Check invisible LDPE sealing seams
After automatic filling, the bag is sealed by means of a sealing bar through which electricity runs. The heat of the heating element causes the LDPE to melt. Because the LDPE is on the inside of the paper bag, it is not possible to visually check whether the seal is properly formed. Possible mechanical defects during the filling of a paper bag are:
- The seal was not fully sealed because milk powder remained between the seal during the sealing process.
- The bag is not properly loaded on the sealing bar so that part of it did not have a contact surface with the paper bag.
- Contamination of the sealbeams therefore the seal seam is not well formed.
Seal seam integrity check pharmaceutical industry
Because it is a high-quality product supplied to the pharmaceutical industry, the packaging must be checked for seal seam integrity.
Vision Partners has developed an inspection solution consisting of a high resolution IP66 thermal imaging camera (640 * 480 pixels) which takes a thermal image of the packaging seal. The LPDE seal is clearly visible on the thermal image. The image capture is triggered by a sensor on the outgoing conveyor belt. There is a control cabinet including a touch screen on which the operator can directly see the progress of the control including the recorded images.
Different types of sealing errors
By analyzing the thermal image of the seal with machine vision software, different types of faults can be identified such as:
- Contamination between the seal
- Crumpled seal due to crumpled paper and/or folded ends
- Sealbeam defects
At the same time, all recorded images and data are stored on the vision PC so that they are also immediately available to the production and quality staff.
“We have now been able to make the transition from a costly destructive sample test to a process where we contactlessly monitor the heat profile of every seal seam.”
A satisfied production manager
