DIN 53121

Bending Resistance Standard

Bending resistance measurements for industrial substrates follow specific mechanical criteria to ensure structural uniformity. Din 53121 provides the technical framework for measuring stiffness using the beam method or the resonance method. This standard ensures that different laboratories produce comparable data for the structural rigidity of packaging materials.

It defines the dimensions of the test pieces and the speed at which the force must be applied.

Testing Procedure

The beam method requires a strip of board to be clamped at one end and deflected at the other by a measured force. Under the rules of din 53121, the force is recorded when the sample reaches a specific angle, often two or five degrees. This measurement helps designers calculate whether a carton will bulge when filled with a product.

Calculations based on the thickness and the force applied yield the bending modulus. Precise control of the environment is necessary because the moisture in the fibres significantly changes the stiffness of the board.

Industrial Application

Converters use the values derived from this standard to select the appropriate grade of board for specific box sizes. Compliance with din 53121 allows suppliers to guarantee that the substrate will perform correctly on high-speed packaging lines.

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