The first stage of the project involved setting up laboratory trials at Ceetak using a vertical form‐fill seal bagging machine to test the prototype designs and establish their operating parameters. Film samples were obtained from all the manufacturing partners for the trials and retail packs were purchased so that filled bags could be tested. The seal quality was measured by a combination of vacuum immersion tank tests and, penetrative dye tests. Optimum settings were found for each material type which produced hermetic seals. Designs were then finalised for commercial scale trials, and rigs constructed.
Figure 1: Test rig at Ceetak
Figure 2: The prototype intermittent design
Figure 3: The prototype continuous design
The second stage of the project involved setting up the new rigs on production machines at each of the partner companies to run trials under commercial conditions. Fresh leaf salad was run at Tilmanstone Salads and Soleco UK Ltd on Sandiacre and Ilapak machines respectively.
During the trial the following data was collected:
- Machine speed
- Strength of the seal - Vacuum immersion tank test
- Micro leak level – penetrative dye test
- Life of the jaw components
- Machine Operator interface
- Engineering maintenance issues