This article comes from a siege lion who has worked in the paper workshop for many years. It may be summarized by himself or recorded by others in the process of work and learning. Anyway, it will be a good reference for young people who are still exploring in practice. Thank him! His name is.....，Sorry, it's confidential. He himself is very low-key and doesn't want to be exposed. Ha ha

1）If the dewatering capacity of the forming mesh allows, reduce the concentration of the headbox；

2）If other aspects of paper quality permit：

Change the paper material to shorter fibers (for coated base paper or double offset paper, use more hardwood; For wood pulp paper, reduce the freeness of wood pulp or increase the quantity of wood pulp); If appropriate, increase beating;

3）Operate under the most ideal mesh tension (do not let the forming mesh hang on the dewatering element or be too loose at the chest roll; Do not let the mesh change direction violently in the forming plate and table roll area)

4）Improve the dewatering capacity of the net case in the following ways：

a）Move the vacuum box towards the couch roll and add more dehydration elements

b）Add board or preferably humidify vacuum box

c）Install a vacuum box with low friction coefficient (in this way, the forming mesh can run in a tighter way on the chest roll, and the former part of the mesh can give full play to the dehydration effect in addition to dehydration in the vacuum box)

d）If the stability of the slurry on the forming net permits, the angle of the cutting board can be improved and the vacuum degree of the wet empty box can be improved

e）Reduce initial dehydration to prevent net pasting

5）The setting of forming mesh can be improved in the following ways：

a）Correctly set the distance between the previous roller and the wiper plate so that there is no large water flow between them

b）All the wiper plates are properly positioned on the forming mesh, so that no water flows through the wiper plate

c）Confirm that all dewatering elements are aligned (the cutting board shall make its tip contact with the forming net correctly; All cutting boards shall have the same wear)

d）All rollers rotate freely

6）For the existing headbox, the optimal quantitative distribution is always maintained

7）The slurry discharge at the lip shall be as consistent and uniform as possible (flocculation shall be avoided as far as possible)

8）Set the pulp net speed ratio to the best state (in fact, use the instrument to read the value; (for advanced paper machines, this value is automatically controlled)

9）The following conditions are better (upper lip, lower lip, forming plate, chest roller, landing dot, avoiding backflow of forming plate, avoiding material rejection of chest roller and massive dehydration of chest roller)

10）Under special circumstances, it is advantageous for the chest roller to dehydrate, and 15 ~ 20% of the slurry falls at the chest roller (when the headbox is not well distributed, it is advantageous for the landing dot to move back)

11）Avoid slurry jumping of the forming plate (the front end of the forming plate shall be lower; Increase the vehicle speed by 1000m and reduce it by 5mm, so that a rapid upward acceleration can be avoided when surfing the Internet)

12）The impact of slurry on the net shall not bring destructive effect

13）Check the homogenizing roller

a）Ensure that the design of the homogenizing roller does not cause flocculation due to the aggregation of fibers under the headbox

b) Avoid slurry hanging on the homogenizing roll

c) Lip, homogenizing roll, do the following experiments

___ Keep the opening rate of 48%, and the aperture should be as small as possible under the condition of slurry permission

___ If the reason for poor forming is that the hole is too small, increase the hole (the thickness of the roll should also be increased)

___ For the slurry with long fiber and average concentration of 0.4 ~ 0.6%, the opening rate is changed to 43 ~ 44% to obtain the blind surface with sufficient area and the hole size required by the fiber type

___ Ensure that the end design and shoulder of the homogenizing roller do not affect the edge of the web slurry

___ Check that the interleaving of the solid parts of the homogenizing roller will not cause paper streaks

14）Confirm that there is enough micro turbulence on the net, especially in the sheet forming stage (this can ensure proper flocculation and better forming)

15）Delaying dehydration by removing one or more dehydration elements will destroy the forming

16）There is always a middle point between dewatering speed and forming

17）The operation of finishing roller (3 ~ 5m faster than the mesh speed); Special requirements for high-speed rollers; Rotate when not in use; (one spare)

18）If the shaking device is used and the shaking speed cannot meet the effective requirements:

a）Increase the shaking energy (the effectiveness of shaking is basically proportional to the square sum amplitude of vibration times; (the limitation of the mechanical structure of the forming part shall be considered)

b）If the structure of the forming part is suitable for low-speed paper machine, the shaking can be further extended to the back of the net with a cross bar, and good results can be achieved

19）Quantify the forming effect with the forming detector (ensure that there is no excessive forming change in the transverse quantification)

20）When speed forming is used, the angle of the first chopping board is slightly smaller to improve the retention rate of the first pass and reduce the dehydration capacity at this point (if forming is too fast, the angle of the chopping board needs to be increased to improve the role of the mesh)

21）A shaped nozzle is considered to improve the turbulence at the initial stage of dehydration

22）If the wet end chemicals cause flocculation, the activity and beating of the online slurry will be more necessary (better is to improve the addition of wet end chemicals)