Pereira, Mário José TeixeiraFiadeiro, PauloJesus, M. E. P.Silvy, Jacques2010-04-282010-04-282002http://hdl.handle.net/10400.6/536The dimensional stability in fibre webs mainly depends of the fibre anisotropy and its orientation on the surfaces. These parameters are influenced during the manufacturing process, where the length and type of the fibres is determinant. The web quality control, in general, is performed based on the measurement of these parameters in the bulk of the fibre webs. This paper presents an optical laser diffraction method to measure the fibre anisotropy and the fibre orientation distribution only at the paper surfaces. The developed system has been successfully used with a set of well-characterised paper sheets. The results shown a high correlation and accurate precision when compared with the results obtained by other techniques. This method has also been used successfully in non-woven fabrics.engFibre orientation distributionPaper replicasLaser diffractionAnisotropyjournal article