INTERPRETATION OF FORMATION OF PAPER

Flocculation and dispersion processes, and the preferential drainage e ffect on commercial formers have been simulated. This paper outlines t he approach, presents some graphic illustrations of representative str uctures and comments on their analysis for comparison with paper The o bjective is to provide a background for the interpretation of formatio n measurements in the context of process tuning and product design. Re gression equations from Fourdrinier paper allow reasonable predictions to be made of the effects on formation of changes in furnish, refinin g and headbox stock concentration. For example, a 10% worsening of for mation. as measured by the coefficient of variation of local grammage at the 1 mm scale, would be expected from an increase of headbox stock concentration by one third or by an increase of mean fibre length fro m 1 mm to 1. 2 mm. Conversely, a 10% improvement of formation would be expected by an increase in refining of about 16-degrees-SR. Simulatio ns allow a visualization of the formation of different papers, contras ting random, dispersed and flocculated structures.