Stitch method fabric stiffness testerTest steps:
sample preparation
Size and quantity: Take 5 representative samples with dimensions of (100 ± 2) mm × (100 ± 2) mm parallel to the longitude (straight) and latitude (horizontal) directions, ensuring that each sample is not in the same latitude and longitude position.
Humidity control treatment: Reduce humidity to equilibrium state (usually for more than 24 hours) in the standard atmosphere specified in GB/T 6529 (temperature 20 ± 2 ℃, relative humidity 65 ± 2%).
Positive and negative markings: Clearly distinguish the front and back of the sample to avoid confusion during testing.
Instrument settings
Slot width adjustment: Select the slot width (5.0mm, 10.0mm, 20.0mm) based on the thickness of the sample. If 10.0mm cannot meet the requirements (such as the sample being too thick or too thin), it can be switched to 5.0mm or 20.0mm.
Replacement of distance pins: Use matching distance pins to fix the slot width, ensuring that the allowable deviation does not exceed ± 0.05mm.
Test head calibration: Check whether the plate-shaped test head (length ≥ 120.0mm, thickness 2.00 ± 0.05mm, measuring port arc radius 1.00 ± 0.02mm) is equidistant from both sides of the slot (deviation ≤ 0.05mm).
Depth setting: Set the sample depth to (8.0 ± 0.5) mm and travel speed to (1.20 ± 0.30) mm/s.
Meridional testing
Positive test:
Place the sample face up on the sample table, so that the longitudinal direction is perpendicular to the slot and covers the slot.
Adjust the position of the sample so that 1/3 is in front of the slot and 2/3 is behind.
Reset the instrument reading, start the testing head and press the sample into the slot to the set depth before returning.
Record the maximum force value as the longitudinal positive stiffness value.
Negative test:
Move the sample away and flip it 180 ° along the upper edge so that the opposite side faces upwards.
Repeat the front test steps and record the back stiffness value.
Latitudinal testing
Positive test:
Turn the sample face up and clockwise by 90 ° to make the latitude perpendicular to the slot.
Adjust the position of the sample (1/3 in front, 2/3 behind), reset the reading to zero, and then test.
Record the stiffness value of the latitudinal front.
Negative test:
Move the sample away and flip it 180 ° along the upper edge so that the opposite side faces upwards.
Repeat the latitudinal front test steps and record the back stiffness value.
repeated test
Repeat the above steps for the remaining 4 samples, completing a total of 5 samples in both longitude and latitude directions, and 10 measurements on both sides.
Result Calculation
Unidirectional average value: Calculate the average stiffness values of the front and back sides of 5 samples in the warp and weft directions respectively.
Total stiffness value: Take twice the sum of the average stiffness values in the warp and weft directions as the total stiffness value, in millinewtons (mN), rounded to an integer according to GB/T 8170.