The Flexibility Tester is designed according to China's national standard GB/T2679.5-1995 (Determination of Flexibility of Paper and Paperboard) and features an opto-mechanical integration structure. It automatically counts the number of double folds of the tested sample. The instrument utilizes photoelectric control technology, allowing the folding clamp to automatically return to its original position after each test, facilitating the next operation.
The instrument boasts powerful data processing capabilities: it not only converts the double fold count and corresponding logarithmic values of a single sample, but also statistically analyzes the experimental data of multiple samples within the same group. It can calculate the maximum, minimum, average, and coefficient of variation for the samples in the group, storing these data in a microcomputer and displaying them through a digital tube. Additionally, the instrument is equipped with a printing function.
1. Tension Spring Calibration: Place weights on the plate and observe if the pointer reading matches the weight. Verify at three points: 4.9, 9.8, and 14.7N, with three trials at each point. If there is deviation, adjust the pointer position to reach the correct value. For minor deviations, use the fine-tuning screw for adjustment.
2. Tension Indication Verification: Press the tension rod to align the pointer at the 9.8N mark. Clamp a high-strength sample between the upper and lower clamps. After folding the machine 100 times, stop the machine, then slowly turn the knob by hand to fold the folding head back and forth once. Meanwhile, observe that the change in the pointer's indication should not exceed 0.34N.
3. Tension Rod Friction Test: Place the weights on the weight plate, gently lift the tension rod with your hand first, then slowly lower it to the balanced position and read the value on the scale as F1. Next, pull the tension rod down and then slowly release it to return to the balanced position, reading the value as F2. The friction force of the tension rod must not exceed 0.25N, with the calculation formula being: F = (F1 - F2) / 2 < 0.25N
