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Assignment on Yarn Faults

Introduction:
Yarn quality is influenced by numerous varieties of yarn faults that additionally affects the standard of cloth created . throughout the yarn producing method numerous varieties of irregularities square measure generated within the yarn diameter often or at intervals that square measure called yarn faults

Yarn faults

The defects of yarn is termed Yarn faults.
When Associate in Nursing uneven place or impurities or the other lack of minimum quality is found during a yarn is termed yarn defect or yarn fault.

Classifications of faults :

This will provides a close break-up of yarn faults supported the length and dimensions of the faults. There square measure whole twenty three varieties of faults, every fault is known by Associate in Nursing alphabet and variety. The alphabet ‘A’ to ‘G’ indicates the thick yarn faults whereas the letters ‘H’ and ‘I’ represent skinny faults. the quantity one represents a faults of size +100 to +150% over the nominal crosswise within the case of thick place and
-30 to -45% within the case of skinny places. range two suggests that +150 to +250% for thick places and -45 to -75% for the skinny places and then on.

EFFECT potency loss in ring frame

• Drop in winding potency
• More knots for a given length of wound yarn
CAUSES
Under utilization of reel height
 Lower range of coils /inch
 Higher chase length
 Cop bottom bracket properly not set
 Improper choice of ratchet
 Ratchet stop pushing range of teeth’s /movement within the 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 house of solely seven.5mm to be maintained at the highest and bottom of the cop
3. Free house solely zero.75mm solely to be maintained between full cops and also the ring
SLUBS
An abnormally thick place or lump in yarn showing less twist at that place

EFFECT

More finish breaks within the next method.
 Damaged material look.
 Shade variation in bleached materials.
 CAUSES
 Accumulation of fly and fluff on the machine elements.
 Poor carding.
 Defective ring frame drafting and dangerous piecing ü Improperly clothed prime roller clearers.
RECTIFICATION
1. Machine surfaces to be maintained clean.
2. correct functioning of pnemafil to be ensured.
3. Broken teeth of the wheel must be avoided and correct the meshing of tooth.
4. higher fiber secernment at cards to be achieved.
5. Optimum prime roller pressure &back zone vi. Setting at ring frame to be maintained.
NEPS
Yarn containing round of fibre mass, which may be clearly visible on board at off distance; measurable on Indicator Uster state.
EFFECT broken material look
• Shade variation within the bleached materials
• An abnormally thick place or lump in yarn showing less twist at that place is termed slubs

CAUSES Accumulation of fly and fluff on the machine elements
 Poor carding.
 Defective ring frame drafting and dangerous piecing
 Improperly clothed prime roller clearers.

RECTIFICATION
Machine surfaces to be maintained clean.
1. correct functioning of pnemafil/roller clearers to be ensured.
2. Broken teeth wheel to be avoided and correct meshing to be ensured.
3. higher fiber secernment at cards to be achieved.
THICK AND skinny PLACES
Measurable by Uster state Indicator and noticeable on look

EFFECT Eccentric prime and bottom rollers
• Insufficient pressure on prime rollers
• Worn and recent aprons and improper apron spacing
• Improper meshing of substances wheels
• Mixing of cottons varied wide in fiber lengths and use of immature cottons

CAUSES Eccentric prime and bottom rollers
 Insufficient pressure on prime rollers
 Worn and recent aprons and improper apron spacing
 Improper meshing of substances wheels
 Mixing of cottons varied wide in fibre lengths and use of immature cottons

RECTIFICATION
Eccentric prime and bottom rollers to be avoided
1. prime arm pressure checks the schedules must Maintained strogly.
2. Wide range of variation wit properties of cottons to be avoided
3. higher fiber secernment at cards to be achieved.
4. Correct spacers to be utilised
SOFT YARN
Yarn that is weak indicating lesser twist
EFFECT:
More finish breaks in resulting processes
• Shade variation in bleached materials

CAUSES:
Slack tapes dirty jockey pulleys
 Less twist within the yarn
 Bad clearing at the human

RECTIFICATION:
Vibration of bobbins on the spindles to be avoided
1. correct yarn clearing to be ensured
2. Periodic replacement of worn rings and travellers to be accomplished
OIL STAINED YARN
EFFECT broken material look
• Occurrence of plant disease in material

CAUSES Careless oil within the moving elements, over head pulleys etc
 Piecing’s created with oily or dirty fingers
 Careless material handlings

RECTIFICATION acceptable material handling procedures to be followed
1. Oilers to trained in correct methodology of lubrication
2. Clean containers to be utilised for material transportation

CRACKERS
Very little snarl-like places within the yarn that disappear once force with enough tension or
Yarn with spring –like form
EFFECT a lot of breaks in winding
• More noticeable in polyester and cotton integrated yarns

CAUSES mix of cottons of wide differing staple length
 Closer roller settings
 Eccentric prime and bottom rollers
 Non optimum temperature and ratio within the spinning shed ü Over spinning of cottons

RECTIFICATION Optimum prime roller pressure to be maintained
1. mix of cottons varied wide in fibre length to be avoided
2. Use of optimum roller settings
3. Use of properly buffed rollers free from eccentricity to be ensured

4. Use proper inspection system in the all sections of production.

Updated: July 26, 2018 — 9:13 pm

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