Seam Slippage Test | Slippage Resistance of Yarns at a Seam in Woven Fabrics

Determine the resistance offered by thread systems of woven fabrics to slippage at a sewn seam by Fixed load method (ISO 13936-2).

Apparatus and material specification:

• Tensile testing machine with a constant rate of extension of 50 mm/min, with an accuracy of +/- 10%.
• The machine shall be capable of setting the gauge length to 100 mm
• Clamps must have an smooth, flat surface: 1 clamp: 25x25 mm / 2.clamp: 50x25 mm
• Sewing machine: electrically operated, single needle, lock stitch
• Sewing thread: white 100% polyester core spun / yarn count: 45 tex (+/- 5)
• Needle size 90
• Stitch rating: 5 stitches per centimetre

Procedure:

1. Size of the rectangular specimens must be in length 200 mm and in width 100 mm.
2. Cut 5 specimens in warp direction which will be used to determine weft slippage and cut 5 specimens in weft direction which will be used to determine warp slippage
3. Fold the specimen with the face inwards in half by putting the two shorter edges together
4. Stitch a seam with 5 stitches per cm parallel to and at a distance of 20 mm from the fold.
5. Cut each specimen 12 mm from the sewn seam line, cutting through both layers of the fabric. The seam allowance shall be the same on each side of the cut.
6. Condition the specimen in a standard temperature atmosphere: relative humidity of 65% ± 2%RH at a temperature of 20°C ± 2°C.

7. Set the clamps of the tensile testing machine a distance of 100 mm (+/- 1 mm) apart, taking care that the clamps are properly aligned and parallel to each other.
8. Secure the specimen symmetrically in the clamps with the seam midway between, and parallel to, the edges of the two clamps.
9. Set the moving clamp in motion and when the maximum force is achieved, immediately reduce the load on the test specimen to 5 N at a constant rate of extension of (50 ± 5) mm/min.
10. Immediately measure the width of the seam opening at the widest place to the nearest mm.
11. Repeat this procedure with the remaining test specimens.

Evaluation:

Calculate to the nearest mm the mean warp slippage and weft slippage values of the measured seam.