In the 4-point flexure test the bending stiffness of corrugated boards is determined in accordance with DIN 53121 or ISO 5628. The 4-point flexure test delivers reliable stiffness values in the machine and transverse directions. This is particularly important for mini-flute corrugated board, where the stiffness of the board plays a significantly greater role than with standard flute heights.
4-point flexure test on corrugated board as per DIN 53121
4-point flexure test on corrugated board as per DIN 53121, zwickiLine, paper industry
Using expertise gained from flexure test kits for structural materials, (aerospace, ceramics and high-performance metals), Zwick Roell has developed a 4-point flexure test kit for cardboard and corrugated cardboard.
The result is a moderately priced fixture which meets all requirements Another important point is that it can even be used with our smallest machine, the zwicki.
In contrast to instruments that use weights for specimen loading, operation is quick and straightforward. The specimen is simply positioned on the flexure test kit and the test is started. Stiffness is calculated automatically, with allowance for elastic limits.
The anvils supplied with the flexure test kit are designed to fully accommodate the properties of corrugated cardboard, allowing even warped or buckled specimens to be tested in many cases.
Measurement is possible even with production-related self-deformation of specimens.