Set induction cap-sealer power by validating the complete liner system, not by foil thickness alone: begin at minimum power and increase by 1–2% per test container until the seal quality is acceptable [S3].
Why foil thickness alone cannot set power
Induction cap sealing heats a conductive liner until its outer polymer layer melts and bonds to the container lip. An induction sealing machine features two standard components: the power supply and sealing head [S3].
Foil thickness is therefore one variable in an energy transfer problem, not an independent power prescription. A thicker liner may require more energy to heat, but its conductivity, aluminum or foil structure, adhesive formulation, closure material, and available dwell time can change the required machine setting.
Once those conditions are fixed, field strength becomes a practical adjustment variable alongside the liner path through the field and the time the liner remains in that field [S1].
A controlled starting procedure
Begin at the machine's minimum power setting, seal one container, and inspect the result before changing the setting [S3].
Cap torque also belongs in the setup record.
Power, time, and air gap comparison
Power, sealing time, and air gap should be compared as coupled controls rather than independent recipes. The sealing head and power supply determine the electromagnetic heating condition, while dwell time determines how long the liner receives that condition [S3][S6].
Material and container constraints
These constructions differ in heat-transfer and post-seal behavior, so their validated settings should not be transferred without testing.
Compatibility also depends on the container and closure material.
Acceptance tests and failure diagnosis
A 38 mm liner provides one practical torque reference: the rule of thumb is one-half of liner diameter in millimeters as torque in inch-pounds, giving 19 inch-pounds for a 38 mm liner [S2].
Production controls for foil-thickness changes
Machine output is not the only available energy control. The field strength is governed by the cap sealer's power level, with 100% representing maximum power, but more power does not necessarily produce a better seal [S1]. Voltage, power, induction strength, and sealing time should be adjusted to the container size, shape, and cap type when establishing a new recipe [S5].
For a foil-thickness change, do not raise the power percentage and extend dwell time together. First verify whether the new liner code, closure geometry, and container material have changed. Then run a controlled power sweep at the existing dwell time, retain the best passing setting, and confirm that the operating window remains stable at production line speed.
Track the first-pass seal result, line speed in containers per minute, power percentage, dwell time in milliseconds, air gap in millimeters, and observed failure mode for each liner revision. A recurring weak-seal result calls for renewed validation of liner construction and closure torque; a recurring burn result calls for reduced thermal input. The next verifiable node is a documented operating window for each specific liner and closure pairing, not a generic foil-thickness-to-watts formula.