Formation measurement and paper quality

People will agree that uniformity is an important factor in determining the quality of paper. However, the relationship between the formation and the quality of the paper is very complicated, and of course it involves other variables.
Assuming that the visual homogeneity of stereotypes is only the quality of paper, there is a one-to-one dependency between them, which may be oversimplified. However, it is hard to say how well the formation of the paper will play a role. From a theoretical point of view, in addition to the formation sensor on the paper machine, it is worthwhile to install an online sensor. Depending on the variety, quantitative, thickness, surface roughness, optical properties, moisture, ash, elasticity, and moisture content are determined.
There are many explanations for the formation uniformity terminology. We still do not have a unified definition or measurement standard. Although generalized uniformity index (1) has been proposed. Forming is generally associated with changes in the micrograms of paper and board, such as in the range of 0.1 mm to 100 mm. This may also be related to minor changes in the nature of paper, such as the nature of school-related issues, porosity, thermal properties, surface roughness, surface energy, and so on. Even though we have a satisfactory instrument to determine the uniformity, such as micrograms, there are many methods of determination, in which methods such data (2, 3, and 4) may be used to indicate the results. When we consider the distribution of other papermaking raw materials such as fillers, sizing agents and coatings, the situation may be more complicated.

î—¥ î—¥ Continually emphasize the quality of paper, it should pay more attention to the formation of the paper machine and humidity. As mentioned earlier, there is a relationship between formation and trace quantitative changes, so it is impossible to consider what changes in independent factors have occurred macroscopically. In the most recent data, Parker and Moore mentioned a new paper web monitoring method that can effectively provide five orders of magnitude of forming variation data, for example from 1 to 1 x 105 mm. It is interesting to be able to see how one length-level change affects other issues. Quantitative large, medium, and small changes are estimated to be important for the processing and final use properties of paper and board. However, what specific impact they have has yet to be further studied.
 good evenness can improve the quality of the paper, despite the lack of intuitive data, but efforts to improve the evenness has not stopped. In general, we believe that when the headbox concentration increases, the uniformity decreases. Also, improving the directionality of the fiber arrangement, especially for the old headbox, also has an adverse effect on the uniformity. However, the newly developed twin-wire formers and web formers not only improve the directionality of the paper, but also present unique insights that the design of the headbox and the disturbance of the pulp flow influence the quantification of the paper in varying degrees. rate.
The formation measurement methods include optical technologies such as laser, video C14 beta radiographs, beta light source P147, X-ray and electron beam technologies. Nearly all commercially used off-machine and in-machine uniformity analyzers use transmitted light, use reflected light under certain conditions, and utilize various scanning methods. Formability is also an important factor in the use of cardboard, especially for hanging panel paper, and it is hoped that the board will meet the printing requirements. However, as recently Zang and Aspler set forth above, but also continue to investigate factors of evenness. The higher grammage and opacity of the coloured liner board limits our ability to determine the uniformity. Further, a single-layer structure linerboard In general, therefore, the relative importance of the topsheet and backsheet formation and which measures, need to be still in research. The compressive strength of the carton from the top layer to the bottom layer is another important property that depends on the intrinsic compressibility of the surfacing and intermediate layer components. We found that, when absorbed decreased, short pitch variation rate is a significant increase in compressive strength.
 affect the evenness of the nature of the paper, especially a brief discussion in terms of the measuring machine, the work program of the American Forest & Paper Institute and assisted in funding measure to support the Technical Committee were reviewed. While improving the wet end to improve the function and do exciting development.
î—¥ î—¥ A paper web delivery system used in conjunction with an online leveling instrument was reviewed. When measuring toilet paper, newsprint paper, offset paper, and paper bag paper, the linear scanning measurement and the regional scanning measurement results were basically the same. The online uniformity measurement instrument was used to measure the visual homogeneity, but the data obtained was quite reasonable. The difference.
î—¥ î—¥ We expect to know what other sensors and formation analyzers will be used to measure the degree of formation in the future. Both strength properties and adaptability depend on the quality of the formation.