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Inspection standard for carton quality
Dec 17, 2018

I. appearance quality

 

1. Printing quality: clear pattern and handwriting printing, consistent chroma, bright and bright; The printing position error of the large box shall not exceed 7mm and the small box shall not exceed 4mm;

 

2. Sealing quality: there are no holes around the box body, and there is no deviation or off-seam after the lid of each box is closed;

 

3. Dimensional tolerance: the inner diameter of the box and the design dimensional tolerance shall be kept in large box plus or minus 5mm, small box plus or minus 3mm, and the external dimensions shall be basically the same;

 

4, cover folding times: corrugated carton roll cover by opening, closing 180 degrees reciprocating folding more than 5 times, one, two kinds of box surface and inner layer, three kinds of box inner layer crack length is not greater than 70mm;

 

In addition, requirements for joint specifications, neat edges, no folding Angle, box surface is not allowed to have obvious damage or stains.

 

Ii. Carton compression strength and influencing factors

 

Carton compressive strength is the most important quality index required by many commodity packaging. During the test, corrugated carton is placed between two pressure plates, and the pressure when the carton is crushed is the carton compressive strength, which is expressed by KN.

 

1. Predetermine the compressive strength of cartons

 

Carton requires a certain compressive strength, because after packaging goods in the storage and transportation process stacked in the lowest layer of the carton under the pressure of the upper carton, in order not to collapse, must have appropriate compressive strength, carton compressive strength is calculated with the following formula: P=KW (n-1) P-- carton compressive strength, n; W-- weight of cartons after loading, N; N -- number of stacking layers; K-- stacking safety coefficient, stacking layer n is calculated according to stacking height H and single carton height H, n=H/ H

 

Stacking safety coefficient is determined according to the number of layers of goods stacking. According to the national standard, K=1.6 is set for storage period less than 30d; K=1.65 for the storage period from 30d to 100d; If the storage period is more than 100d, K=2.0.

 

2. Calculate the compressive strength of cartons according to raw materials

 

After the predetermined carton compressive strength, should choose the appropriate carton board, corrugated base paper to produce corrugated cartons, to avoid blind production caused by waste; There are many formulas for calculating the compressive strength of cartons based on the circular compressive strength of base paper, but kellicutt formula is more concise and practical, which is suitable for estimating the compressive strength of type 0201 cartons.

 

3. Determine the compressive strength of cartons

 

Due to the influence of various factors in the production process, the compressive strength of the carton produced with raw materials may not be completely consistent with the estimated results, so the final accurate determination of the compressive strength of corrugated carton method is the carton constant temperature and humidity treatment with the carton compressive testing machine test; For small and medium-sized factories without testing equipment, the carton can be covered with a board, and then piled up on the board of equal weight, to roughly determine whether the carton compressive strength meets the requirements.

 

4. Factors affecting the compressive strength of cartons

 

1) quality of raw materials

 

Base paper is the decisive factor to determine the compression strength of cartons, as can be seen from kellicutt formula. However, the influence of other conditions in the corrugated board production process is not allowed to ignore, such as the amount of adhesive, corrugated high change impregnation, coating, composite processing and so on.

 

2) water

 

Cardboard boxes with high water content of corrugated board manufacturing, or long storage in a humid environment, will reduce its compressive strength. Fiber is a kind of water absorption is very strong, in the rainy season and the humidity in the air is large, the moisture balance between cardboard and atmospheric environment is very important.

 

3) the box

 

Box type refers to the type of box and the size of the same type of box proportion, they have a significant impact on the compressive strength. Some boxes are made of double-layer corrugated board, the compressive strength of the single-layer box of the same specification is significantly improved; Under the same conditions, the higher the box, the worse the stability, the lower the compressive strength.

 

4) printing and opening

 

Printing will reduce the compressive strength of cartons. Packaging requirements of air permeability of goods in the box surface hole, or on the side of the carton punching and cutting handle hole, will reduce the strength of the carton, especially the hole area is large, biased to one side, etc., the impact is more obvious.

 

5) process deviation

 

Improper pressure line in the process of box making, slotting too deep, combined with weak, etc., will also reduce the compression strength of the box.

 

3. Dynamic performance test of cartons

 

For some specific commodity packaging, such as ceramics, glass products, electrical appliances, instruments, and so on, but also to test the carton cushioning performance of goods, namely simulated transport, loading and unloading, vibration, drop test;

 

1. Drop test

 

Drop the cartons from the specified height according to different postures after the goods are packed, and check the number of times when the goods are packed inside the cartons are perfect or the number of times when the cartons are damaged.

 

2. Inclined plane impact test

 

Turn the carton on the pulley, then slide it down an inclined plane at a certain height, and finally hit the baffle. It is similar to emergency braking during transportation.

 

3. Vibration test

 

The carton packaging goods on the vibration table, so that it is horizontal, vertical direction of vibration, or at the same time by two-way vibration, after a certain time to check the situation of goods or goods carton damage when the time.

 

4. Hexagon drum rotation test

 

Put the carton into the hexagonal rotary drum with impact plate, turn according to the specified number of revolutions, times, and then inspect the goods, carton damage. The above dynamic experiments are destructive, improving the carton and commodity damage resistance is the use of cushion liner, partition or other protective measures when packaging goods. In addition, some packaging cartons also need to do spray, weather resistance and other experiments, according to the two sides of the contract agreement.