Good paper roll quality is a necessary condition for further processing. In the winding process of board paper, due to the uneven tension of the paper roll, defective roll paper equipment, and improper operation, all kinds of shapes may appear in the paper roll or die. The pleats are due to the following aspects:
First, the thickness, moisture, and evenness of the paper roll in and out of the reel are inconsistent, resulting in inconsistent stress on the various parts of the paper web inside the paper roll. When the paper web is uneven and the paper roll is rolled to a certain diameter, the paper roll will have a phenomenon of full elasticity. When the hand roll is used to turn the paper roll, the tight part will feel hard and the measured thickness will be relatively large; The loosely wound part is relatively soft and the paper is thin. When the difference between the soft and hard parts of the adjacent parts of the paper roll reaches a certain degree, oblique live pleats are generated on the soft parts, and new pleats are easily generated in the part where the local moisture is large in the paper roll.
Solution: (1) Adjust and control the technical conditions of the network department, copy and create a uniform wet tissue with good fibrous structure. (2) Choose the proper mid-height of the press roll and idler, and maintain each roll surface so that the wet paper web is uniformly dehydrated at the couch roll, the press roll and the idler roll, and evenly dried on the dryer cylinder. (iii) Flexible use of the adjustment handwheel on the roll holder to adjust and raise or lower one end of the paper web in the reel cylinder operation to reduce or eliminate lint from the roll paper operation. One way to do this is to raise one side of the paper roll, and then this side of the paper roll is rolled loose; lowering one side of the paper roll, the side of the paper roll is rolled tighter. On narrow paper machines, a handwheel can be adjusted on the operating side. The second is that when hemp-like live folds appear on the paper roll, the hand wheel is adjusted according to the feeling of the palm and the direction in which the living folds are tilted, ie, which side of the wave pattern is inclined, the hand wheel is used to lower the paper roll. Side; If one side of the wave pattern is low, then raise this side of the paper roll with the hand wheel. Thirdly, the side of the paper roll is relatively hard, so that live pleats appear in the inner part adjacent to the hard part. If the width of the live pleat is narrow, use the adjustment hand wheel to lower the side of the paper roll. The purpose is to put the paper. On the roll, the harder and softer part of the roll is pressed against the cylinder surface of the reel. If the range of the living pleat is wide, raise this side so that this side of the paper roll is rolled loosely, or press The above method handles. (4) When there are live pleats, the tighter the roll of paper is, the more severe the pleats are, so the tension of the web between the roll and the dryer should not be too great. The tension of the small diameter paper roll should not be too large. The tension of the small diameter paper roll should not be too large. (5) Play the role of the front arched roll of the reel, that is, use the arched roll in front of the reel to locally adjust the unevenness of the web tension. Under the premise of not impeding the operation of the paper roll, the position of the arched roller is appropriately close to the paper roll cylinder and the installation is lower, so that the area of ​​the paper clad cylinder face is larger, and the arched roller pair flattens the paper web and prevents the paper wrinkle. The role will be better. (6) In the normal operation, some loosely wound paper is wound into the soft part of the paper roll, or a certain length of paper is torn off in the hard part of the paper roll to make the paper roll tight and uniform. Reduce living folds. (7) When the paper roll is bouncing on the surface of the cylinder due to severe uneven softness and hardness, when the folds are pressed into dead folds, immediately replace the roll.
Second, the degree of parallelism, horizontality, and verticality of the roll holder are not properly calibrated, the tilt angle is not stable, the position of the roll paper roll is not placed properly, and the width of the full roll of the paper roll on the roll paper cylinder is too different before and after the two ends. The tension on the paper web entering the take-up roll is inconsistent, and the skewed paper web is curled diagonally at the end where the paper roll makes contact with the cylinder surface. On large-diameter paper rolls, the large and often lively folds are often rolled up. On the small paper roll that is just on the machine, it will be pressed into folded folds.
The solution is: First, use the adjusting handwheel on the roll holder to lower the high side of the paper roll so that the paper roll and the cylinder surface are in full contact. While adjusting, observe the tension on both sides of the web until the web enters the winder. Secondly, the parallelism, levelness, verticality and inclination of the roll holder are corrected so that the equipment meets the technical requirements.
3. The diameter of the roll of paper roll and the diameter of the shaft head are too small or bent, and the pressure at the two ends of the roll paper shaft is too light. The pressure at both ends is inconsistent, which causes the tension of the paper in the paper web to be inconsistent and the runout of the paper roll to run, resulting in buckling. .
The solution is: (1) When processing roll paper rolls with large roll diameters and shaft head diameters, the paper machine with a typical paper width of 1092 mm should have a weight of not less than 55 kg and a diameter of not less than 125 mm; A 1575 mm paper machine with a web width of not less than 80 kg and a diameter of not less than 150 mm. The roll paper roll is mostly processed by iron pipe or casting. The surface should be round and smooth, and it should have good contact with the surface of the dryer. This can reduce the runout of the paper roll when it is first rolled. And pay attention to maintain roll paper roll. (2) Select the appropriate weight of the pressure, and hang it on both ends of the roll paper shaft when renewing the paper roll, and keep the two ends of the paper shaft under pressure. (3) If the roll paper roll is not straight or thin, it can leave a layer of paper about 50 mm thick on the roll, and it should not be cut off and left as the bottom layer of the next roll paper, which can reduce the roll core paper loss.
Fourth, when the sheet breaks, if the uneven soft and hard paper rolls are idling on the reel cylinder, the time is slightly longer to easily press the certain thickness of the paper roll on the surface of the paper roll into many pleats, so it is best to break the head. Leave the roll off the cylinder surface. When guiding the paper web to the paper roll, pay attention to aligning the tail of the paper roll that has been wound on the paper roll. Do not allow a large number of uneven paper tails to be caught in the paper roll. Otherwise, the surface of the paper roll will be uneven. The good paper on the paper roll is pressed with pleats. When the tip of the paper continues to roll on the paper roll, it is also necessary to level the paper as much as possible, not to mess up the head into the paper roll, so as to avoid causing a lot of pleats. When sampling at the tear edge, it is not appropriate to obtain too deep or too much, otherwise it will produce a large number of pleats.
Fifth, when changing the paper roll, in order to make the newly replaced roll paper roll and the surface of the paper roll cylinder closely, in addition to the steel wire rope hook at the two ends of the roll paper roll to increase the weight, and use a hand roller to help tighten the paper roll. . Some operators also temporarily stop the fan in the exhaust hood of the dryer when changing the paper roll, increasing the moisture content of the paper sheet, and turning on the fan immediately after the paper roll is on the roll. This operation is fast and the effect is also good. Some operators sprayed water on the iron roll while changing the paper roll. This solved the problem that the paper and the iron roll were not sticky, but it caused the wrinkles of the roll bottom paper to be wet due to the water spray. as a result of.
Sixth, the paper width is relatively wide, quantitative small paper, some machines in the network part of the water from the middle of the paper is divided into two, so that the paper width is narrowed, or add a small roller in the roll before the roll, pick the paper From the cylinder surface and then into the roll, both can receive good results.
From the above analysis, it can be seen that there are many reasons for the occurrence of pleats on the reel paperboard. It is necessary to conduct specific investigation and analysis, take measures, and solve them to ensure the quality of the finished product.
Excerpted from China Packaging Yearbook 1999