Lloyd Instruments, a brand under AMETEK TCI, has developed a special jig for easy determination of peel strength of the aluminum foil on contact lens blister packs. Designed for use with a low force tester, such as the LS1 materials testing machine
, the jig features a self-adjusting sliding bed for true 90° peel tests.
The blister pack testing jig has been engineered for use with two contact lens blister packs, each containing individual lenses in a solution. One lens pack is clamped in the upper instrument grip, whilst the other is clamped and fitted into a special mount in the jig’s sliding baseplate. As the test machine’s crosshead is driven upwards, peeling the foil on the lower blister pack, the baseplate slides horizontally, to ensure that the peel force is always applied vertically.
Peel strength is an important parameter to be measured for contact lens packages. Too high a strength and the blister package is difficult to open and there is the risk of a sudden opening resulting in the lens and fluid being accidentally ejected. If the peel strength is too low, there is a chance that the foil lid could be detached accidentally, for instance when carried in a bag or pocket, with loss of fluid and damage to the lens.
With material testing and force measurements up to 1 kN (225 lbf), test speeds from 0.05 to 1270 mm/min and accuracy greater than 0.2% the LS1 materials tester
is ideally suited to peel test applications of this type. Tests can be fully automated through the addition of the NEXYGENPlus materials testing software