The Flat Crush Test

In the flat crush test, a single-flute corrugated-board specimen is loaded perpendicular to its surface. The resistance this corrugated board presents to the force provides an indication of its behavior during processing and in use. 

A typical curve is in accordance with the height of the individual flutes, with the highest flutes collapsing first, then the middle ones, followed by the remaining flutes at the end of the test.

If the corrugated board has been pre-damaged, the curve is fundamentally different. The crush energy and curve provide indications of the potential damage level.

Modern miniature flutes tend to collapse only under forces greater than 10 kN, requiring extremely high lateral stiffness in the compression platens. Suitable platens are available from Zwick for  these applications also.

Standards for this test are ISO 3035, EN 23035 and TAPPI T 825.