Grasping together and improving the compressive strength of corrugated cartons (I)

With the rapid development of the market-oriented economy in China, the demand for foreign trade exports has been increasing and the export of goods has become more frequent. In order to achieve the purpose of protecting the goods, the customer's requirements for the outer packaging of the goods as a package are also increasing. Then, how to improve the compressive strength of corrugated boxes has become an important issue before us.

We know that the compressive strength of corrugated boxes is determined by the following two aspects:

Basic factors : It is the main factor that determines the compressive strength of corrugated boxes. It is also an unavoidable factor. Including base paper strength, corrugated type, type of corrugated board, moisture content and other effects of the external environment in circulation.

Variable factors : Factors that can be avoided in the design or manufacture of corrugated boxes. Including the box size ratio, printing area and printing design, opening area and opening position, carton manufacturing technology problems, box machine defects, quality management issues.

Then, when we calculate the compressive strength according to the customer's requirements and use some empirical formulas to calculate the proper paper for the carton (ie, determine the basic factors for the compressive strength of the carton), how can we make the physical properties of the paper What's the biggest change in the carton production process? This is what we are talking about today.

We already know that the factors that affect the compressive strength of carton are not only the basic factors such as the strength of the base paper and the enamel type, but also the influence of variable factors such as the box size ratio, printing area, and design and manufacturing technologies. Then, adjusting and improving the variable factors that affect the compressive strength of cartons has also become a means to improve the compressive strength of corrugated cartons. Completing a good quality carton is actually a process of teamwork.

From the carton design to the production process, all departments should pay attention to the influencing factors of their work on the compressive strength of the carton and reasonably avoid or reduce the influence of these factors in their respective work processes, so as to make the physical properties of the raw materials into the carton physical properties. The conversion is optimized to produce a corrugated box with excellent compressive strength.

First of all, starting from the quality control of the raw paper used as raw materials for cartons, the quality inspection department should do a good job in the inspection of incoming raw materials to ensure that the incoming raw materials meet the required physical indicators, and record the various indicators for future inspection. When the customer has a pressure requirement on the carton, the business department or technical department should use this as a basis to calculate the used paper and ensure that the used raw materials have a reasonable mix. Because the operating level and equipment status of each company are different, and the theoretical compressive strength calculated by the service based on the compressive experience formula is usually higher than 0% of the customer's required compressive strength, the produced cartons can satisfy the customers. The request. Some manufacturers will be even higher. This data can be obtained through the accumulation of data.

Secondly, during the design stage of the carton, the business and design department must fully consider the structural factors that affect the compressive strength of the carton: mainly including the perimeter of the box, the aspect ratio of the box, the aspect ratio of the box, and the printing of the box surface. The area and location of the opening in the tank wall. The average customer will specify the size of the carton, and some customers will require the carton manufacturer to design. When the customer's product is bulk cargo, the business must fully consider the length of the carton and the aspect ratio. The perimeter is kept constant, the closer the aspect ratio is to 1.4, the higher the compressive resistance of the carton. If only considering the compressive strength of the corrugated box, the ideal ratio is 1.2-1.4. Of course, the actual design process must also consider factors such as placement of the container transport process. In addition, the design department should also consider the position and shape of the printing layout and die-cut hole when designing the carton. Since the bearing capacity of corrugated cardboard is mainly determined by the shape and structure of the corrugated medium, the corrugated shape of the cardboard should be avoided as much as possible during the design process. Such as excessive printing area, full-page printing, horizontal strip printing, multiple overprint, etc. will seriously damage the shape of the corrugated medium, thereby reducing the compressive strength of corrugated boxes. After printing on corrugated boxes, the compressive strength will be lost by about 5%, and some will reach 45%. Usually, some interior goods will require handling or ventilation. It is often necessary to die-cut clasps, vents, etc. on the side walls. However, regardless of the kind of hole to be played, it is necessary to follow the following principles: The number of damaged corrugated sheets should be as small as possible, and the position of the opening should be as far as possible from the edge of the corrugated box. If the size of a carton is 405 x 270 x 270mm, when the φ30mm hole and the φ15mm x 75mm hole are punched at the same position on the carton, the carton's compression resistance is 89% and 92, 2 of the non-punched carton, respectively. %. Although the long hole area of ​​the medium φ 15mm x 75mm is larger than that of the φ30mm hole, the impact of the carton on the compressive strength of the carton is relatively small due to the small number of watts damaged. In addition, the different arrangement of the vent holes has different effects on the compressive strength of the carton. For example, the right figure shows the order of the compressive strength of the different arrangements of the 20 mm and 20 mm x 10 mm long holes. Therefore, in the design stage, the impact of various factors on the compressive strength of the carton must be fully considered, and a scheme with a small impact on the compressive strength should be adopted as much as possible.

(to be continued)