Standard for strength test of the hottest carton

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Carton strength test standard

I. appearance quality: the market is prosperous

1. Printing quality: the pattern and handwriting are clearly printed, the color is consistent, bright and bright; The printing position error shall not exceed 7mm for large boxes and 4mm for small boxes

2. Sealing quality: there is no leak around the box, and there is no stagger and seam separation after the box covers are closed

3. Dimensional tolerance: the tolerance between the inner diameter of the box and the design dimension shall be kept within ± 5mm for the large box and ± 3mm for the small box, and the overall dimension is basically the same

4. Fold times of cover: the corrugated box swing cover is folded back and forth for more than 5 times through 180 degrees of opening and closing, and the total length of cracks in the surface and inner layers of class I and class II boxes and the inner layers of class III boxes shall not be greater than 70mm

in addition, the joint shall be standard, the edges shall be neat without overlapping corners, and the box surface shall be free of obvious damage or stains

II. Carton compressive strength and influencing factors

carton compressive strength is the most important quality index required by many commodity packaging requirements. During the test, the corrugated carton is placed between two pressing plates and pressurized to the pressure when the carton collapses, which is the carton compressive strength, expressed in kn

1. Predetermined carton compressive strength

cartons are required to have a certain compressive strength, because the cartons stacked at the lowest layer during the storage and transportation of packaged goods are under the pressure of the upper cartons. In order not to collapse, they must have appropriate compressive strength. The compressive strength of cartons is calculated by the following formula:

in the formula, P --------------------------------------------------------------, N

n ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------> if the traditional concrete based structure is adopted

2 Calculate the compressive strength of the carton according to the raw materials

after the compressive strength of the carton is predetermined, appropriate cartons should be selected to form an atmosphere board and corrugated base paper that can be shared and promoted by the industry to produce corrugated cartons, so as to avoid waste caused by blind production

there are many formulas for calculating the compressive strength of cartons according to the annular compressive strength of base paper, but kellicutt formula is more concise and practical, which is suitable for estimating the compressive strength of 0201 cartons

3. Method for determining the compressive strength of corrugated boxes

due to the influence of various factors in the production process, the compressive strength of the cartons finally produced with raw materials may not be completely consistent with the estimated results, so the final method for accurately determining the compressive strength of corrugated boxes is to test the cartons with the carton compression tester after constant temperature and humidity treatment; For small and medium-sized factories without testing equipment, a board can be covered on the carton, and then an equal amount of heavy objects can be stacked on the board to roughly determine whether the compressive strength of the carton meets the requirements

4. Factors affecting the compressive strength of cartons

1) raw material quality

base paper is the decisive factor determining the compressive strength of cartons, which can be seen from kellicutt formula. However, the influence of other conditions in the production process of corrugated board should not be ignored, such as the amount of adhesive, the change of corrugated height, impregnation, coating, composite processing and so on

2) moisture

cartons made of corrugated cardboard with high moisture content, or stored in a humid environment for a long time, will reduce their compressive strength. Fiber is a kind of water absorbent. In the rainy season and when the humidity in the air is high, the moisture balance between the water in the paperboard and the atmospheric environment is very important

3) box type

box type refers to the type of box and the size ratio of the same type of box, which have a significant impact on the compressive strength. Some cartons are made of double-layer corrugated cardboard, and the compressive strength is significantly higher than that of single-layer cartons of the same specification; Under the same conditions, the higher the box, the worse the stability and the lower the compressive strength

4) printing and opening

printing will reduce the compressive strength of cartons. Opening holes on the case surface or punching handle holes on the side of the case will reduce the strength of the carton, especially if the opening area is large and tends to one side

5) processing deviation

improper line pressing, too deep grooving and poor bonding in the process of cartoning will also reduce the pressure resistance of cartons. 3、 Carton dynamic performance test

for the packaging of some specific commodities, such as ceramics, glass products, electrical appliances, instruments, etc., it is also necessary to test the cushioning performance of cartons to commodities, i.e. simulated transportation, loading and unloading, vibration, drop and other tests

1. Drop test

drop the cartons after packaging the goods from the specified height according to different attitudes. Check the quality of the goods packaged in the cartons after a certain number of times, or the number of times the cartons fall when they are damaged

2. Inclined plane impact test

rotate the carton on the pulley, then slide it from the inclined plane with a certain height to meet the needs of placing environmental experiments or installing curve and other experimental devices, and finally impact it on the baffle. It is similar to emergency braking during transportation

3. Vibration test

place the cartons on the shaking table after packaging the goods, so that they are subject to horizontal and vertical vibration, or two-way vibration at the same time. After a certain period of time, check the condition of the goods or the time elapsed when the commodity cartons are damaged

4. Hexagonal drum rotation test

put the carton into the hexagonal drum with impact plate, rotate it according to the specified number of revolutions and times, and then inspect the damage of goods and cartons

the above dynamic tests are destructive. To improve the anti-destructive ability of cartons and commodities, cushion pads, partitions or other protective measures should be used when packaging commodities. In addition, some packaging cartons also need to be tested for spray and weather resistance, which can be agreed upon by both parties according to the contract

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