This Seam Fatigue Tester tests the strength of a sewn seam in a fabric. It operates by lifting a 3 kg weight using the sewn fabric as a 'tow rope’. The 3 kg mass is dropped onto a shelf at the end of each stroke and lifted again by the fabric. The shelf height is adjustable so that the mass can be set down gently without too much jerk. The machine is double-ended. Thus, two sets of specimens can be tested at each end.
It can also evaluate the strength of sewn seams in leather, and vinyl. A specimen is installed into a station with a clamp spacing distance as required by the appropriate test specification. A 29.4 N (3 kgf/6.6 lbf) is attached to each outer clamp carriage. At the completion of testing, the sample is evaluated for tearing, hole elongation and thread breakage. Thus, the Seam Fatigue Tester tests the quality of textiles.
The Seam Fatigue Tester has been specially designed and manufactured with relevance to International Standard GMV3405, to test the strength of a sewn seam.
The principle of the test is to evaluate seam fatigue using a run of loading and un-loading cycles applied to a seam sewn in a textile material test specimen. The seam appearance and needle hole elongation is evaluated upon completion of the set cycles.
Specifications
- Adjustable shelf height
- Double ended with 4 specimen testing capability
- Safety Enclosure with limit switches in place
- Cycle Speed: 30 cycles/min variable
- Stroke: 150mm
- Jaws: 4 x sets 120mm wide
- Pre-determined Counter: 6 digits
- Dropping Mass: 4 x 3kg
Test Specimens
For this test, eight (8) test specimens are required, each measuring 100mm x 100mm. When cut, each edge shall be either parallel or perpendicular to the machine direction of the material.
Prior to conducting tests
Test specimens shall be conditioned and prepared prior to testing on the Seam Fatigue Tester with relevance to the standard. Sew a seam in the middle of the fabric after folding in half.
Procedure
Once test specimens have been conditioned and prepared, perform the following steps:
1. Level/stabilize machine by adjusting Feet height with a 13mm spanner (spanner not provided).
2. Open the Top Lid to gain access to the Sample Clamps.
3. Open up each of the clamps by lifting up the red lever.
4. Place sample centrally under the Sample Clamp and push the red lever down one at a time. Ensure the seam is centred between the two Sample Clamps.
5. Operator will have to manually move the centre carriage to each side to ensure weights are supported when clamps are applied.
Note: The distance between the Sample Clamps clamped on the test specimen should be 120 ± 1mm. If the test specimen extends to more than 140mm between the clamps during the test, it should be re-clamped to the 120 ± 1mm set spacing.
6. Repeat step iv for all four Sample Clamps.
7. Check adjustment of Weight Supporting Platform so that when the Carriage is on the left most extremity, that the weight is supported by the Weight Supporting Platform.
8. Repeat process for the right hand side.
9. Close the Top Lid.
10. Ensure Front Doors are also closed.
11. Ensure the Emergency Stop Switch is not depressed. Twist to release the switch.
12. Turn on power to machine. Twist the ON/OFF Switch. Light will illuminate when in the on position and the Counter will also be illuminated.
13. Set the Counter by using any of the six buttons under the LCD screen. Green numbers are the number of tests to be performed. Red numbers are the number of tests that have been performed. Red numbers will only change once a test has started.
14. Press the Reset Button on the counter if necessary. This will reset the number representing the total tests performed.
15. Reset the Totaliser if necessary. This is the number of tests that have been performed after completing several cycles with the Counter.
16. Press the green Start Button to begin testing. Run the machine at 30 cycles/min with the load weight of 3 ± 0.1kg NOTE: If machine does not start, check Emergency Stop Button has not been activated.
17. Evaluate the test specimens for needle hole elongation while it is still on the machine with the 3kg weight applied.
Evaluation and Results
• Measure the maximum length if the holes created on each side of the seam due to needle hole elongation (measurement taken from the centre of the stitch line to the other side of the elongated hole)
• Assess the appearance of the seam after testing, making a note of any seam fractures, yarn slippage, yarn breaks or any other changes which are clearly visible and report this change
• Report the largest needle hole elongation, in mm, for each test specimen
• When opening the Sample Clamps, ensure Weights are supported. Move to centre Carriage manually to each side to ensure weights are supported when Sample Clamps.