Longitudinal seal monitoring

In many flexible packaging applications such as flow-pack or VFFS packaging, the film is pre-formed with a continuous longitudinal seal before the package is filled and sealed. It is important to continuously monitor the quality of the longitudinal seal as poorly sealed packages can also lead to leaks or ripped packages. Engilico offers different solutions to monitor the quality of the longitudinal seal, made by heat sealing, impulse sealing or ultrasonic sealing. This new functionality enables to check overlap and/or the temperature differences in the longitudinal seal by adding ultrasonic web edge sensor(s) and/or Infrared temperature sensor(s) or infrared camera (s). Using the temperature differences, it can also detect systematic errors such as incorrect mechanical set-up of the longitudinal seal bar or failure of a heat element. These functions are directly integrated in SealScope™, leading to better quality and higher productivity


  • Longitudinal seal is important for global packaging quality
  • Monitors parameters that influence quality of longitudinal seal
  • Applicable for flow-pack and VFFS packaging machines
  • Fully integrated in SealScope™
  • Retrofit possible for existing SealScope™ installations

Packaging film position

A correct overlap of the longitudinal seal is important to guarantee the seal integrity. A sensor monitors the position of the packaging film before it is folded over the forming shoulders. SealScope checks that the packaging film is not fed outside of desirable position, as this can lead to incorrect or varying overlap of the seal.

Seal temperature as a measure for seal strength

A key parameter for a qualitative longitudinal seal is the correct temperature of the sealing process, as this will define the seal strength. Too low temperatures will prevent the sealing process, while too high temperatures can burn the seal. SealScope™ monitors the temperature of seal during or after the sealing process using a dedicated sensor to verify if it is in between the correct boundaries.

Seal bar pressure

The pressure that is applied to the sealing jaw or knife to form the longitudinal seal is also important for the seal quality. By using a dedicated sensor, SealScope™ monitors the pressure during the forming process. When deviating from a user defined value, SealScope™ will issue a warning signal to eject faulty package.

Contact us for more information or to validate if the Longitudinal Seal Monitoring functionality is applicable for you.