Testing was required for a range of flexible plastic trays of the same dimension but with differing forms, containing biscuits and confectionary. The adhesive bond on the clear foil sealing the trays needed to be tested for peeling strength.
The system needed a constant peel speed at a constant angle of 90 degrees. A reading of the peak force to break the adhesive bond, together with the average force to maintain the peel was required. With a number of plastic trays to be tested, the test speed needed to be as high as possible (500 mm/min).
The plastic trays were too flexible to be held by a mechanical grip, so a 'rotating vacuum fixture' was developed. This held the tray firmly in place during the test. A compressor providing 6 bar pressure was required with the vacuum being controlled by a lever-valve. To accept the different forms of plastic trays, a range of dedicated inserts were supplied with the vacuum fixture.
Both the vacuum and force gauge were mounted at 45 degrees to provide the constant angle of 90 degrees. In order to maintain the constant peel speed. The vacuum fixture was able to freely rotate on a bearing allowing the rectangular shaped plastic tray to self-centre during the test. DataPlot software enabled the customer to analyse peak and and average forces in a graphical format.
McVities, UK
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Mecmesin Ltd A PPT Holdings Company |
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