operating window. Establish the low and high boundaries using the approved pack and inspection method, then select a working point with demonstrated margin from both under-sealing and overheating. Do not choose a production setting simply because it was the first sample that passed.
Before changing power, check the variables that determine exposure: the container path under the head, head clearance, actual conveyor speed and closure application condition. Record measured speed where possible rather than assuming the drive display gives the bottle speed. Keep cap, liner and bottle identities fixed while establishing the first comparison.
Then challenge the selected working point at the operating variations the line is expected to encounter. Use only the agreed safe trial range and keep failed samples identified. Record which nearby combinations remain acceptable and which do not; avoid combining separate successful settings into an untested recipe. The approved sheet should describe the verified combination and the response when a required condition is outside its range. This gives operators a repeatable return-to-production reference.
Should the production setting be the first power level that seals?
No. Establish both boundaries and choose a demonstrated operating point with margin from under-sealing and overheating.
Why check conveyor speed before increasing induction power?
Speed changes exposure beneath the sealing head. A speed or alignment error can resemble insufficient power and should be resolved first.
Check closure application conditions Define seal test acceptance