QC – Monitor

December 6, 2005 - There are numerous causes that can affect quality of a tamper evident seal. Most of them can be quickly investigated and rectified by simple visual and manual checking of the possible problems such as:

• Incorrect cap torque – too much or too little
• Cocked cap
• Imperfections in the container finish (bad lip)
• Conveyor speed – too high or too low
• Aluminum foil thickness
• Thickness of wax layer
• Quality of backing – Insufficient wax absorption
• Incompatibility between the liner and container material
• Coupling distance between the sealing head and the container – too much or too little
• Output power from the energy unit – too high or too low
• Misalignment of the cap under the sealing head

Once, however, the system is set up properly, giving good sealing results, there is a need to be able to periodically check the sealing line conditions, to guarantee consistent performance. This kind of testing must be done with the line running, and without stopping the production.

The first thing to check should be whether the foil is getting enough heating energy. This cannot be done by a visual method; a special monitoring system must be used.

LEPEL CORP, the originator of the cap-sealing systems, has come up with the most accurate way to measure sealing energy at the sealing foil. This innovative design measures the sealing energy at the exact position of the foil, including the same variables that the package sees, providing for the more precise detection of sealing problems.

The QC – Monitor system consists of two devices:

1. Battery – operated Electromagnetic field Sensor with a built-in Transmitter
2. Battery – operated Receiver and information Processor with Display, which can be via RS-232/USB be connected to a computer for more detailed information and Quality Control Management

The QC – Monitor gathers and displays a wealth of information crucial for smooth operation of a cap sealing line.

The parameters measured are:

1. Time of cap exposure to the electromagnetic field. Measurements are taken every two milliseconds

2. Field strength at every measured point.

3. Average field strength during the cap passage under the sealing head.

4. Total energy of exposure which is ultimately responsible for a good seal

5. Once the "good seal" window is established the instrument shows GO/NO GO condition for every test run

6. Using computer hook-up, the complete field strength vs. time plot can be shown and checked for discontinuities, which would indicate partial or full sort circuit inside the sealing head.

7. The unit measure frequency of the field.

8. By entering information for coil length one can measure the line speed.

9. The unit displays how many more measurements can be done with the same battery in the sensor. Around 8,000 measurements can be made With a new battery.

10. The unit displays battery status for both, sensor and receiver.

11. Information for "good seal" parameters for eight different liners can be stored and compared to the new readings during the operation.