Cardboard Flatness Best Solution--Board Warping Detailed (5)

How to more evenly control glue changes

The main cause of the warpage of the corrugated board is the unbalanced moisture content in the single-sided paper and the double-sided bottom paper in the formed cardboard. In order to produce a straight corrugated paperboard, it is necessary to control the moisture content of the noodles and the use of glue adhesives. How to ensure that the non-uniform paste to cardboard warping and bonding process to minimize the. The factors that may affect the “smoothing” of the adhesive on the paste roller and the “transfer” of the adhesive from the paste roller to the tip of the corrugated core paperboard.

Glue Variable

â–  The cleaning and parallel mechanism of the squeegee/paste roller;
â–  Rubber roller adjustment mechanism;
â–  The efficiency of the rubber roller scraping film;
â–  Eccentric rotation of the paste roller and the squeegee roller â–  The mechanical state of the paste roller and the squeegee roller (wear scars);
â– The state of the bearing of the paste roller and the squeegee roller â– The ratio of the speed of the squeegee/paste roller, that is, the percentage between the rotation speed of the squeegee roller and the rotation speed of the paste roller;
â–  Corrugated board production line production speed;
â–  Adhesives - Formulations, temperatures, flow rates, etc.

Adhesive transfer on core paper

Single-sided machine

â–  Paste - The base paper speed, that is, the percentage between the rotation speed of the paste roller and the speed of the single-sided paper web. â–  The cleaning and parallel mechanism of the paste roller and the lower position corrugating roller;
â–  Cleaning of the guide/lower position corrugating roller - "Individual adjustments of the guide and the guide bar in parallel with the lower position corrugating roller;
â– Eccentric rotation of the paste roller and the lower corrugating roller â– The mechanical state of the paste roller and the lower corrugating roller â– The bearing state of the upper corrugating roller and the lower corrugating roller;
â–  Core paper - a height, surface roughness, surface pores, flexibility (dehydration);
â–  Corrugated board production line production speed;
â–  adhesive one by one formula, temperature, flow and so on.

Double-sided machine--gluing machine

â–  Paste roller speed â–  Cleaning (pressure) and parallel mechanism of the paper guide roller/paste roller;
â–  The mechanical state of the paste roller and the paper guide roller (wear, dirty);
â–  Eccentric rotation of paste roller and paper guide roller;
â–  The type of paste roller (smooth or concave surface);
â–  paste roller temperature - peripheral heating or internal heating;
■Single-side paper web leading to or leaving the paste roller ■One-for-one corrugating of core paper, 楞 profile or shape, “楞 shape” hardness, single-side paper height, core paper stretchability (dehydration);
Corrugated cardboard production line production speed:
â–  Adhesives - Formulas, temperatures, flow rates, etc.

How to avoid the above problems. At the same time to understand and solve, in the state of keeping the rollers in parallel and the scraper working normally, affecting the use of adhesives, resulting in the key factors causing cardboard warp.

speed

Cone-driven machines on single-sided machines will increase the amount of “extruded” paste on the paste rollers and tip at low speeds in corrugated board production lines, reducing paste usage during high-speed production. The amount of adhesive used decreases with increasing speed, and when the speed of the corrugated cardboard line becomes slow, the results are not consistent depending on the situation. The use of a fixed-rate roller on a single-sided machine, that is, according to the production speed of the corrugated board production line, the paste roller operates correspondingly at the same speed. As the speed increases, some manufacturers will supply more adhesives to prevent the quality of the cardboard from deteriorating when the speed of the machine is slowed down. This actually results in the waste of adhesive and the tendency of the board to warp (normally warp) during high speed production.

Glue gap

The only way to control the amount of adhesive used by the operator of the corrugated board production line is to change the glue gap. The glue gap adjustment is very important. Any operation in the operation of the machine will cause changes in the glue gap that are not known to the operator and must be observed at any time for adjustment. It is recommended to always maintain a certain amount of glue to ensure timely supply. In this way, the influence of mechanical operation on the paste supply can be avoided. The long-term operation of the machine will cause cumulative error, and the display data is not necessarily correct. Correctly, the gap of the glue should be corrected regularly with a feeler gauge, and the necessary adjustments should be made to ensure that the paste gap remains consistent at all times.

scraper

Scrapers act like "dams" in single-sided machines. As the scraper rubs against the exposed dry metal surface outside the "dam" end position. When the blade wears, the operator has to tighten the blade to prevent the glue from leaking from the blade. However, it is still impossible to avoid the increase of gaps in the paste and the increase in the amount of adhesive. A "broom" type scraper can increase the amount of adhesive used, transfer from the adhesive solution under the blade of the blade to the paste roll, and is then transferred to the core paper. As the speed increases, the amount of glue that drips under the leaves also increases. Causes waste of adhesive and warpage of the board. If it occurs at a single-sided machine, the board shows normal (upward) warping. If it occurs at the double-sided machine, the cardboard in the stacking at the end of the corrugated board line is warped (downward). The problem of "smashing" scrapers is easy to solve. A reversed angle rubber blade made of phosphor bronze can be installed. This blade uses a small amount of pressure to scrape the adhesive from the squeegee, and the adhesive on the squeegee on the single-faced machine is not affected by the drying out. This has the advantage of reducing, especially in certain cases. Adhesive consumption in the position or corrugation direction and warpage of the board.

(to be continued)

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