Classification of " press felt marks":
"press felt marks" actually contain two kinds of marks: one is the marks caused by the base cloth of the press felt, called "base cloth marks"; the other is caused by the rough surface of the press felt, the needle punch marks, and the thick fibers. There are rough marks on the surface of the paper, which are called "feather marks on the press felt".
Causes of press felt marks:
The organization structure of the base fabric (bottom felt) of the papermaking felt is improperly selected or designed.
The structure ratio of the papermaking felt is unreasonable, that is, the fiber layer of the felt, especially the fiber layer on the front of the felt, is too small.
The warp tension and beating force during the weaving of the bottom cloth are too small, resulting in insufficient flatness of the woven bottom cloth.
The first finalization (predetermined type) of the bottom cloth does not work well.
On the side of the papermaking felt that is in contact with the paper sheet (the working surface of the felt, that is, the front side), the surface layer of fibers is too thick.
Due to the poor quality of felting needles, improper needle use, unreasonable needle board layout, and unreasonable needle punching process, the working surface of the felt leads to too heavy needle marks and dense, uneven pinhole marks.
The felt is uneven during the combing process, and "cloud flowers" of varying sizes appear.
The felt shaping still uses the traditional far-infrared shaping equipment. This type of shaping equipment uses high temperature radiation to melt the fibers (fiber bundles) on the felt surface into colloidal particles during the felt shaping process. It cannot be pressed (grinded) for a long time during use.