Three, warpage
1. Warpage is divided into: horizontal downward warping, horizontal upward warping, longitudinal upward warping, longitudinal downward warping, S-shaped warping, two-way warping
2. The hazards caused by warping:
① After the corrugated board machine is cut, the paper cannot be automatically coded, that is, the automatic stacking machine cannot be used and the stacking needs to be manually reversed, which is time-consuming and labor-intensive.
②The compressive strength of corrugated cardboard is reduced.
③It is difficult to manufacture when used in slotting and printing machine, and it is easy to produce defective products.
④Cause the dimensional accuracy is reduced, and the degree of automation is reduced.
⑤ Increase work efficiency and loss.
(1) Horizontal downward warping
performance is: in the transverse cutting direction, there is a downward bending trend.
Cause: Solution:
①The amount of glue applied by the applicator is too small ① Increase the amount of glue applied by the applicator appropriately
②The temperature of the hot plate of the double-sided machine is not enough. ②Increase the temperature of the hot plate
③The water content of the single-sided corrugated board of the paper flyover is not enough. ③Appropriately increase the moisture and accumulation of the paper flyover board to maintain moisture (depending on the climate at the time)
④Excessive heating of the triple preheater ④Reduce the preheating angle
⑤The amount of glue applied by the single-sided machine is too small. ⑤ Increase the amount of glue applied by the single-sided machine
⑥ The speed is too fast ⑥ Reduce the speed appropriately
⑦The running tension of single-faced corrugated board is not enough. ⑦Adjust the tension control system to increase the resistance
⑧The moisture content of the B machine or the surface paper is too high. ⑧Reduce the moisture content of the B machine tile paper or the core paper and reduce the speed of the car
⑨The tension of the preheated water for the board of the single-sided machine is inconsistent with the tension of the preheated water for the panel of the double-sided machine. ⑨Adjust the system to make the moisture content and tension consistent
(2) Lateral upward warping
The performance is the same as above, and the direction is upward.
Cause: Solution:
①The preheating wrap angle of the panel is too large. ①Reduce the wrap angle and reduce the preheating
②The preheating wrap angle of the inner paper is too small. ②Increase the wrap angle and strengthen the preheating
③Excessive accumulation of paper flyover ③Reduce accumulation of paper flyover
④The amount of glue applied by the single-sided machine is too large. ④ Control the amount of glue applied by the single-sided machine appropriately
⑤The amount of glue applied by the glue applicator is too small. ⑤ Increase the amount of glue applied by the glue applicator appropriately
⑥ The vehicle speed is too low ⑥ Increase the vehicle speed appropriately according to the actual situation and operating quality
⑦The temperature of the hot plate of the double-sided machine is too high ⑦Increase the speed of the car or artificially reduce the low temperature
⑧ Excessive pressure applied by the weight roller ⑧ Put the weight roller appropriately
(3) Longitudinal upward warping
The performance is: in the direction of cardboard manufacturing, there is a downward bending trend.
Cause: Solution:
①Insufficient strength of the original paper ① Increase the control of the tension system appropriately
②Unbalanced moisture content of the base paper ②Preheat properly or after spraying water
③The preheater wrap angle adjustment is unbalanced ③Check and repair the transmission device to ensure parallel operation
④Excessive accumulation of paper flyover (A machine) ④Reduce accumulation
⑤Excessive tension of corrugated cardboard output from the paper flyover (A machine) ⑤Appropriately reduce tension control
(4) Longitudinal downward warping
Cause: Solution:
①The running pressure of the canvas belt is not enough ①Check and correct the tension of the canvas belt
②The tension of the corrugated cardboard output by the paper flyover is not enough ②Appropriately increase the output tension control
③Unbalanced moisture content of facial tissue ③Spray water and properly preheat
④The paper has too much force ④Reduce the tension control of the paper
(5) Two-way warpage
Cause: Solution:
①Unbalanced moisture distribution in base paper ①Spray or preheat control
②The transverse tension of the canvas belt is not balanced. ②Keep clean and dry, and adjust the tension system appropriately
③The force of the original paper in the inside and the surface is too large or too small ③Tighten or release the brake to control the tension
④The floating roller of the preheater does not work properly ④Check or correct some parts in operation to ensure horizontal operation
⑤The center line of the paper flyover, preheater, and gluing machine is not allowed to be incorrect. ⑤Re-correct part of the deflection to adjust
Fourth, the phenomenon of washboard (through flute)
performance is: the surface of the corrugated cardboard, especially the liner board (face paper) on the supporting side, has unevenness. Like the washboard, it is called the “washboard phenomenon”, which is also often said: “through corrugated.” It can be seen that the corrugated peaks of the washboard-like corrugated base paper protrude and form a bone state. Not only the appearance is not good, but also the cause of the printing blur during the box making. In order to prevent the printing from blurring, the printing pressure must be increased, which results in the cardboard. Deformation, the compressive strength of the carton decreases. The mechanism is as follows: apply too much adhesive on the corrugated peak of the single-sided corrugated board. Due to the pressure of the pressure roller on the gluing machine, the excess adhesive is squeezed to the two sides outside the corrugated peak, and the adhesive starts The role of fixed direction, but the adhesive shrinks when it dries. Excessive adhesive means excessive moisture. The faceplate paper absorbs excessive moisture and stretches, and the stretched part is gelatinized by the adhesive and the single-faced corrugated paper cannot shrink, resulting in a “washboard” phenomenon. .
Cause: Solution:
①Too much adhesive ①Reduce the amount of adhesive applied
②The water ratio of the binder is too large. ②Adjust the water ratio to reduce the amount of water.
③The line pressure of the glue spreader is too large, and the gap is too small. ③Adjust the glue spreader gap between the float rollers of the glue spreader
④The corrugated roller is seriously worn out. ④Replace the corrugated roller
⑤The paper has a large water absorption capacity. ⑤Adjust the paper and use a paper with low water absorption.
⑥Unreasonable adhesive compounding ratio ⑥Change the formula and change the adhesive ingredient ratio
V. Jumping (jumping the pit)
performance is: poor corrugated forming height is uneven, corrugated base paper does not form a normal corrugated part of the deformation is called skipping; it is also called skipping pits in the industry. This phenomenon only occurs on single-sided corrugated cardboard.
Cause: Solution:
①The moisture of the corrugated base paper is too large or too small. ①The moisture is too large, increase the preheating area, and use steam to humidify when it is too small
②The braking force of the corrugated brake is inappropriate (too large or too small) ②Adjust the friction force of the brake to make it reach a suitable state
③When the pressure of the corrugated roller is insufficient or uneven, ③Adjust the pressure of the corrugated roller to make it suitable
④The corrugated roller is dirty or damaged or the bearings are worn out. ④replace or clean the dirty parts or parts
Post time: Jul-08-2021