ISO 5628 Standard Test for Paper and Cardboard, Determination of Flexural Rigidity, Two-Point, Three-Point, and Four-Point Methods

EUROLAB laboratory provides testing and compliance services within the scope of ISO 5628 test standard. This standard specifies three test methods for determining the bending stiffness of paper and board. Test methods differ in the type of loading mode, thus leading to two-point, three-point and four-point bending test methods.

Two-point bending method and three-point bending method are suitable for paper and cardboard in the low thickness range. For corrugated board and thicker boards, the four-point bending method is recommended.

The measurement conditions are defined so that the test piece is not subjected to any significant permanent deformation during testing and the validity range of the formulas for calculating the bending stiffness is not exceeded.

Flexural stiffness is considered an important property of paper and board, and numerous test methods have been used to determine it. This is, at least in part, a result of the wide range in bending stiffness of paper and board. For paper and board in the weight range of 50 g/m2 to 500 g/m2, the bending stiffness can vary by a factor of over 1000. This wide diversity is reflected in the design of instruments for measuring this property.

EUROLAB assists manufacturers with ISO 5628 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.