The compressive strength of the carton is the most important quality index required by many commodity packaging. During the test, the corrugated carton is placed between two pressure plates and pressed to the pressure when the carton is crushed, which is the compressive strength of the carton, expressed in KN.
1. The compressive strength of the predetermined carton
The carton is required to have a certain compressive strength, because the carton stacked on the lowest layer is subjected to the pressure of the upper carton during the storage and transportation process after packaging the goods. In order not to collapse, it must have a suitable compressive strength. The strength is calculated by the following formula: P=KW(n-1) where P—-compressive strength of the carton, N;W—-the weight of the carton after loading, N;n—-the number of stacking layers ;K—-stacking safety factor, the number of stacking layers n is calculated according to the stacking height H and the height h of a single carton, n=H/h
The stacking safety factor is determined according to the number of layers of cargo stacking. The national standard stipulates that: the storage period is less than 30d, take K=1.6; the storage period is 30d-100d, take K=1.65; the storage period is greater than 100d, take K=2.0.
2. Calculate the compressive strength of the carton according to the raw materials
After the compressive strength of the carton is predetermined, the appropriate carton board and corrugated base paper should be selected to produce corrugated cartons to avoid waste caused by blind production; there are many formulas for calculating the compressive strength of the carton according to the ring compressive strength of the base paper, but they are more concise and practical. The Kellicutt formula is suitable for estimating the compressive strength of type 0201 cartons.
3. How to 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 exactly the same as the estimated result. Therefore, the final method to accurately determine the compressive strength of the corrugated carton is to use the carton to compress the carton after constant temperature and humidity treatment. Testing machine test; for small and medium-sized factories without testing equipment, a wooden board can be placed on top of the carton, and then an equal amount of heavy objects can be stacked on the wooden board to roughly determine whether the compressive strength of the carton meets the requirements.
