Sliding and separating put different loads on the film
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A sled pulls one film along another under a set normal load. Blocking shows up when surfaces that have been in contact resist being pulled apart. Two sheets may slide easily in a short test yet cling together after spending time pressed against each other. Pressure, temperature, storage duration and the faces touching all matter when reproducing that behavior.
Recreate the stack as well as the slide
Suppose cut overwrap sheets pass their sliding check but pick up in pairs after storage. Record how the sheets were stacked and identify the two touching faces. Use a defined blocking test or a separate stack trial that controls the load, duration and temperature, and record how the sheets are separated. Keep the sliding measurement as a separate result so the team can see which behavior changed.
For a laboratory comparison, ASTM D3354 describes a parallel-plate method for blocking load. A sheet-feeding trial can then check whether the effect matters to the actual picking mechanism.
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