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General inspection methods for footwear - wear test method
Standard for Testing the Wear Resistance of Shoe Soles and Forming Bottoms
1. Subject Content and Scope of Application
This standard specifies the test method for the wear resistance of shoe soles and forming bottoms (sheets). It is applicable to the evaluation of wear resistance for shoe soles and forming bottoms (sheets).
2. Principle
A rotating grinding wheel is pressed vertically onto the sample, subjecting it to an abrasion test under a specific load, speed, and time. The length of the wear scar on the sample is then measured.
3. Sample
3.1 Samples can be shoes, soles, or flat test pieces (thickness ≥ 6 mm).
3.2 Each group of samples should consist of at least four shoes, soles, or sheets.
3.3 Sample Pretreatment: Remove any surface layer that may affect the test results. The sample surface must be flat and placed in the test chamber for more than 4 hours.
4. Test Equipment
4.1 The wear tester shall meet the following conditions:
4.1.1 The grinding wheel is a T12 steel wheel with a diameter of ∅20 ± 0.1 × 4 ± 0.1 mm, having 72 teeth, a tooth angle of 90° ± 5°, a tip width of 0.2 ± 0.05 mm, a tip roughness of Ra = 3.2 μm, a hardness of HRC ≥ 55, and a coaxiality of 0.03 mm.
4.1.2 The grinding wheel speed can be adjusted within the range of 100–300 r/min.
4.1.3 The grinding wheel rotates clockwise, operates stably, and has a radial runout not exceeding 0.05 mm.
4.1.4 The load between the grinding wheel and the sample can be adjusted up to 19.6 N.
4.1.5 The grinding wheel must be inspected annually.
4.1.6 The test time is automatically controlled with an accuracy of 0.1 min.
4.1.7 The balance range is 2000 g with an accuracy of 5 g.
4.2 A vernier caliper with a division of 0.02 mm is used for measurements.
5. Test Conditions
5.1 The load is 4.9 N (special requirements can select within 19.6 N).
5.2 The grinding wheel speed is 191 ± 5 r/min (special requirements can select within the allowable range of the testing machine).
5.3 The test time is 20 minutes continuously (special requirements can be selected).
5.4 The ambient temperature is at room temperature.
6. Test Procedure
6.1 Adjust all parts of the testing machine to normal and let the grinding wheel run for 20 minutes.
6.2 Fasten the sample to the left end of the balance with the sole facing up and ensure the wear area is level.
6.3 Adjust the grinding position so it aligns with the flat surface of the specimen (ensuring sufficient area for abrasion), and the grinding wheel must be positioned at the upper left of the sample holder.
6.4 Balance both ends of the scale (the pointer should point to zero). Add the required weight at the right end of the balance (e.g., if the load is 4.9 N, add 500 g) to achieve the specified contact load between the sample and the grinding wheel.
6.5 Adjust the height of the grinding wheel so the balance pointer points to zero, then tighten the grinding wheel shaft.
6.6 Adjust the start time to the desired value.
6.7 Start the machine, adjust the grinding wheel speed to the specified value, and clear the time display to begin the test.
6.8 After the machine stops automatically according to the set time, measure the length of the wear marks on both sides using a caliper.
6.9 If sulfur contamination is found during the test, stop immediately and wash the contaminated grinding wheel with an organic solvent.
7. Test Results
7.1 The test results are expressed in millimeters of the wear scar length, with one decimal place.
7.2 At least two measurement points per sample are taken, and the arithmetic mean of two data sets is calculated. If the wear scar is trapezoidal, the long side should not exceed 10% of the short side.
7.3 The maximum allowable deviation for each test result is ±10%. If there are multiple deviations, the test must be repeated.
7.4 Each sample's test results are reported separately.
8. Test Report
8.1 Indicate that the test was conducted according to this standard.
8.2 Include the sample number, name, specification, grade, sole material, manufacturer or inspection unit, and wear location.
8.3 Describe the sample pretreatment and its conditions.
8.4 Specify the test load, grinding wheel speed, wear time, and laboratory temperature.
8.5 Provide the test results.
8.6 Include the test personnel and date.