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J. Mardon, R.E. Monahan, R.A. Carter and J.E. Wilder. Dynamic consolidation of paper during calendering: dynamic compressibility of paper. In Consolidation of the Paper Web, Trans. of the IIIrd Fund. Res. Symp. Cambridge, 1965, (F. Bolam, ed.), pp 576–626, FRC, Manchester, 2018.


Two dynamic compressibility testers are described and the accuracy of one of them is examined by means of an energy balance and found to be within 5 per cent. The relationship of dynamic and static compressibility is discussed, the effects of moisture and temperature briefly examined and the results of testing a number of papers on the dynamic tester are presented. The changes in compressibility through the calender stack of two papers are given as examples and the dwell time/pressure relationship for caliper reduction is given for three different papers. Printability is examined as a function of compressibility and the relative compression of press packing and various papers is examined. A graphical method for determining the specific pressure distribution in a calender nip is given and the implications of the results are discussed. Two extreme cases of materials in a calender nip, one completely elastic, the other completely plastic are briefly discussed and a rheological model for the calender action is presented in an appendix.

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