Factors affecting carton compression resistance
1. paper roll
As we know, base paper is directional, corrugated vertical direction of the carton compressive strength is the best. As cartons are stacked one by one, the most important influence on strength is transverse ring pressure. For paper mills, the longitudinal ring pressure is easy to control, the horizontal ring pressure is not easy to control, but we have to measure the horizontal ring pressure, so many carton factories to make the carton is unstable is this reason.
2. different flute
When the corrugated flute is different, the height and distance of the corrugated are different, and the physical properties of the corrugated are different.
3. Combination of base paper
Corrugated board is composed of kraft paper and core paper, so the physical properties of corrugated board from the combination of base paper.
Flat compression strength: the ring pressure value of core paper is proportional to the flat compression strength of corrugated board.
Vertical compressive strength: the total ring compressive strength of kraft paper and core paper is proportional to the vertical compressive strength of corrugated board and the compressive strength of carton.
Impact strength: The sum of the breaking strength of each layer of kraft paper is proportional to the breaking strength and impact strength of the combined corrugated board.
4. The influence of different sizes on pressure resistance in carton design, the following three points should be paid attention to:
(1) The larger the circumference of the carton, the greater the compressive strength;
(2) When the height of the carton is fixed with the surrounding length, and the width is 06 times the length, the compressive strength of the carton is the maximum;
(3) When the length and width of the carton are fixed, the height starts from 10cm, and every 10cm is increased by an interval for comparison.
5. The influence of box type on pressure resistance
The compression strength of different cases is also different. First of all, square cartons are more ideal than rectangular ones; Secondly, the compression strength of hexagonal carton is greater than that of quadrilateral carton; Finally, the optimal stacking height box is cylindrical.
6, the impact of printing on pressure
The printing area, printing shape and printing position of carton layout have different influence on the compressive strength of carton. In general, the larger the printing area, the greater the reduction rate of carton compressive strength. Full plate field, block and long strip printing has great influence on compressive strength, and should be avoided as far as possible in design. As far as the printing position of the carton is concerned, the compressive strength of the middle part of the positive side mark is higher than that of the edge part.
The degree of impact of printing on compression strength is related to the printing plate pressure, position and area size. Block and strip printing has a greater impact than text printing. Oil-based printing deteriorates more than Flexo. Therefore, the influence of printing bar on pressure is also quite large, the larger the printing area is, the greater the impact on pressure, the printing area is proportional to the deterioration of pressure strength.
7, the influence of rolling hole on pressure
Some cartons have air holes, hand holes, etc., which will also have a significant impact on the compression of the carton. The larger the area of the handle hole, the lower the compression strength. The closer the position of the handle hole is to the body edge and lower edge of the box, the lower the compression strength. The closer the handle holes are to both sides of the carton, the lower the compressive strength. When the hand hole is located in the central part, the compression strength decreases by about 2~4%. Reduce about 10% on the body edge, lower edge and both sides of the box. The smaller the hole, the better. The more in the middle, the less impact on pressure.
Generally speaking, one hand hole on each side can reduce the compressive strength of the carton by 20%, and one hand hole on each side and front can reduce the compressive strength of the carton by 30%.
8. Production and manufacturing factors
In the production of factors affecting deterioration more, plate production has bonding strength, cardboard thickness, core paper forming conditions have an impact. In the production process, the printing pressure, the pressure of the paper transfer roller, the pressure of the paper feed, the pressure of the line, the condition of the fit, the water, etc., these are the factors of the production process.
9. Packaging, storage and transportation factors (2) The nature of packaging products
a. If the product can bear part of the load, it is helpful for compression strength, such as bottles and cans;
b. If the product cannot bear the load or the carton is not full, all the load shall be supported by the compression strength of the carton itself;
c. If the product will emit moisture, such as frozen food, the compression strength of the carton will be reduced:
d. If the contents are flow/liquid, such as soy sauce, powder bag, etc., the carton will protrude outwards, resulting in reduced compression strength of the carton.
a. Cantilever stack height method: The carton part exceeds the pallet, the compression strength of the carton will be reduced by 30 to 50%.
b. Staggered stack height method: This stacking method is the most common. Most of the load is borne by the weakest part of the carton, which reduces the compression strength by more than 50%.
c. Flush stacking height method: In this stacking mode, the upper and lower carton corners are to the carton corners, and the load transfer between layers is more uniform.
Summary: In the design end, the carton type as far as possible do not have high and low pressure line, length to width ratio of 5:3 is the best; Printing and rolling holes as little as possible, if any, should be concentrated in the middle. In the production end, the corrugated should be pressed as lightly as possible, its thickness should be maintained, the fit should be completely glued, and the grooving should be within the press line ±3mm. The lighter the pressure during printing, the better, and the less the better. In the storage and transportation end, the corrugated transverse placement should be avoided, that is, to avoid parallel compression of the carton; Storage and transportation environment, should not be too wet, the relative temperature is about 60% is preferable, storage and transportation time is limited to 3 months, as far as possible to use the four corners of the carton to withstand pressure, not too loose, not less than the top of the height of 5mm, do not overheat wet packaging.
