application
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The ring stiffness testing machine is widely used for measuring the ring stiffness of thermoplastic pipes and fiberglass pipes with circular cross-sections, meeting the requirements of PE double arm corrugated pipes, wrapped pipes, and various pipe standards. It can complete tests such as pipe ring stiffness, ring flexibility, flatness, and weld seam tension. It has button speed regulation, digital display of test force displacement, peak holding, automatic shutdown for damage, overcurrent and overload automatic protection functions.

Product Features
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The compressive strength of cardboard boxes is the most important quality indicator required for many product packaging. During testing, the corrugated cardboard box is placed between two pressure plates and pressurized until the cardboard box collapses, which is the compressive strength of the cardboard box, expressed in KN.

1. Pre order the compressive strength of the cardboard box

The requirement for cardboard boxes to have a certain compressive strength is that the cardboard boxes stacked on the lowest layer during storage and transportation of packaged goods are subjected to pressure from the upper cardboard boxes. In order to prevent collapse, they must have appropriate compressive strength. The compressive strength of cardboard boxes is calculated using the following formula:

P=KW（n-1）
In the formula, P represents the compressive strength of the cardboard box, N
W - Weight of cardboard box after loading, N
N -- stacking layers
K - Stacking safety factor
The number of stacking layers n is calculated based on the stacking height H and the height h of a single cardboard box, n=H/h
The stacking safety factor is determined based on the number of layers of goods stacked, and the national standard stipulates that:
If the storage period is less than 30 days, take K=1.6
Storage period: 30d-100d, take K=1.65
If the storage period is greater than 100 days, take K=2.0

2. Calculate the compressive strength of the cardboard box based on the raw materials

After reserving the compressive strength of the cardboard box, suitable cardboard boards and corrugated paper should be selected to produce corrugated cardboard boxes, avoiding waste caused by blind production;
There are many formulas for calculating the compressive strength of cardboard boxes based on the ring compression strength of the base paper, but the Kellicutt formula is more concise and practical, which is suitable for estimating the compressive strength of 0201 cardboard boxes.

3. Method for determining the compressive strength of cardboard boxes

Due to the influence of various factors in the production process, the compressive strength of cardboard boxes produced from raw materials may not be completely consistent with the estimated results. Therefore, the final accurate method to determine the compressive strength of corrugated cardboard boxes is to test them with a cardboard box compression testing machine after constant temperature and humidity treatment; For small and medium-sized factories without testing equipment, a wooden board can be placed on top of the cardboard box, and an equal amount of weight can be stacked on the board to roughly determine whether the compressive strength of the cardboard box meets the requirements.

Product images
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