NC State
H.W. Kropholler and T.J. Prior. An evaluation of the factors affecting perforation quality. In Products of Papermaking, Trans. of the Xth Fund. Res. Symp. Oxford, 1993, (C.F. Baker, ed.), pp 1023–1044, FRC, Manchester, 2018


Samples of two types of carton board, a coated white line chip (WLC) and a folding boxboard (FBB), were perforated using an experimental cutting forme. Variations such as depth of cut and rule condition were introduced. These samples were then torn using an Elmendorf tear tester and assessed for their mode of failure. The results indicate that the detrimental effects of worn rules and poor cutting depth can be magnified by the size and relationship of certain board properties, particularly tear and plybond strength. The test results and micrographs suggest an unaided visual examination of the perforated line is insufficient to guarantee clean tearing, particularly when worn rules have been used.

The effect of the pronounced directionality in the WLC has been demonstrated with regards to the perforation performance. The results have also indicated that plybond/tear ratio is significant in the mode of failure. The usefulness of transmitted light coupled with magnification has been shown with respect to the examination of perforations for quality control purposes. This holds possibilities within QCasa method of assessment.

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