Do you know the factors affecting the compressive strength of corrugated boxes?

Corrugated boxes have good stiffness, strength and cushioning properties. With the advantages of environmental protection, low cost, and easy storage and transportation, they have gradually replaced packaging containers such as wooden boxes and become the main force of transportation packaging. In order to ensure that the contents are not damaged during storage and transportation, all strength indicators of corrugated boxes must meet the requirements for use. As one of the important indicators of corrugated boxes, compressive strength can reflect the comprehensive characteristics of the entire box-making process and the inherent strength and quality of corrugated boxes. Therefore, the study of compressive strength is of great significance to improve the performance of corrugated boxes, reduce the rate of logistics cargo damage, and reduce the consumption of raw materials.

The compressive strength of corrugated boxes refers to the compressive strength of corrugated boxes, which refers to the maximum load and deformation of the box when the dynamic pressure is evenly applied by the pressure testing machine. The compression test process is divided into four stages: the first is the preload stage to ensure that the carton is in contact with the compression machine platen; the second is the stage when the transverse pressure line is pressed down, at which time the load increases slightly and the deformation changes greatly; The third is the compression stage of the side wall of the carton, at which time the load increases rapidly and the deformation increases slowly; the fourth is when the carton is completely destroyed, which is the crushing point of the carton. The following are the factors affecting the compressive strength of corrugated boxes:

First, the manufacturing process of corrugated boxes

The manufacturing process of corrugated boxes mainly includes processes such as printing, die-cutting and indentation, and opening. The larger the printing area and printing pressure, the greater the loss of compressive strength of the corrugated box. When the indentation line is parallel to the corrugated direction, the impact of the indentation process on the compressive strength of the corrugated box is small; but when the indentation line is perpendicular to the corrugated direction, the compressive strength of the corrugated box is more affected by the indentation process. big. In addition, research has proved that the closer the opening of the corrugated box is to the center of the carton, the smaller the impact on the compressive strength of the corrugated box; the farther from the center of the carton, the greater the impact on the compressive strength of the corrugated box. It should be noted that opening holes at the upper end of the corrugated box has a greater impact on its compressive strength than opening holes at the lower end.

Second, the structure of corrugated boxes

Different structures of corrugated boxes have different effects on their compressive strength. The impact is mainly concentrated in the aspect ratio, height and perimeter of corrugated boxes. The test data show that the change of aspect ratio has a very obvious effect on the compressive strength of corrugated boxes. Under the condition of constant circumference and height of corrugated boxes, the compressive strength of corrugated boxes is changed when the aspect ratio changes from 1.0 to 2.0. It shows a trend of increasing first and then decreasing. When the aspect ratio is around 1.4, the compressive strength of corrugated boxes reaches the maximum. When the height of the corrugated box is high, the stability of the stacking will become worse, and the compressive strength will also decrease. In addition, the compressive strength of corrugated boxes has a positive correlation with its perimeter, that is, within a certain range, the longer the perimeter of the corrugated box, the higher the compressive strength, and vice versa, the lower the compressive strength.

Thirdly, properties of corrugated base paper and core paper

The raw material of corrugated boxes is one of the important factors that determine the compressive strength of corrugated boxes, mainly in two aspects: on the one hand, the quality of corrugated base paper and core paper and whether the combination is reasonable have a significant impact on the compressive strength of corrugated boxes; On the another hand, the comprehensive ring compressive strength of corrugated base paper has a significant linear relationship with the compressive strength of corrugated boxes.

Fourthly, environmental conditions for storage and transportation of corrugated boxes

1. The influence of humidity: Most of the domestic corrugated base paper is made of straw pulp, the main components are cellulose, hemicellulose and lignin, and the glucose group is the basic chemical unit that constitutes these components, so that cellulose, hemicellulose, lignin, etc. All elements have strong hydrophilicity. Therefore, the environmental humidity has a significant impact on the mechanical properties of corrugated cardboard. The researchers used the finite element method to study the effect of environmental humidity on the compressive strength of corrugated boxes. The results showed that the compressive strength of corrugated boxes decreased with the increase of environmental humidity, and the decline was more obvious.

2. The impact of stacking: In order to reduce logistics costs, many businesses will increase the stacking height to improve the utilization of packaging volume. However, under the action of gravity, the goods above will exert pressure on the goods below, and this pressure will cause certain damage to the compressive strength of the corrugated box, and the degree of damage has a great relationship with the stacking time and stacking method. Studies have shown that the compressive strength of corrugated boxes decreases with stacking time. Different stacking methods have different effects on the compressive strength of corrugated boxes. Common stacking methods include staggered stacking and overlapping stacking. When overlapping stacking, the corners of corrugated boxes bear the highest pressure. The compressive strength required in this case is the highest.

3. Influence of vibration and shock during loading, unloading and transportation: In recent years, mechanical loading and unloading methods have been gradually popularized and applied in logistics and transportation, but this undoubtedly increases the number of times that goods are subjected to external vibration and shock during the circulation process. In actual transportation, the vibration and impact strength of corrugated boxes is related to the means of transportation and transportation distance. In railway transportation, the vibration impact strength is mainly affected by the transportation distance. The longer the transportation distance, the stronger the vibration impact of the corrugated box. In automobile transportation, the vibration impact strength is not only affected by the transportation distance, but also related to factors such as road conditions, driving speed, and the placement of goods in the carriage. The greater the vibration impact strength during transportation, the greater the impact on the compressive strength of the corrugated box. During the loading and unloading process, the four corners and edges of the corrugated box have a great influence on its compressive strength.