Top-10 fabric defects every buyer should know

When sourcing fabric from Asia, it is important to set a quality standard for the acceptance of products, and communicate them well to your supplier prior to confirming production. To help you with that and guide you through common fabric defects, V-Trust have prepared a list of the top-10 common fabric defects that every buyer should know. You can see how and why fabric defects appear, as well as note the classification of the mentioned defects in your checklists.

1. Nep

So called cotton grains, or knots and neps – this defect is very common in the roving of low-grade raw cotton production facilities. It looks like a knot of entangled fibers embedded in the yarn, which, if removed from the finished fabric, can lead to yarn breakage. Sometimes neps are also placed intentionally to give fabric a designed look.

Cause:

1. Formed by dead fibers in the raw cotton, which were not completely removed during the cleaning process.
2. During the combing process of cotton, the cylinder’s needle or needle board was not sharp enough, or the spacing between them was set improperly.

Defect classification: 1 point (according to 4-point system)

2. Slub

The slub refers to a thick yarn / flying waste yarn in the middle with tapered ends. Usually the diameter of its middle part is several times bigger than that of the adjacent normal yarn.

Cause:

1. The defect is formed when the roving is fed into the spinning: once the density of the fiber is not uniform, the smaller dense fusiform fiber bundles lead to slub formation.
2. The roller and leather ring of the worsted machine fails to control the roving feeding uniformly.

Defect classification: 1 point

3. Color fly yarn

Sometimes on the surface of the fabric you can find unrelated color fly yarns, which are mixed into the fabric with the main fabric colors.

Cause:

It happens because different color fibers float in the air of the spinning room, or gather on the surface of the machine feeding station, and get wound in the yarn.

Defect classification: 1 point = 0”-3”, 2 points = 3”-6”, 3 points = 6”-9”, 4 points > 9”

4. Coarse Yarn

A coarse yarn is a thicker yarn than other neighboring yarns.

Cause:

A particularly thick spun yarn is formed due to a failure of the draft mechanism or its poor performance.

Defect classification: 1 point = 0”-3”, 2 points = 3”-6”, 3 points = 6”-9”, 4 points > 9”

5. Broken Pick

One or more weft yarns are missing from a certain length of fabric.

Cause:

1. The filling yarn breaks in weaving.
2. The weft is heavily knotted or has fly yarns, which will cause the breakage of the weft when it’s dismantled.

 Defect classification: 1 point = 0”-3”, 2 points = 3”-6”, 3 points = 6”-9”, 4 points > 9”

6. Broken End

During weaving process a breakage of the single or multiple warp yarns can result in a broken end – a state with no warp at certain lengths of the fabric.

Cause:

1. The warp is interrupted in weaving
2. The self-stop device is out of order
3. The warp is not connected and the weaving continues

Defect classification: 1 point = 0”-3”, 2 points = 3”-6”, 3 points = 6”-9”, 4 points > 9”

7. Crack

A number of parallel warp or weft yarns sloped in an arc to form gaps.

Cause:

After such defects as a large coarse knot, warp shrinkage, weft shrinkage, etc., are removed, the adjacent warp or weft is not combed and closed with a steel comb, which results in a fabric crack.

Defect classification: 1 point = 0”-3”, 2 points = 3”-6”, 3 points = 6”-9”, 4 points > 9”

8. Dropped stitches

In knitted fabric, if the distance between two rows of loops is greater than usual – it is called dropped stitches. The line segment connecting the two lateral loops tends to be straight, forming holes. If pulled apart, the fabric can disintegrate.

Cause:

1. During production of knitted fabric, if the yarn didn’t thread in the needle, it would result at minimum in one row of loops.
2. Broken or malfunctioning needle

Defect classification: 4 points

9. Off-center printing

Printing deviation, off-center printing, presence of white non-colored parts – are defects of the printing stage of fabric production.

Cause:

1. When printing patterns of more than two colors or the relative position of the printing plate was not aligned.

Defect classification: 1 point = 0”-3”, 2 points = 3”-6”, 3 points = 6”-9”, 4 points > 9”

10. Oil stain

Oil stains on fabric are defects of the production and transportation of fabric.

Cause:

1. Machinery lubricating oil splashes on the fabric during weaving or printing and dyeing finishing process.
2. Oil and grease contamination of the product during transportation.

Defect classification: 1 point = 0”-3”, 2 points = 3”-6”, 3 points = 6”-9”, 4 points > 9”

As you can see, usually the main causes of fabric defects are due to poor equipment maintenance or a poor production environment. In order to solve the mentioned problems, ensure proper maintenance and cleaning of machines, as well as the factory environment.

The factory should set up a production maintenance schedule and follow it in order to prevent machinery failures and future product defects. Thus, when finding a factory to produce your fabrics, choose to conduct a factory audit on it to ensure the production line equipment is in use and is duly maintained.

V-Trust can help to conduct a product inspection and factory audit of your fabric supplier in China, India, Vietnam, Bangladesh and Malaysia. Our full-time inspectors and auditors will help to spot the non-conformities of your fabrics to ensure the quality of your goods and ultimately your reputation.

For more information concerning quality control, please feel free to contact us at info@v-trust.com