Definition
A flexibility meter is a laboratory testing device used to evaluate a material's resistance to breakage under repeated folding conditions. The instrument quantifies the fatigue resistance of materials by simulating the reciprocating folding process at specific angles and tensions, and measuring the number of folds until they break. This indicator has reference significance in product quality control and research and development in many industries.
How it works:
The core working principle of the instrument is mechanical reciprocating motion. The specimen is clamped between two opposing fixtures and remains straight under set tension. A fixture performs reciprocating motion under the action of the driving mechanism, so that the specimen is repeatedly bent at a certain angle around the axis. Each complete reciprocating motion is counted as one fold. The instrument continues to run until the specimen breaks, at which point the total number of folds is automatically recorded. Some models can be adjusted in terms of folding angle, movement frequency and applied tension to suit different standard requirements.
Measurement method
Measurements usually follow a standardized process. First, a bar specimen of the specified size is prepared according to the relevant standards. The specimen is properly mounted in the upper and lower clamps, ensuring that it is straight and subjected to preset initial tension. Set instrument parameters such as folding angle (usually 135° or other specified angle) and swing speed. When the instrument is started, it automatically performs reciprocating folding. When the specimen is completely broken, the instrument automatically stops and records the final number of folds. Multiple measurements are usually taken from the same batch of samples, and the average of the results is taken as the reported value.
Influencing factors
Measurement results are influenced by a variety of factors. The material's own properties are fundamental, including its fiber structure, flexibility, and internal bonding strength. The larger the folding angle or the higher the tension applied, the greater the stress on the material, which may lead to a decrease in the number of folds. Environmental conditions such as temperature and humidity can affect the physical properties of materials, and standard tests usually require constant temperature and humidity conditions. In addition, the standardization of specimen preparation, such as smooth and burr-free edges and aligned gripping, can also affect the repeatability of test results.
Applications:
The instrument has a wide range of applications. In the paper and packaging industry, it is used to test the service life and durability of paper, cardboard, corrugated boxes, etc. In the textile and apparel sector, it is suitable for evaluating the fatigue resistance of fabrics, leather, nonwovens and other materials. They are also commonly used for performance verification in reliability testing of flexible packaging materials, plastic films, metal foils, and flexible circuit substrates in the electronics industry.
Equipment selection considerations
There are many aspects to consider when choosing equipment. First of all, the standard system to be followed by the test should be clarified to ensure that the design of the instrument meets the specific requirements of the standard for fixtures, motion trajectories, angle control and counting accuracy. Secondly, according to the thickness and strength range of the material to be measured, confirm the tension range that the instrument can provide and the fixture compatibility. The test efficiency of the device, such as the maximum folding frequency, can affect the cycle of high-volume testing. Data output and management functions, such as support for data storage, transfer, or connection software, are also common requirements in modern laboratories. Finally, the durability, ease of maintenance, and technical support capabilities of the supplier are important factors to ensure long-term stable operation.