[Corrugated cardboard technology] Quality defects caused by pit machine "detoxification"

There are many influencing factors in the production process of a cardboard, including temperature, speed, raw materials, adhesives, equipment adjustment, personnel operation level, responsibility, etc. Quality problems should be adjusted and resolved from the above aspects.

The pit machine is the core part of the cardboard. The pit machine often has some bad products that affect the quality of the cardboard. Based on my own experience, the author lists some problems and solutions for your reference.

Poor fit

In the process of cardboard production, many manufacturers will encounter the problem of poor fit, which should be judged according to the actual situation of cardboard production and then resolved. The moisture of the raw materials is uneven or too humid, causing poor fit.

The author once encountered such a phenomenon. When using paper with a gram weight of 300 grams and a core paper of 180 grams during production, no poor adhesion was found at the single-sided machine, but after slitting the slitter There is a phenomenon that the inner paper and the corrugated paper are separated. After analysis, it is considered that it is caused by uneven moisture of the inner paper and the paper is too moist. The base paper is measured with a moisture meter, and the data is 9.8%, 10%, 13.1%, 15.3% from one side to the other. , 11.9%. It is well known that the moisture content of paper should be 8% ± 2. Because the paper is too moist and causes poor bonding, you should replace the base paper in time and notify the base paper manufacturer to solve it, or reduce the production speed to dry the moisture to ensure that it fits well.

Corrugated rollers or pressure rollers are worn, causing poor fit. When producing paperboard, there is no full-scale production that causes the middle of the corrugated bar or pressure roller to wear and appear concave; when producing narrow widths, there will be poor bonding on both sides or blistering in the middle, and poor bonding on both sides, generally in The cardboard production line with a width of more than two meters is particularly obvious. In this case, emery can be used to grind both sides of the corrugated roller to reduce the concave or replace the corrugated roller and pressure roller.

Insufficient temperature causes poor corrugated board bonding. If the temperature is not enough, the inner paper and the core paper will not be firmly bonded and there will be delamination. It can be seen that the glue is not completely pasted. At this time, the reason for the insufficient temperature should be checked because the steam pressure of the boiler room is not enough. The general production speed is more than 100 meters / minute, and it should be more than 9 kilograms.) The failure of the siphon of the steam trap causes the condensate to be excluded or the pipeline is blocked.

Cardboard collapsed

Insufficient wind pressure causes collapse:

Whether it is a positive pressure cassette type or a vacuum suction type pit machine, the wind pressure is for the corrugated iron corrugated iron to be closely attached to the corrugated rod, so that the glue stick uniformly applies glue to the top of the corrugated, and then Generate two layers of corrugated cardboard. Insufficient pressure supply will cause the corrugation not to cling to the corrugated rod, and this phenomenon can be seen from the side of the glue wheel. It is necessary to check the cause of insufficient wind pressure, check for leaks, or blockage of the wind pipe or insufficient design pressure of the wind, which should be analyzed and solved one by one.

Insufficient temperature causes collapse:

If the temperature is not enough, the core paper entering the corrugated sheet will not be formed by ironing, but will collapse and no corrugated. If the eccentricity of both ends of the corrugation is not adjusted well, the eccentricity of both ends of the corrugation is not adjusted uniformly, and the two ends of the corrugation are not parallel, causing the two sides of the core paper entering the corrugating roll to be uneven and collapse. Both ends are parallel.

Corrugated roller pressure is not enough to cause collapse:

This situation is generally obvious after the corrugation is worn. Check whether the steam pressure or oil pressure is sufficient. Check whether there are parts that cause oil pressure or steam pressure insufficient. If necessary, replace it, and check for steam leakage and oil leakage. Local and resolved in time. The quality of corrugated core paper is not good enough to cause loose edges of corrugated corrugated core paper. The original paper shaft is oval or the paper is too wet. Collapse may occur. Check whether the core paper has the above conditions and replace it if necessary.

Corrugated roller wear caused collapse:

Many cardboard boxes produce corrugated rollers with uneven wear due to the production of various specifications of cardboard, or fail to produce full-width cardboard, causing the corrugated roller to appear concave. When it is narrow, it is more likely to collapse. In this case, the corrugated rod should be replaced according to the corrugated use, or the pressure of the corrugated roller should be increased.

Unreasonable design of corrugated stick suction slot:

There are two kinds of suction slots. One is to install paper guides so that the two layers of corrugated cardboard that have been fitted are led out and smoothly enter the paper feeding belt on the flyover; the other is the air outlet generated by the vacuum suction pump. After forming the corrugated core paper, the corrugated core paper is tightly attached to the corrugated roller. If the distance of the suction groove is too wide, the effect of adsorption will not be achieved and the corrugation will occur.

Corrugated cardboard wrinkled

The raw material is not good, and the tension on both sides of the inner paper is different. You can feel it by hand when this happens. You will find that the inner paper is loose and smooth after passing through the preheating cylinder. The first solution is to replace the raw materials: the second is Install the tension parallelizer; the third is to make a device that can be manually adjusted to find the loose edge, use manual adjustment to make it tension.

The speed of the machine is too slow to cause wrinkling. Generally, this situation is more common when producing wide-width and high-weight cardboard on a single A machine; this situation occurs when the speed is less than 30 meters per minute. In the case of the above, the vehicle speed should be increased appropriately to reduce wrinkling.

When the gap between the pressure roller and the corrugated roller is unevenly adjusted or if wrinkling occurs due to improper adjustment, the gap between the pressure roller and the corrugated roller should be adjusted in time according to the situation.

The above are the causes and solutions of some common cardboard defects on the pit machine. The author believes that when a bad cardboard occurs, it should be analyzed according to the defective cardboard. For example, what kind of phenomenon is the above-mentioned collapse phenomenon caused? The phenomena that come out are not the same. It is necessary to analyze and eliminate one by one according to the situation seen on the spot. Do not blindly determine the cause of the problem. This will only increase the complexity of the problem, and it will be impossible to start.

There are many factors that affect the ability to produce qualified quality, including equipment adjustment, temperature and speed, adhesives, and personnel operations. In fact, these factors can be complementary. If the quality of the raw materials is slightly bad, but if the adjustment and wear of the equipment are within the normal use range, it can make up for some of the deficiencies of the base paper.