Discussion of Common Paperboard Problems

The development history of China's carton industry automation can be traced back to the 1980s. Prior to the 1970s, carton production equipment was manually operated and production efficiency was low. From the 1980s to the early 1990s, an era of single-plane units was formed. Cardboard produced by one-sided corrugated units has the disadvantages of soft material quality, poor quality, and large waste of base paper. By the mid-1990s, it had developed into an ordinary low-speed corrugated production line. In recent years, it has rapidly developed into high-speed and high-grade production lines. At present, the production methods of “centralized system manufacturing and decentralized system manufacturing” have been implemented in various localities. This has become the pattern of cooperative production of cardboard within the industry. Automated machinery has gradually replaced manual labor and has also accelerated market competition. The carton industry itself is a small profit industry, and some regions are still desperately engaged in the "price war" in the industry, which has caused the industry's profits to "shrink" to about 5%. Some are even less than 5%. With such fierce and cruel market competition, all companies can only tap into their own potential, reduce various management costs and costs, and, on the other hand, improve product quality, reduce losses, and enhance employee quality education to reduce waste product rates. And improve the yield as a point of profit growth. The quality of human resources varies from company to company, and most companies often experience cardboard quality problems in the production of paperboard, such as paperboard foaming, low board strength, cardboard warping, cardboard wrinkles, see-saw-like, bursting when pressing lines, The edges are not uniform, the cardboard is not well bonded, the thickness of the paperboard is not enough, the cardboard quality is high and low, and the paperboard is collapsed and dumped. Paperboard quality problems often cause business investors, managers and operators to “get savory or sleepy”. It is an annoyance and a headache for the company, which makes the production and development of the enterprise greatly constrained. How to improve the quality of the paperboard production line and solve the paperboard The quality issue is also an urgent and urgent problem to be solved by investors, managers and operators of various enterprises.

Explore and solve several common problems with cardboard quality.

Cardboard foaming

There are many reasons for the foaming of cardboard:

1. The tension of the corrugated paper and the core paper is not enough. Adjust the brakes so that the tension can be increased as much as possible without pulling the paper.

2, the temperature is not enough, the original paper contains too much water, glue is too thick, the speed is too fast; increase the preheating angle of the base paper, increase the temperature, so that the surface temperature not less than 160 °C, thinning the sizing amount or reduce the speed.

3, the thickness of the base paper is not uniform, low g paper when the wind suction slot blisters; speed sizing roller and the next corrugated distance.

4, corrugated roller and pressure roller wear serious, replacement and repair.

5, the wind suction is small, suction paper instability, check the pipe and 楞 Ci Cifan debris debris and debris removal, check the pressure roller at both ends of the graphite ring spring failure and make the seal is not good, external suction machine The suction hood is adjusted to the proper position. Low cardboard strength Cardboard production often has low board strength, very low force, and is relatively soft, often causing customer complaints and returns. The above reasons are often caused by the following aspects. The speed is fast, the sizing is too large, the humidity of the base paper is high, the quality problem of the glue manufacturing, the working surface temperature is low, the quality of the base paper is not sizing, the corrugating roller is used for too long, the wear is severe, the solution method is reduced, the speed is reduced, and the sizing roller is adjusted Increase the heated area of ​​corrugated paper to increase the wrap angle of the preheated cylinder and reduce the amount of caustic soda. If the amount of caustic soda during pulping is too high, the paperboard will easily absorb moisture and soften after bonding, increase the working surface temperature, and maintain the working temperature. In 160 °C ~ 180 °C, as much as possible to purchase raw paper sizing pit paper, increase the number of grams of corrugated paper, corrugated roller wear serious repair, replacement.

Bad cardboard adhesion

Commonly there are separation, blistering, false bonding, and weak bonding.

The main reason is

1. Adhesive quality problems, inconsistent ratio of raw to cooked pulp, more raw slurry, less cooked pulp, more water, lower powder ratio, and more borax, so that the gel is too fast or the adhesive cohesion is less, and the moisture is evaporated after being heated Causes blistering and separation. Less raw slurry, more mature pulp, less water, more powder, less borax, slower gelation, greater adhesive cohesion, poor penetration. The result is a surface bond that is essentially incompletely adherent and is often referred to as "false adhesion."

2. Fast speed, low temperature, large amount of sizing, large original paper or slow speed, high temperature, low sizing, and low base paper moisture, so it is necessary to adjust the preheating angle according to the moisture of the base paper, control the temperature and production speed. It is important to adjust the amount of suitable sizing.

3. Uniform amount of sizing, single-sided paperboard potholes are uneven, the sizing roller and pressure roller of the gluing machine are not parallel, the sizing roller and the homogenizer roller are not parallel, the upper and lower sizing rollers and the upper and lower homogenates are glued with dry glue. The surface is uneven and the pressure of the squeegee is not clean, which affects the uniform coating of the adhesive.

4. The parallel and distance between the pressure roller and the heating plate of the bonding machine, and the alignment between the pressure roller and the heating plate must be adjusted. The thickness of the paperboard is not enough to form the thickness of the paper board. The main reason is that the corrugated roll is not well adjusted, and the depth is not yet reached. The upper corrugated roll blank screw is opened. The eccentricity adjustment is not in place, the distance between the gluing machine press roller and the sizing roller is not enough, the uneven distance between the heavy press roller and the heating plate, the press roller and the heating plate is too low, the automatic unloading of the gluing machine press roller mechanism is decreased, and the corrugating roller is seriously worn out High enough. Cardboard warpage warpage of cardboard are common with upper and lower bends, longitudinal and longitudinal warpages, and diagonal warp. The main cause of board warpage is that each layer of paper contains different proportions of moisture, forming a layer of paperboard bonding and forming. Different cardboard shrinkage, when the cooling set will cause the cardboard to bend, the speed is slow, less sizing, bonding machine heating plate surface temperature is high, the surface paper water content is small, the surface paper preheating angle is too large, it will form a cardboard to Bending direction of the bottom paper is also called bending, on the contrary, the speed is fast, the amount of sizing is large, the surface temperature of the heating plate of the bonding machine is low, the water content of the surface paper is large, the angle of preheating of the surface paper is less, the level of the upper layer of the cardboard is too flat, and the preheating is performed. Large wrap angle, that is caused by the paperboard paper direction bending double under the bending, change the direction of the paperboard to the bottom paper bending method, speed up the speed, increase the amount of lower sizing, reduce the number of bonding machine heating plate, to shorten the cardboard heating time , Reduce the preheating angle of the paper, increase the preheating wrap angle of the upper single paper, and bend the paperboard in the direction of the paper, slow down the speed, reduce the amount of sizing in the lower layer, and increase the amount of sizing in the upper layer. , increase department Temperature, increase the wrap angle preheating tissues, reducing the upper preheat wrap angle. Cardboard pressure line burst caused by cardboard pressure line, high temperature, low water base paper, repeated many times back to the paper, the original paper fiber is short, the original paper physical properties are poor, paper thickness is not uniform, pit paper is not sizing, processing methods, as far as possible appropriate Increase the speed of the vehicle, reduce the angle of preheating the base paper, appropriately lower the system temperature, and increase the amount of sizing.

Corrugated cardboard boxes - No.7, 2005