Common Causes of Seal Leaks:
Insufficient Heat Seal Temperature: During the production process, variations in the thickness of the composite film are a major factor affecting the variation of bag-making seal parameters. Deviations in product thickness can lead to fluctuations in the thickness of the composite film, posing difficulties in controlling seal parameters. Local seal leaks may occur due to an increase in film thickness, which increases heat transfer and requires adjustments to time or temperature. In addition, uneven thickness can affect the setting of temperature and pressure values. The most reliable method to check for local seal leaks is to take continuous samples at the lowest temperature point within the temperature range.
Equipment and Operational Issues: Foreign objects caught in the heat-sealing film, insufficient heat-sealing pressure, or uneven mold surfaces may lead to local heat-sealing problems. Temperature variations in different parts of the heat-sealing mold or non-parallel installation can also be contributing factors.
Issues with Packaging Materials: Corona discharge or excessive slip agent in the heat-sealing layer can result in poor heat sealing.
Structural Seal Leaks: Specialized areas with sudden changes in thickness, such as edge inserts, back seals, or bottom-sealed bags, may experience seal leaks if the resin is not adequately fused. Problems are likely to occur at the back seal or at the overlap of the side-sealed bag's edge seal with the top seal. Solutions may involve increasing temperature, pressure, or implementing localized reinforcement.