Twin Folding Tester

For the determination of the folding endurance on paper and board following the Louis.Schopper system. The twin folding tester consists of a robust case, on which two folding heads are attached. The sample supports, which are located to the side, are spring loaded and are opened and closed using a quick latch. To prevent environmental influences an acrylic glass safety cover is attached above the folding tester. A digital display and start and stop buttons are located on the front of the unit.

Test description

Two samples, created with the sample strip cutter, are placed through the folding heads at the same time and clamped in the sample supports with a preset tensile force. Pushing the start button moves the sample swiftly between the folding rolls with a reciprocating action in a radius of 0.25mm. This folds the test strips in both directions. If one of the samples breaks, the folding operation continues on the second sample until this also breaks. Then the units stops automatically and the number of folds before breaking is shown on the digital display. Because of the quite large standard deviation, two samples are always tested simultaneously. To ensure correct test behaviour the test should be carried out under suitable climatic conditions (23 °C / 50% RH).