This document discusses different types of yarn faults, including: 1. Yarn content in the cop being less, causing efficiency loss and more knots. This can be caused by underutilization of bobbin height or improper ratchet settings. 2. Slubs, which are thick lumps showing less twist. This can damage fabrics and cause shade variations. Poor carding, machine dirtiness, and drafting issues can cause slubs. 3. Neps, which are rolled fiber masses visible on black boards. This also damages fabrics. Machine cleaning, carding, and drafting are important to prevent neps.

2. Submitted by: Asif Ahmed Tonmoy
ID: 131-23-3505 ; Sec: D(L 3T1)
Assignment topic: Different kinds of yarn faults.
Submitted to:
Lecturer
Daffodil International University
Nadim Haider Maruf

3. Yarn faults
The defects of yarn is called Yarn faults.
When an uneven place or impurities or any
other lack of minimum quality is found in a yarn
is called yarn defects or faults.

5. Yarn content in the cop is less

6. EFFECT
Efficiency loss in ring frame
•Drop in winding efficiency
•More knots for a given length of wound yarn
CAUSES
Under utilization of bobbin height
Lower number of coils /inch
Higher chase length
Cop bottom bracket properly not set
Improper selection of ratchet
Ratchet pawl pushing number of teeth's /movement in the ratchet wheel
Spinning empties wall thickness is high
RECTIFICATION
Optimum chase length, coil spacing and wall thickness of empty cops tobe ensured
1. Ratchet/pawl movement to be properly set
2. Free space of only 7.5mm to be maintained at the top and bottom of the
cop
3. Free space only 0.75mm only to be maintained between full cops and the
ring

7. An abnormally thick place or lump in yarn showing less twist at that
place.

8. EFFECT
More end breaks in the next process.
 Damaged fabric appearance.
 Shade variation in dyed fabrics.
CAUSES
Accumulation of fly and fluff on the machine parts.
Poor carding.
Defective ring frame drafting and bad piecing
Improperly clothed top roller clearers.
RECTIFICATION
1. Machine surfaces to be maintained clean.
2. Proper functioning of pnemafil /roller clearers to be ensured.
3. Broken teeth gear wheel to be avoided and proper meshing to be
ensured.
4. Better fiber individualization at cards to be achieved.
5. Optimum top roller pressure &back zone
6. Setting at ring frame to be maintained.

9. Yarn containing rolled fibre mass, which can be clearly seen on
black board at close distance; measurable on Uster
imperfection Indicator.

10. EFFECT
Damaged fabric appearance
•Shade variation in the dyed fabrics
•An abnormally thick place or lump in yarn showing less twist at that place
is called slubs
CAUSES
Accumulation of fly and fluff on the machine parts
Poor carding.
Defective ring frame drafting and bad piecing
Improperly clothed top roller clearers.
RECTIFICATION
Machine surfaces to be maintained clean.
1. Proper functioning of pnemafil/roller clearers to be ensured.
2. Broken teeth gear wheel to be avoided and proper meshing to be
ensured.
3. Better fiber individualization at cards to be achieved.

11. Measurable by Uster Imperfection Indicator and observable on
appearance

12. EFFECT
Eccentric top and bottom rollers
•Insufficient pressure on top rollers
•Worn and old aprons and improper apron spacing
•Improper meshing of gear wheels
•Mixing of cottons varying widely in fiber lengths and use of immature cottons
CAUSES Eccentric top and bottom rollers
Insufficient pressure on top rollers
Worn and old aprons and improper apron spacing
Improper meshing of gear wheels
Mixing of cottons varying widely in fibre lengths and use of immature cottons
RECTIFICATION
Eccentric top and bottom rollers to be avoided
1. Top arm pressure checking schedules to be Maintained strictly
2. Wide variation in the properties of cottons used in the mixing to be avoided
3. Better fiber individualization at cards to be achieved.
4. Correct spacers to be utilized

13. Yarn which is weak indicating lesser twist

14. EFFECT:
More end breaks in subsequent processes
•Shade variation in dyed fabrics
CAUSES:
Slack tapes dirty jockey pulleys
Less twist in the yarn
Bad clearing at the traveller
RECTIFICATION:
Vibration of bobbins on the spindles to be avoided
1. Proper yarn clearing to be ensured
2. Periodic replacement of worn rings and travellers to be effected

15. Yarn stained with oil

16. EFFECT
Damaged fabric appearance
•Occurrence of black spot in fabric
CAUSES
Careless oil in the moving parts, over head pulleys etc
Piecing's made with oily or dirty fingers
Careless material handlings
RECTIFICATION
Appropriate material handling procedures to be followed
1. Oilers to trained in proper method of lubrication
2. Clean containers to be utilized for material transportation

17. Very small snarl-like places in the yarn which disappear when pulled with
enough tension or Yarn with spring –like shape

18. EFFECT
More breaks in winding
•More noticeable in polyester and cotton blended yarns
CAUSES Mixing of cottons of widely differing staple length
Closer roller settings
Eccentric top and bottom rollers
Non optimum temperature and relative humidity in the spinning
shed
Over spinning of cottons
RECTIFICATION
Optimum top roller pressure to be maintained
1. Mixing of cottons varying widely in fibre length to be avoided
2. Use of optimum roller settings
3. Use of properly buffed rollers free from eccentricity to be
ensured

19. Short thick place