Taber Bending Stiffness

Test Methodology

Measurement involves clamping one end of the sample and applying a load to the free end until it reaches a fifteen-degree deflection. The result is recorded in Taber units or millinewton metres, depending on the region and the specific instrument. Stiffness varies between the machine direction and the cross direction of the board.

Multi-ply constructions use high-bulk centres to maximize this value without adding excessive weight. Accurate testing requires samples to be conditioned at a standard temperature and humidity. The internal bond strength of the layers must be high enough to prevent delamination during the test.

Structural Performance

Cartons with low stiffness may bulge or collapse when filled on high-speed lines. Designers use these figures to calculate the maximum height of a pallet or the weight a box can support. Consistent stiffness ensures that the creasing and folding operations remain predictable during converting.