Cap torque and induction sealing
Cap torque is one of the most common causes of inconsistent induction seals. The cap has to hold the foil liner in reliable contact with the container mouth while the foil is heated by the induction field.
Too little torque
If the cap is too loose, the liner may not sit flat against the mouth. That can cause weak areas, incomplete bonding or leakage paths even when the induction power setting appears correct.
Too much torque
Over-tightening can distort closures, damage liners or make the pack difficult to open. It can also create inconsistent pressure if the cap or thread design is not stable.
Best practice checks
Record the intended torque range, test it with the actual cap and bottle, and re-check after capping machine changeovers. If seal quality changes, check torque before increasing power.
For a faster recommendation, send cap diameter, liner type, container material, bottle height, conveyor details and target output to Lancing UK.
Related induction sealing resources
Use these pages to continue narrowing the machine specification and enquiry information.
Troubleshooting Induction Seals
Continue comparing induction sealer requirements, foil liner compatibility and line setup before requesting a quote.
Foil Liner Compatibility Guide
Continue comparing induction sealer requirements, foil liner compatibility and line setup before requesting a quote.
Automatic Induction Foil Sealing Machine UK
Continue comparing induction sealer requirements, foil liner compatibility and line setup before requesting a quote.
Need help with this induction sealing application?
Send your pack details to Lancing UK and we will help identify the correct induction sealing route.
Use the closure supplier's range and a repeatable measurement method.
Published rules of thumb are not a substitute for the accepted cap-and-container specification. Measure torque using the site's approved instrument and method, and record removal or application values consistently so good and failed packs can be compared.
Enercon's technical explanation illustrates why even liner contact around the full circumference depends on consistent application pressure, but the final range must be established for the actual closure system.
| Too low | Liner may not contact the full rim, allowing partial or intermittent bonding. |
|---|---|
| Too high | Some caps or containers can distort, thread poorly or create other closure problems. |
| Variable | The same induction setting can produce mixed results because contact pressure changes from pack to pack. |
| Response | Correct the cap application process before using induction power to mask the variation. |