Inconsistent seal strength is one of the most elusive yet troublesome issues facing flexible packaging manufacturers. Many quality control professionals treat a "pass" on leak tests as a safeguard, only to face customer complaints regarding ruptured bags and leakage during transit. The root cause often lies not in the leak detection process itself, but in the sealing stage—specifically, a failure to achieve a secure seal. This article begins by explaining the adjustment logic of heat-sealing testers and clarifies how the three key parameters—temperature, pressure, and dwell time—affect seal strength.
