Definition
The edge pressure ring compressive strength tester is a special testing equipment used to evaluate the compressive properties of cardboard, corrugated cardboard and similar materials. The instrument simulates the mechanical behavior of materials under pressure in the vertical direction and measures the two key indicators of edge compressive strength and ring compressive strength, providing data support for the quality control and structural design of packaging materials.
How it works:
Based on the principle of compression testing in material mechanics, the equipment applies a vertical compressive load to the specimen through a precision mechanical structure. During the edge compression strength test, the specimen is placed upright between the pressure plates in a specific direction. For ring compression strength testing, the specimen needs to be rolled into a ring shape and placed in a special fixture. The system collects pressure data in real time through the force sensor, records the deformation in combination with the displacement measurement unit, and finally obtains the strength value according to the standard calculation formula.
The core calculation formula is:
R = F / W
R represents the ring pressure strength (kN/m), F is the maximum pressure value (kN), and W is the specimen width (m). The calculation principle of edge compressive strength is similar, but there are differences between sample preparation and stress direction.
Measurement method
The testing process strictly follows international standards (e.g., ISO 3037, TAPPI T811) or national standardized processes. First, prepare the specimen to the standard size and use a special cutter to ensure the edges are flat. Place the specimen on the instrument table and adjust the platen spacing to the standard initial position. After starting the test program, the upper platen is pressed down at a constant rate until the specimen fails, and the system automatically records the pressure peak. Each group of samples needs to be repeated many times, and the arithmetic average is taken as the final result after eliminating the outliers.
Influencing factors
The moisture content of the material can significantly affect the test results, and temperature and humidity balance is required under standard environmental conditions. The quality of sample preparation, such as edge parallelism and incision finish, directly affects the accuracy of the data. In terms of instruments, the parallelism of the platen, the stability of the loading rate, and the calibration status of the sensor are all key factors. Operators should standardize the loading technique to avoid eccentric loads.
Applications:
This equipment is widely used in the packaging manufacturing industry for quality control inspection of packaging substrates such as corrugated cardboard and containerboard. In the paper industry, it is used to evaluate the ring compressive strength of base paper and guide production process adjustments. The quality inspection agency conducts packaging material certification tests according to relevant standards. The R&D department optimizes the material ratio and structural design through data comparison to improve the compressive performance of packaging.
Equipment selection
When selecting, it is necessary to confirm that the maximum test force range covers the expected strength of the measured material, and usually leave an appropriate margin for the selected range. The measurement accuracy should meet the standard requirements, and the force value resolution is recommended to be not less than 0.5% of the full scale. Investigate whether the size of the platen and the fixture configuration are suitable for the specifications of commonly used specimens. The control system should have standard test program preset functions, and the data output format should be compatible with the laboratory management system. The equipment should provide calibration interfaces that meet metrology specifications and consider the ease of routine maintenance.