Solutions to common paper defects of corrugated board

　　1、 Broken pressing line

　　1. The inner paper is broken

　　Cause analysis: ① the inner paper is too thin; ② the inner paper is seriously dehydrated without toughness; ③ the groove angle of the pressing cam is not smooth; ④ the indentation is too deep.

　　The solutions are as follows: ① replace the inner paper or reduce the indentation depth properly; ② the inner paper may not pass through the preheater; ③ replace the arc line pressing wheel or polish the cam edge angle smoothly; ④ adjust the line pressing depth appropriately.

　　2. The tissue is broken

　　Cause analysis: ① the quality of the face paper is inferior; ② the indentation line is too deep; ③ the indentation concave wheel is too deep and not smooth; ④ the adjustment device of the indentation line fails; ⑤ the paperboard is too deep.

　　The solutions are as follows: ① spray steam on the surface paper, increase the glue amount and increase the drying speed properly; ② adjust the pressing line shallowly; ③ replace the indentation concave wheel or polish; ④ modify the pressing line adjusting device and then reproduce; ⑤ increase the drying speed properly and turn off some heat sources of the dryer.

　　3. The paper inside is broken

　　Cause analysis: ① the indentation is too deep; ② the paperboard is flat; ③ the paper has no toughness.

　　The solutions are as follows: 1. Adjust the pressure line shallowly; 2. Increase the drying speed of the locomotive; 3. Replace the tile paper or spray steam on it.

　　2、 Indentation crease uneven and uneven depth

　　Cause analysis: ① the pressing line is too shallow; ② the adjusting device of the pressing line is out of order; ③ the pressing wheel is deformed; ④ the pressing cam is seriously worn, and the wear degree is not considered in the production, so the normal operation is still carried out.

　　The solutions are as follows: 1. Adjust the depth of the pressing line until the inner paper is not broken and the pressing line is clear and straight after folding; 2. Correct and maintain the adjusting device of the pressing line to normal; 3. Replace the pressing wheel; 4. Adjust the depth according to the degree of pressing line.

　　3、 Breaking of tissue after folding

　　Cause analysis: ① the quality of facial paper is inferior; ② the drying speed is too slow, the cardboard dehydrates seriously, and the facial paper loses its toughness.

　　Solution analysis: ① change the face paper; ② improve the drying speed.

　　4、 Fracture of paperboard after forming

　　Cause analysis: ① the corrugated paper is too small; ② the paperboard is too dry; ③ the molding process equipment is not adjusted properly; ④ the pressing line is too shallow, the corrugated is not flattened or when the corrugated is folded after molding, the high-strength corrugated will break the face paper and the corrugated will break.

　　Solutions: ① replace the tile paper; ② ensure that the moisture content of the paperboard is about 10 ± 3; ③ pay attention to the adjustment of the equipment in each forming process and adjust it to the minimum state; ④ accelerate the dryer and increase the amount of glue, and adjust the depth of the line.

　　5、 Slitting burr

　　Cause analysis: ① the paper dividing knife is blunt or the blade is notched; ② the upper and lower knives bite too deeply; ③ there is a gap between the upper and lower knives.

　　The solution: ① polish or replace the new knife; ② adjust the coincidence of upper and lower knives to the minimum state; ③ close the upper and lower knives and turn the knife wheel by hand to be flexible without damaging the knife.

　　6、 Cross cut paperboard tailing

　　Cause analysis: ① the cross cutting knife is blunt; ② the upper and lower pieces of the cross cutting knife are not occluded properly, and the continuous cutting parts of the paperboard bring tearing surface tile paper under the action of mechanical force; ③ improper instantaneous acceleration adjustment of the cross cutting machine causes paper blocking.

　　Solutions: ① change the cutter and grind it; ② correct the position of the next two cutters; ③ adjust the instantaneous acceleration correctly according to the length of the paperboard.

　　7、 Paperboard softening

　　Cause analysis: ① the content of NaOH in glue is too high; ② the stacking overlap of offline paperboard is too high, and the water vapor in paperboard is not fully distributed; ③ the temperature and humidity of paperboard storage environment is too high; ④ the temperature of dryer is lower than 180 ℃ and the speed is too fast, and the low temperature environment causes the drying illusion, and the corrugated becomes soft after stacking, which reduces the strength of paperboard.

　　The solutions are as follows: 1) adjust the alkali consumption of glue properly; 2) adopt well shaped stacking, the stacking height should not exceed 1.5m; if necessary, use air blower for forced ventilation to disperse the water vapor in the paperboard; 3) open windows to cool the warehouse where the paperboard is stored, and remove lime powder to absorb moisture from the site; 4) flexibly control the car according to the glue application amount, paper and dryer temperature, while ensuring the quality of the paperboard Speed.

　　8、 Edge opening of paperboard

　　1. Glue opening at the edge of inner paper

　　Cause analysis: ① the belt of glue roller is not in place; ② the vibration of glue disk is free; ③ the temperature at both ends of tile roller of single side machine is insufficient or too high. After the instant gluing, the low temperature makes the glue liquid not gelatinized, and the water quickly penetrates into the corrugated paper, leaving starch imprint. After the gluing at high temperature, the glue quickly loses its stickiness.

　　The solutions are as follows: 1. Properly open the glue valve to increase the glue flow; 2. Correct the fixed glue disk; 3. Increase the temperature of the corrugating roller, and the water drops should evaporate in two or three seconds when the fingers dip water on the roller. If the temperature is too high, you can use a brush to dip oil on both ends of the tile roller, and the evaporated oil fume will take away part of the corrugated heat, so as to achieve the purpose of cooling.

　　2. Edge opening

　　Cause analysis: ① the glue on the coating roller is not in place; ② the conveyor belt of the dryer deviates and the edge of the paperboard is not pressed in place; ③ the temperature of the hot plate on both sides of the dryer is insufficient.

　　Solutions: ① make up the glue in the glue box to make all the glue rollers soak in the glue; ② correct the deviation in time to make the conveyor belt in place correctly; ③ start the machine after the temperature of the hot plate of the dryer is stable.