ISO 5629:2017 pdf download

ISO 5629:2017 pdf download.Paper and board — Determination of bending stiffness — Resonance method
1 Scope
This document specifies a method for the determination of bending stiffness using the resonance method.
This method gives only a single result for each test piece tested, although in general, bending stiffness values may depend on which surface of the material forms the inner surface of the arc resulting from bending forces.
The bending stiffness of a very wide range of papers and boards can be measured using this method.
However, for some materials, such as those listed below, the measured numerical values will not be strictly identical with bending stiffness as defined in 3.1:
a) multi-ply papers and boards in which the component plies can move separately during a test;
b) papers and boards with appreciable curl, especially if the axis of the curl is in the long direction of the test piece;
c) some soft papers with grammage below about 40 g/m 2 .
This method is not applicable to corrugated boards.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 186, Paper and board — Sampling to determine average quality
ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples
ISO 536, Paper and board — Determination of grammage
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
8 Preparation of the test piece
Cut at least one test piece of appropriate dimensions from each of the specimens in each of the desired test directions. If watermarks are present, this should be stated in the test report. The dimensions of the test piece are dependent on the type of material. In general terms, the width of the test piece shall be between 10 mm and 25 mm. The edges shall be clean, straight and parallel to within ±0,1 mm. For papers of low grammage and for materials with a tendency to curl perpendicularly to the test piece length, a width of 10 mm or 15 mm is preferred. For materials of higher grammage, a width of 25 mm is preferred. The length of the test piece shall be sufficient to allow for the projecting length at resonance and the depth of the clamp, together with a sufficient length to permit handling of the test piece in the non- resonating area and attachment to the lower sample clamp (if fitted). The resonating end of the test piece shall be clean, straight and perpendicular to the long edges of the test piece in both axes. If procedure A (see 9.2) is to be used, the dimensions of each test piece shall be measured accurately.