Cardboard Flatness Best Solution--Board Warping Detailed (6)

Single machine wear

Abraded paste roller and eccentrically rotating single-sided machine. The most used adhesive is the edge of the worn paste roller. The end of the paste roller is corroded and damaged over a long period of use, so that the diameter becomes smaller and the gap at both ends increases. Another, more expensive place is caused by the eccentric rotation of the rollers. The gripper between the paste roller and the squeegee roller changes with the rotation of the roller, that is, the rotation of the roller is eccentric. The ratio of the binder in the parallel direction of the machine is 3 to 1. Eccentric rotation problems commonly occur in adhesive paste systems. Damage to the winding device around the lower corrugating roll often results in eccentric rotation problems on the single sided machine, causing the board to warp. Thermal distortion on a single-sided paste roller can also result in biased rotation. If the distance between the paste roller and the lower corrugating roller is too close under heat, the paste roller will stop rotating, and the paste roller will bend and be in the same position. Corrugated roller contact occurs. A broken rubber roller can then cause damage to the squeegee. Even without damage, the squeegee does not uniformly clean the damaged roller surface. In order to prevent the damage caused by the contact between the paste roller and the lower corrugating roller, a stopper for the rubber roller needs to be installed. If the stopping device is deactivated or out of control, the squeegee roller may hit the squeegee roller and cause the metal surface to wear at the ports of both, resulting in an excessive amount of paste.

Other adjustments

The use of a uniform adhesive on a single sided paper requires that all the rollers are in good working condition, parallel to each other and in the correct position, the arrangement of the guide jaws is evenly distributed across the width of the machine, and the adjustment is properly adjusted. The tip on the roll removes all of the adhesive from the paste roll gap.

Worn paste roller or rubber roller bearings will have an impact on the use of adhesives. At a certain speed, the adhesive film on the paste roller will appear alternately bright and dark. Paste gaps increase as speed increases, which in turn can damage the bearings. The damaged bearing slightly separates the squeegee and paste rollers due to the hydrodynamic forces generated at the measurement interface during acceleration. When the corrugated board production line is stopped or at normal speed, feeler gaps are detected using a feeler gauge on the operating side, center and drive side. If the change in the gap exceeds the specified value, the bearings of the paste roller and the squeegee roller are worn or an unknown object is present between the two types of rollers.

The cleaning degree of the guide jaw and the lower position corrugating roller must be the same to ensure that the adhesive can be evenly distributed in the lateral direction of the single-sided machine.

The tip on the cleaning roller can also affect the use of adhesives. Most single-sided machines are equipped with self-cleaning telescopic equipment. In most cases, when the speed of a corrugated board production line increases rapidly, this effect decreases. You can lower the speed of the tip or stop it completely when it is indented.

The amount of adhesive on the double-sided machine varies with the speed ratio of the paste-base paper, the floating roller pressure, and the type of paste roller surface that is smooth or concave.

The heating of the paste roller also affects the use of adhesive on the double sided machine. The adhesive paste used in the paste with a higher temperature than the surrounding environment has a large amount of adhesive.

The influence of the moisture content of the core paper on the amount of binder in the single-faced machine has found that the core paper region with low moisture content has more binder than the core region with high moisture content.

The glue sticking dose is related to a large number of fluctuations. Changes in the paste gap will cause the adhesive used in the corrugated board production line to multiply. In order to ensure that the amount of a specific binder is used, periodically detecting the amount of the binder and adjusting the gap of the paste can effectively improve the amount of the binder.

It is no easy task to maintain the adhesive application system in good condition. The damaged winding device that surrounds the lower corrugating roll will cause a new paste roll to bend and rub off the entire set of paste forks. Efforts must be made to design paste rollers and squeegee mechanisms that do not accidentally become damaged due to the winding device (as on the paste unit), and to ensure that there is no damage under pressure and that the production of the single facer is automatically stopped.

Each corrugated board production line has a different paste roller/rubber speed ratio. At different corrugated board line speeds, only the amount of binder sizing is affected. In addition, different binder formulations differ in performance or "uniformity."

Measure

Measures that can be taken to improve the uniformity of adhesives in existing corrugated board production lines:

â–  Keep the adhesive application system in a good mechanical condition;
â–  Install a reverse wound detector on a single-sided machine to avoid damage to the squeegee and paste rollers;
â–  Replace the damaged paste and squeegee rollers â–  If the squeegee does not evenly clean the squeegee roller, identify the cause and replace it with one of the previously recommended methods. â–  Verify that the cam drive on the single-sided paste roller is in good condition. Unless the paste roller is rotating, do not let the paste roller close to the lower corrugated roller;
â–  The single-side machine with a fixed speed ratio paste roller turning device will have more adhesives applied as the speed increases. If this creates a problem with glue or paper warp, install a quick-acting paste roller drive;
â–  Install adhesive consumption system on single-sided machine and paste dispenser. In order to complete the full adhesion of the board, the glue gap is adjusted to ensure the specific amount of adhesive.

Cardboard warpage is one of the important issues affecting the quality of paperboard. It is caused by a variety of factors. We must grasp the reasons for the formation, find solutions, try to avoid board warpage, reduce paperboard wear, and produce high-quality corrugated board.

----"Cardboard Manufacturing Process Solutions" June 2005