In the pressing process, if the process is not appropriate, problems such as longitudinal breakage of the cardboard, non double folding, etc. may occur. The following text will summarize the causes of the problem and provide solutions. It should be noted that even after taking corresponding measures, it is still necessary to require operators to conduct necessary and regular spot checks during normal operation, in order to timely detect defective cardboard and take timely measures.
one
The cause of longitudinal fracture
(1) The vertical rolling pressure is too high.
When the cardboard enters the pressing wheel operation, the pressing wheel crushes the cardboard, causing the inner or outer paper of the cardboard to break in the direction of the corrugation. To solve this problem, the operator needs to adjust the pressure of the vertical line pressing wheel according to the thickness of the cardboard. Under normal circumstances, the rolling depth of the three-layer cardboard should be 2mm to 3mm when the pressing wheel presses into the cardboard. However, during normal production, the operator needs to adjust the pressure based on the quality of the original paper, with the standard of not crushing or folding.
(2) The wire pressing wheel is unreasonable.
The most commonly used method in cardboard embossing is convex to concave. Due to differences in the use of paper, production environment factors, and thickness of cardboard, the structure of the wire pressing wheel used also varies. The main parameter is that the width of the upper and lower pressing wheels should be appropriate, and the transition arc of the step of the pressing wheel should be adjusted according to the depth of the pressing line and the applicable cardboard. Generally speaking, the thicker the cardboard, the wider the embossing width. For three-layer cardboard, the curved surface embossing wheel method can also be used. There is no unified structural form for the wire pressing wheel, and operators are required to find a suitable wire pressing wheel structure based on the actual situation.
terms of settlement:
(1) Improve the structure of the wire pressing wheel. Adjusting the structure of the wire pressing wheel can appropriately increase the radius of the step transition arc of the wire pressing wheel.
(2) Adopt the method of pre compression failure and perform pre compression before the formal compression line. Its disadvantage is the formation of obvious pressure marks.
(3) The quality of the original paper is required, and for cardboard with higher requirements, high-quality surface paper and inner paper should be used.
(4) The moisture content of the base paper and cardboard should be appropriate. The worse the quality of the original paper, the drier the cardboard, and the higher the probability of line breakage.
(5) Properly control the depth of the pressure line. Control the gap between the upper and lower pressing wheels according to the thickness of the processed cardboard, so that the cardboard can receive appropriate pressing.
(6) Control the alignment of the centerline of the upper and lower wire pressing wheels to prevent misalignment of the wire pressing wheels.
(7) For cardboard with particularly poor original paper quality, a stitching machine is used for stitching.
(8) If the line breakage is caused by the drying of the cardboard, water spraying can be used to increase the moisture content of the cardboard.
two
The reason why reverse folding does not form a double line
Under normal circumstances, the indentation line manually operated by a wire press (also known as a wire collision machine) is folded in the direction of the face paper in a double line. The so-called non double line refers to the non straight folding line, and the indentation under two knives is not obvious or unbalanced, resulting in non double line. The reason is that the two knives are worn normally, and the pressure at both ends and in the middle is inconsistent, causing it; The second is that the lower convex bar is not centered, causing the indentation line to shift and form a reverse fold that does not form a double line; The third issue is that the equipment itself has not been properly adjusted, resulting in inconsistent pressure at both ends, with one side being larger and the other smaller, resulting in a non double line folding.
terms of settlement:
(1) According to the wear of the two knives, timely sharpening should be carried out to maintain balance between the two sides and the middle;
(2) Adjust the lower convex bar in a timely manner to ensure it is in a normal state according to the double line situation of the reverse folding;
(3) According to the operation of the equipment, please ask maintenance personnel or operating technicians to adjust the equipment to make it in the best condition.
