Faults in the Knitted Fabrics (part 3)

FinishingRelated Defects:
Defects caused mainly due to the wrong process parameters are;

1. High Shrinkage
2. Skewing
3. Spirality
4. Surface Hairiness & Pilling
5. Tonal variation
6. Snagging (Sharp points in the dyeing machine or trolley etc)
7. Fold Marks
8. Wet Squeezer Marks
9. GSM variation
10. Fabric Width variation
11. Curling of S.J. Fabrics

DropStitches (Holes)
Definition:
Drop Stitches are randomly appearing small or big holes of the same or different size which appear as defects in the Knitted fabrics.

Hole in fabric

Major Causes:

• High Yarn Tension
• Yarn Overfeed or Underfeed
• High Fabric Take Down Tension
• Defects like Slubs, Neps, Knots etc.
• Incorrect gap between the Dial & Cylinder rings.

Remedies:

1. Ensure uniform yarn tension on all the feeders with a Tension Meter.
2. Rate of yarn feed should be strictly regulated as per the required Stitch Length.
3. The fabric tube should be just like a fully inflated balloon, not too tight or too slack.
4. The yarn being used should have no imperfections like; Slubs, Neps & big knots etc
5. The gap between the Cylinder & the Dial should be correctly adjusted as per the knitted loop size.

Barriness
Definition:
Barriness defect appears in the Knitted fabric in the form of horizontal stripes of uniform or variable width.

Causes:

• High Yarn Tension
• Count Variation
• Mixing of the yarn lots
• Package hardness variation

Remedies:

• Ensure uniform Yarn Tension on all the feeders.
• The average Count variation in the lot should not be more than + 0.3
• Ensure that the yarn being used for Knitting is of the same Lot .
• Ensure that the hardness of all the yarn packages is uniform using a hardness tester.

Streakiness
Definition:
Streaks in the Knitted fabrics appear as; irregularly spaced & sized, thin horizontal lines.

Causes:

• Faulty winding of the yarn packages.
• Yarn running out of the belt on the Pulley

Remedies:

• Winding of the yarn package should be proper.
• The yarn should be running between the belt and around the pulley.

Imperfections
Definition:
Imperfections appear on the fabric surface in the form of unevenly placed or randomly appearing Knots, Slubs & Neps, Thick & Thin places in the yarn.

Causes:

• Big Knots, Slubs & Neps in the yarn, Thick & Thin yarn.

Remedies:

• Specify the quality parameters of the yarns to be used for production to the yarn supplier.