Plane pressure strength is an important indicator of the quality of corrugated cardboard. The ideal corrugated cardboard not only requires it to have a good supporting force to withstand external forces when it is subjected to the pressure exerted on the surface, but also must have a certain rebound force. And the corrugated cardboard can make the corrugated shape retain its original state of recovery ability to a certain extent. The special effect of corrugated cardboard, which is both rigid and flexible, is one of the main characteristics of protecting packaging products. It is different from other packaging materials. It can be seen from this that the ideal flat compressive strength of corrugated cardboard is not simply required by its hard strength as the only technical indicator.

To make corrugated cardboard have ideal flat compressive strength, the main deciding factor is the quality of core paper and processing technology. The core paper as the raw material is best, but it is often not necessarily fully satisfied by the cost constraints, and the processing technology can be achieved by correct operation and careful adjustment, when the raw material is not very ideal If you work well in processing technology, you can also overcome some of the lack of raw material quality to a certain extent, and produce a relatively ideal corrugated cardboard to achieve a certain flat pressing effect. The following attempts to analyze the technical problems of cardboard processing, rather than the quality of the core paper itself.

(1) The bonding condition of single-sided corrugated is an important factor affecting the flat compression strength

1. On the roller adjustment of the single-sided machine, the measuring roller and the sizing roller should be parallel to the lower corrugating roller to ensure that the sizing is just the right amount. The gap between the sizing roller and the lower corrugating roller depends on the thickness of the corrugated paper, assuming the corrugated base paper The thickness is 0.23mm, and the gap can generally be set at 0.25mm (adjustable range is generally 0.21mm ~ 0.39mm);

2. The quality of the adhesive should be grasped, including the adhesive stage and the viscosity and gelation of the adhesive used on the single-sided machine; the wear degree and abnormal state of the finger guide plate should be constantly checked whether the adhesive causes Corrugated deformation of undesirable transmission affects the flat compression strength.

(2) Beware of corrugation

The main reason for the corrugated tilt is the unevenness of the parallelism, temperature and pinch pressure of the corrugated roll, so it is often necessary to use intuitive or open-sided corrugated cardboard to check whether the gap between the upper and lower corrugated rolls is parallel and whether the pressure is parallel Appropriate, if it is improper, it should be adjusted and corrected in time. Under normal circumstances, the steam pressure of the corrugated roll of the medium and heavy corrugated cardboard machine can be set between 1.2 ~ 1.25Mpa, and the temperature is preferably 150 ℃ ~ 170 ℃. The temperature is higher than the lower corrugated roller, 165 ℃ ~ 175 ℃, the requirements for super heavy or light should be increased or decreased differently. It must be pointed out that in addition to keeping the pressure roller parallel to the corrugated roller, do not increase the pressure too much because of insufficient temperature. From time to time, the tip of the core paper will be damaged and the thickness and strength of the right paperboard will be reduced. To make up for the lack of heat is useless.

The method of checking the heat of the roller can easily measure the temperature change with a pyrometer or a color measuring pen. The color measuring pen is a kind of strong pencil made of composite material. When it touches the roller, it will melt at a certain temperature, so as to determine the temperature and ratio, and as a basis for adjusting the temperature. It is especially convenient if infrared thermometer can be used, it can detect the surface temperature of the corrugated drum in operation without touching the heating container.

(3) Avoid damage to the single-sided corrugated cardboard during transportation

When the single-sided corrugated cardboard is drawn from the single-sided machine, the humidity of the cardboard is relatively high, and it is easy to be damaged and deformed during the traction and transmission process and affect the flat-strength strength. Therefore, when pulling on the bridge, the pulling force should not be too large. The looped single-sided corrugated paper piled on the bridge should not be squeezed and twisted due to overload, and more attention should be paid to grasp the bridge that leads the paper on the bridge to the glue machine. Guidance pull.

(4) Precautions during sizing

 The factors that may affect the flat compression strength of single-sided corrugated cardboard when passing through the glue machine are: whether the guide roller and the applicator roller of the glue machine are kept equal; whether the load of the guide roller can give the adhesive accordingly and does not affect the thickness and thickness of the cardboard Corrugated; whether the amount of sizing should be increased or decreased in time with the speed of the glue machine, to avoid poor bonding effect of the adhesive.

(5) Influencing factors of idling device

 The idle guide rollers (especially the guide rollers of the glue machine that are in contact with the single-sided corrugated paper) of the corrugated board machine, as well as the steam cabinet and belt lifting rod of the double-sided machine. Damage to the flattening strength of the cardboard, the guide roller must be regularly lubricated and maintained to ensure that it runs freely; the steam cabinet must be kept horizontal and clean, and there must be no obstacles on the surface; the position where the belt lifting rod falls must be stable The place is just right.

(6) The harm of the upper pressure imbalance when the cardboard passes through the double-sided machine

 The accumulation of waste paper scraps, dry scars and other contaminants on the belt and the aging and damage of the belt itself will inevitably cause local unevenness or uneven pressure unevenness of the left and right relaxation, which will lead to harm to the adhesion effect and flat strength of the cardboard.

(7) To prevent the pressure of the feed roller from being damaged

 After the corrugated cardboard is drawn from the double-sided machine, it may be damaged due to extrusion when passing through the steel or rubber feed roller of the cutter and the post-processing printing and slotting machine. For the feeding device and the impression cylinder that cut off the feed roller and printing slot, it must be carefully adjusted to keep the pressure balanced and appropriate, and the gap is matched, otherwise it will cause the flattening strength and thickness of the cardboard to be reduced.