Burned cardboard liner
1. Excessive power from sealer: conveyor set too slow, power set to high.
2. Bottle backup under sealing head.
3. Insufficient cap application torque
Cap extremely difficult to remove (2-piece liner)
1. Insufficient power from sealer:conveyor set too fast, power set too low (insufficient wax melt).
2. Improper coil height, coil too high.
3. Excessive cap application torque.
4. Foam liner polymer welds to polymer in induction liner.
If the power output is steady and one container seals, all should seal. The fault is not with the induction sealer. Check to make sure the caps are all being torqued evenly and are not cocked. Also check the bottle seating areas for uneven surfaces, burrs, etc.
Insufficient sealing power
Metal guide rails located too close to sealing head. Guide rails under sealing head should not be metal because they can distort the electromagnetic field.
Low or no removal torque
1. Insufficient cap application torque: closure not securely applied.
2. Excessive application torque: threads of closure stripped.
Partial, weak, or no seal
1. Insufficient power from sealer: conveyor set too fast, power set too low.
2. Improper coil height.
3. Insufficient torque on cap.
4. Induction liner incompatible with bottle material.
5. Bottle neck finish has been flame or chemically treated.
6. Imperfections in container finish, land area.
Excessive power from sealer: conveyor set too slow, power set too high.
Pinwheel effect on liner
Retorquing too soon after induction sealing.
Seal extremely difficult to remove (1-piece liner)
1.Excessive power from sealer.
2.Liner larger than neck, creates overhang.