Corrugated box anti-stress test

The inspection of export packaging is carried out in accordance with the "Procedures for Inspection of Exported Packaging Corrugated Paper Containers" (SN/T 0262-93) (hereinafter referred to as the "Regulations"). According to regulations, there is an important technical indicator - empty box anti-pressure, it is to measure whether the carton can protect the internal goods in the transport process from external damage, safe and smooth export one of the important basis for judgment. Of course, it is very easy to judge simply whether it is qualified or not. However, in the spirit of “checking service,” how should we do a good job of “serving the enterprise”? With this problem, we go deep into the enterprise to understand the situation and carry out extensive practice verification. , And consulted a large number of technical reference materials, initially opened its mysterious veil. The following will talk about some superficial views for your reference, hoping to benefit the inspection of export packaging.

In the daily inspection work, we have encountered this situation several times: In order to meet the customer's suggestion of the pressure resistance of the empty carton box, the carton manufacturing enterprise has been tirelessly adjusting the matching of the carton's materials, but this is often counterproductive and has not only failed to achieve The requirements of the regulations increase the cost of the carton. What is the reason for this? Generally speaking, the better the materials used, the higher the pressure resistance of the empty containers. However, after a large number of experiments, we have found that there are many factors that affect the resistance of carton empty containers, not just this one.

First of all, empty tank resistance is the most important test item in the physical performance testing of cartons, and it also best reflects the overall quality level of the cartons. It has the greatest impact on the following aspects: material mix, box design, boxing process.

A carton is composed of multiple layers of paper through a certain manufacturing process. The physical properties of paper have a direct impact on the size of the empty box against pressure, especially the paper's ring pressure strength. At the same time, different paper combinations will get different empty boxes against pressure. Not only must the cost be low, but also it must be of good quality. This must have rich practical experience.

The box design includes a lot of content, let us study the size of the carton. The length, width and height of the carton are important factors affecting the resistance of the empty container to pressure. The formula for calculating the pressure resistance of an empty box is: (The value calculated by this formula refers to the empty box resistance that a carton theoretically should reach)

P=G×K×(H/h-1)×9.8, where:
P-empty box pressure resistance, N;
G - gross weight of a single carton, kg;
K-safety factor;
H- stacking height 3m;
H-box height, m.

From the above formula, we can get such a conclusion: When G, K and H are all the same, the higher the carton, the smaller the P; the lower the carton, the greater the P. In theory, what is the actual situation?

We use the same technology, the same material carton, divided into the following two conditions for testing:

1. The length of the carton is the same and the width is the same. The height of the box is divided into six levels: 10cm, 20cm, 30cm, 40cm, 50cm and 60cm. (figure 1)



The repetitive inspection results of the three groups of cartons are as follows (Figure 1): When the box height is increased from 10cm to 30 or 40cm, the value of the pressure resistance of the empty box decreases greatly; when the box height increases from 30 or 40cm to about 50cm, The value of the pressure resistance of the empty box decreases accordingly; when it exceeds 60 cm, the change tends to be gentle.

2. When the height and width of the carton are constant, the length is divided into five grades: 30cm, 45cm, 60cm, 75cm, and 90cm. (figure 2)



The repetitive inspection results of the three groups of cartons are as follows (see Figure 2): The longer the box length of the carton, the greater the pressure resistance of the empty box; when the box length reaches 75cm, the pressure resistance of the empty box tends to be gentle.

It can be seen that the size of the carton has a direct impact on the resistance of the empty container. Foreign professionals have studied that the ratio of the length and width of the carton is 1.4:1. (to be continued)