Evaluating an Improved Method to Determine Layered Fiber Orientation by Sheet Splitting

First the most commonly applied methods are reviewed. Then a new method is introduced employing the laminate method for sheet splitting, a high resolution scanner for imaging and fibre segment image analysis for fibre orientation measurement. One advantage of the new method is that it permits arithmetic correction of uneven sheet splitting which reduces noise in the FO measurement.
The main part of the paper is devoted to the evaluation of the new method. Repeatability of the measurement is good. The influence of the sheet splitting process on the measured fibre orientation is assessed by analyzing isotropic laboratory handsheets and oriented machine made sheets. Only minor influence of the sheet splitting on the result is found for handsheets, the measured fibre orientation was nearly isotropic. For oriented paper differences of the measured FO between sheet splitting in MD and CD was found. Overall the effect of sheet splitting on the measured results was lower than expected.
The experiments indicate that the influence of sheet splitting on the measured FO is, although undoubtedly existing, certainly low enough to permit meaningful results. It is discussed, that the predominantly layered structure of the fibres in paper is the reason why sheet splitting can be applied in combination with fibre orientation measurement.