A system was required to measure the tension force necessary to initiate the peel of a plastic foil lid from a plastic container.
The angle of peel needed to be the same as when a user opens the container (135 degrees as specified by the customer). The peel initiation was considered complete when the foil had been pulled by approximately 5mm.
A simple vacuum fixture was developed to hold the plastic container without it deforming. The container was held by a mechanical gripping fixture so as not to compress the air inside causing the foil lid to arch upwards and affect the results.
The vacuum fixture required a compressor operating at 6 bar (not supplied) and was controlled by a toggle lever to hold/release the container. The force gauge was positioned on an arm from the motorised test stand directly above the inclined container. A pin vice with flexible chain allowed the operator to easily grip the foil tab and then connect the chain to the fixed hook of the force gauge.
A 'drip' tray and a Perspex splash guard provided protection from any escaping liquid. The force was recorded on the gauge and sent to the mini-printer.