Definition of side/ring pressure tester
Side pressure testing machine and ring pressure testing machine are special testing equipment used to evaluate the compressive properties of cardboard, corrugated cardboard and similar materials. The edge pressure test mainly measures the ability of the edge of the cardboard to withstand pressure in the vertical direction, while the ring pressure test is used to measure the compressive strength of a certain width of paper strips after being rolled into a ring. These two tests play a fundamental role in the quality control and research and development of packaging materials, paper products and other industries, and their test results are often used as important indicators of material mechanical properties.
Test Principle:
The core principle of edge pressure and ring pressure test is compression test. The equipment uses a precision mechanical or servo drive system to make the upper platen move downward at a constant speed, exerting a gradually increasing compressive force on the vertically placed specimen. The force sensor monitors and records the load change during compression in real time, and the displacement sensor synchronously records the deformation of the specimen. The test is terminated when the specimen collapses or reaches a preset deformation. The system calculates the edge or ring pressure strength based on the recorded peak force value and the original size of the specimen according to the standard formula. Its basic strength calculation formula is:
R = F / L
Among them, R represents the edge pressure strength or ring pressure index (usually in kN/m or N·m/g), F is the maximum force (N) when the specimen is crushed, and L is the initial length (side pressure) or quantitatively converted parameters of the specimen.
Measurement method
The measurement process must strictly follow relevant international or national standards, such as ISO 3037, TAPPI T811, GB/T 2679.6, etc. For edge pressure testing, a rectangular specimen of a specific size is cut out of the sample and the edges are flat and vertical. The specimen should be placed upright in the center of the lower pressure plate of the testing machine, so that the force direction is perpendicular to the corrugated direction. For ring pressure test, a paper strip of the specified size should be inserted into a special coiler to form a ring, and the ring specimen should be placed between the upper and lower platens of the testing machine. Before testing, the appropriate platen speed (e.g. 12.5 mm/min ± 2.5 mm/min) and pre-pressure should be set. Once the device is started, the system automatically completes compression, data acquisition, calculation, and report generation. To ensure the accuracy of the results, it is often required to test a set of specimens multiple times and take an average.
Influencing factors
The accuracy of test results is influenced by multiple factors. In terms of specimens, the moisture content, fiber orientation, uniformity of the material, as well as the cutting accuracy and edge state of the specimen are key factors. In terms of environment, the temperature and humidity need to be controlled within the standard limit, because the mechanical properties of paper materials are sensitive to humidity. In terms of equipment, the parallelism of the platen, the stability of the loading speed, the calibration status of the force sensor, and the suitability of the test fixture all affect the measurement data. In terms of operation, the centering of specimens, the application of pre-pressure, and the standardization of the testing process also need to be strictly controlled. Understanding and managing these factors is a prerequisite for reliable, comparable data.
Applications
The application of edge pressure and ring pressure testing machines is mainly concentrated in the packaging and paper industry. They are used to determine the edge compressive strength of corrugated cardboard, which is the basic data for predicting the compressive performance of cartons and designing packaging structures. Ring compressive strength is often used to evaluate the stiffness and bearing potential of materials such as containerboard and corrugated base paper. In addition, in the product quality control process, these tests are used to monitor the performance consistency of raw materials and finished products. In the field of research and development, we provide data support for material improvement and new product development by testing the compressive properties of different formulations, processes or structural materials. Relevant test data is also an important basis for quality acceptance between buyers and sellers in the supply chain.
Equipment selection considerations
When selecting a side/ring pressure tester, a systematic evaluation is required. First, you need to clarify your testing needs, including the standards to be followed, the type of material being tested, the expected range of force values, and the required test accuracy. The core parameters of the equipment include range, resolution, accuracy level, and test speed range, ensuring that it meets standard requirements with appropriate margins. Rigidity, long-term stability, and data repeatability of equipment are quality metrics to focus on. The control system should be intuitive to operate, and the software functions should support standard test processes, data calculations, statistical analysis, and report export. In addition, the supplier's technical support capabilities, the ease of calibration services, the availability of common spare parts, and the ergonomics of the equipment are also important practical considerations. Evaluating these aspects comprehensively helps in selecting equipment that aligns with specific laboratory needs.