The bending stiffness is a of major importance for the top-to-bottom stacking strength of a finished box, as well as its ability to resist buckling. Bending stiffness is closely related to the thickness of the corrugated board material and the quality of the outer and inner liner layers.
These factors may change during production, thus reducing the quality of the finished product. Routine testing of the bending stiffness of corrugated board, before and after converting, is therefore the obvious solution.
Previous methods for measuring bending stiffness of corrugated board have involved severe accuracy problems. The 4-point bending method, as performed by L&W 4-point Bending Stiffness Tester, avoids the influence of twist and warp. The clamp design ensures that the test piece is kept flat at the beginning of the measurement. This makes the test results very dependable. To prevent errors because of shear forces introduced during bending the test piece, one of the clamp rotation points are fixed and the other can move in horizontal direction.
- Ease of use:
– Large touch screen for good overview
– Intuitive user interface
– Fully automated testing sequence
– Recommended settings for different flute types are pre-programmed
- Accurate measurements:
– Pneumatic clamping effectively eliminates any problems with twisted and curled test pieces