spinning & yarn fault
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SPINNING & YARN FAULTS
Prepared By : Mazadul Hasan sheshirID: 201000040000813th Batch Wet Processing Technology Email: mazadulhasan@yahoo.comSoutheast University
Southeast University Department Of Textile Engineering
I/A 251,252 Tejgaon Dhaka Bangladesh
Prepared By :
YARN FA
ULT
LOW COP CONTENTYarn content in the cop is less
1
EFFECT Efficiency loss in ring frame
• Drop in winding efficiency • More knots for a given length of wound yarn
CAUSES Under utilisation 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 teeths/movment in the ratchet wheel Spinning empties wall thickness is high
RECTIFICATION Optimum chase length, coil spacing and wall thickness of empy 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
SLUBSAn abnormally thick place or lump in yarn showing less twist at that
place.
2
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 individualisation at cards to be achieved. 5. Optimum top roller pressure &back zone 6. Setting at ring frame to be maintained.
Yarn containing rolled fibre mass, which can be clearly seen on black board at close distance; measurable on Uster imperfection Indicator.
NEPS
3
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 Accumalation 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 individualisation at cards to be achieved.
Yarn with kinks(twisted onto itself)due to insufficient tension after twisting
SNARL
4
EFFECT Entanglement with adjacent ends causing a break
• Damaged fabric appearance • Shade variation in dyed fabrics • Improper meshing of gear wheels • Mixing of cottons varying widely in fiber lengths and use of immature
cottons
CAUSES Higher than normal twist in the yarn Presence of too many long thin places in the yarn
RECTIFICATION Optimum twist to be used for the type of cotton processed
1. Drafting parameters to minimise thin places in the yarn to be adopted
2. The yarn to be conditioned
3. Correct tension weights and slub catcher settings to be employed at
winding
Measurable by Uster Imperfection Indicator and observable on appearance
THICK AND THIN PLACES
5
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 individualisation at cards to be achieved. 4. Correct spacers to be utilised
Yarn which is weak indicating lesser twist
SOFT YARN
6
EFFECT:
More end breaks in subsequent processes
• Shade variation in dyed fabrics
CAUSES: Slack tapes dirty jockey pulleys
Improper bobbin feed on the spls
Less twist in the yarn
Bad clearing at the travellar
RECTIFICATION:Vibration of bobbins on the spindles to be avoided
1. Proper yarn clearing to be ensured
2. Periodic replacement of worn rings and travellars to be effected
Yarn stained with oil
OIL STAINED YARN
7
EFFECT Damaged fabric appearance
• Occurrence of black spot in fabric
CAUSESCareless oil in the moving parts,over head pulleys etc
Piecings 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 utilised for material transportation
Very small snarl-like places in the yarn which disappear when pulled with enough tension or Yarn with spring –like shape
CRACKERS
8
EFFECT More breaks in winding
• More noticable 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
Unduly thick piecing in yarn caused by over End piecing
BAD PIECING
9
EFFECT
More end breaks in subsequent process
• Increase in hard waste
CAUSES Wrong method of piecing and over end piecing
Twisting the ends instead of knotting
RECTIFICATION
Tenters to be trained in proper methods of piecing
1. Separators to be provided
2. Excessive end breaks in spinning to be avoided
Slub in the yarn stained with oilOILY SLUB
10
EFFECT More end breaks in the ensuring process
• Damaged fabric appearance
• Shade variation in dyed fabrics
CAUSES Accumulation of oily fluff on machinery parts
Poor methods of lubrication in preparatory processes
Negligence in segregating the oily waste from process waste
RECTIFICATION
Yarn contact surfaces to be kept clean
1. Oilers to be trained in correct procedures of lubrication
2. Proper segregation of oily waste from process waste
Presence of black specks of broken seeds, leaf bits and trash in yarnKITTY YARN
11
EFFECT
Damaged fabric appearance
• Production of specks during dyeing
• Needle breaks during knitting
• Poor performance during winding
CAUSES Ineffective cleaning in Blow room and cards
Use of cottons with high trash and too many seed coat fragments
RECTIFICATION
Cleaning efficiency of blow room and cards to be improved
1. Optimum humidity in the departments to be ensured
Protrusion of fibre ends from the main yarn structureHAIRINESS
12
EFFECT More end breaks in winding • Uneven fabric surface • Beads formation in the fabric in the case of polyester/cotton blends
CAUSES Use of cottons differing widely in the properties in the same mixing Use of worn rings and lighter travellars
Maintaining low relative humidity, closer roller settings and very high spindle speeds
RECTIFICATION
Use of travellars of correct size and shape and rings in good condition to be
ensured
1. Periodic replacement of travellars and suitable
2. Roller settings to be maintained
3. Optimum relative humidity to be maintained in the spinning room
4. Wide variation in the properties of cottons used in the mixing to be
avoided
Metallic parts, jute flannel and other similar foreign matters spun along with yarn
FOREIGN MATTERS
13
EFFECT
Breaks during winding
• Formation of holes and stains in cloth
• Damaged fabric appearance
CAUSES Improper handling of travellers
Improper preparation of mixings
RECTIFICATION Removal of foreign matters(such as jute fibres,colour cloth bits) to be ensured during preparation of mixing
1. Installation of permanent magnets at proper
2. Places in blow room lines to be ensured
Fly or fluff either spun along with the yarn or loosely embedded on the yarn
SPUN IN FLY
14
EFFECT
More breaks in winding
CAUSES Accumulation of fluff over machine parts
Fanning by workers
Failure of over head cleaners
Malfunctioning of humidification plant
RECTIFICATION
Machinery surfaces to be kept clean by using roller pickers
1. Fanning by workers to be avoided
2. Performance of over head cleaners and humidification plants to
be closely monitored
It is a double yarn which one yarn is straight and other is coiled over it
CORK SCREW YARN
15
EFFECT
Breaks during winding
•Causes streaks in the fabric
CAUSES Feeding of two ends (instead of one ) in ring frame
Lashing -in ends in ring frame
RECTIFICATION
Tenters are to be trained in piecing methods(or) practices
1. Pneumafil ducts to be kept clean and properly set
Coils of yarn coming out of the ring cops in bunches at the time of unwinding
SLOUGH OFF
16
EFFECT
Increase in end breaks
• Higher yarn waste
CAUSES Improper ring rail movement Worn builder cam Loose package and excessive coils in the package Soft build of cops Improper empties fit on the spindles and slack tapes
RECTIFICATION
Ring rail movement to be set right
• Optimum ratio of winding: bindings coils and optimum chase
length to be maintained
Damaged layers on the surface of the ring cops
RING CUTS
17
EFFECT
Excessive breaks during winding
• More hard waste at winding
CAUSES Spindle or empty cops wobbling
Use of lighter travellers snd incorrect ratchet wheel
Movement of spindles to the rings not concentric
RECTIFICATION
Worn spindles to be replaced
1. Improper fit of empty cops with spindles to be avoided
2. Gauging of spindles with rings to be properly carried out
3. Use of right type travellar and ratchet wheel to be ensured
Step-like appearance of the cop
IMPROPER BOBBIN BUILD
18
EFFECT Slough-off during doffing/winding
• More breaks during unwinding(due to slough off) • Higher hard waste in winding
CAUSES Improper combination of ratchet and pawl
Jerky ring rail movement(pocker rod movement to check)
RECTIFICATION Ratchet and Ratchet/pawl movement to be accurately arrived at taking into consideration
1. Count of yarn, ring dia and chase length
2. Lubrication of pocker rods at appropriate interavels to be carried
out
Ends not laid properly on the cone at reversal of yarn path
STITCHING ON CONE
19
EFFECT More end breaks in the subsequent process
• Excessive yarn waste
CAUSES Vibrating and wrongly set cone holder
Yarn coils wrapped round the base of cone holder
Traverse restrictors fixed at incorrect position
Improper alignment of tension brackets with the drum
RECTIFICATION Maintenance cone winders to be good
1. Cone holder settings and alignment of tension
2. Brackets with drum to be carried out as frequently as possible
Formation of ribbon like structure on the circumference of the cone
RIBBON WOUND CONE
20
EFFECT
High level of slough off during unwinding
• Excessive yarn waste
• Uneven dye pick up in the case of dye packages
CAUSES Winding spindle not revolving freely
Cone holders incorrectly set
Defective settings of cam switch
Lint accumulation in builder cam groove
RECTIFICATION
Over hauling of cone winders to be periodically carried out
1. Anti ribboning mechanism to be checked at frequent interval
2. Free movement of the cone holders to be ensured by proper
lubrication
Unduly soft structure of cone
SOFT BUILD CONE
21
EFFECT
Overall density of package is lower
• Soft packing either at the base or at the nose of cones
CAUSES Improper alignment of winding spindle to the winding drum
Insufficient unwinding tension
Inadequate cradle loading
RECTIFICATION
Unwinding tension to be maintained at 6 to 8% of single yarn strength
1. Cradle pressure to be maintained to the optimum level
Cones which are tightly built at centre, presents a shape of bell
BELL SHAPED CONE
22
EFFECT
Excessive breaks during subsequent processes
CAUSES High yarn tension during winding
Cone holders incorrectly set to the winding drum
Damages in paper cone centre
RECTIFICATION
Quality of cones to be checked at that time of procurement
1. Optimum unwinding tension to be maintained
Bulging of bunches of the yarn at the nose of the cones
NOSE BULGING
23
EFFECT Slough during warping/unwinding
• Excessive yarn waste in next process
CAUSES Improper setting of cone holders to the winding drum
Damaged nose of the paper cones
RECTIFICATION Periodical inspection of settings in winding machines
1. Tenters to be instructed to adopt correct work practices
2. Avoiding usage of damaged paper cones
Collapse of the structure of the cone(paper cone)itself
COLLAPSED CONE
24
EFFECT
Use of poor quality /damaged paper cones
• Poor system of material handling
• Maintaining non optimum unwinding tension
CAUSES Use of poor quality/damaged cones
RECTIFICATION
Using of poor quality/damaged paper cones should be avoided
1. Winding tenters should be trained by proper work methods
2. Proper material handling devices such as cone transport trolleys
to be used
3. Cone inserts to be used for paper cones
BLOW ROOM FAULT
Faults: miss-shaped laps.
Remedy: •If the censity of cotton across the width of the laps is constant ,wedge
shaped laps can still occur due to unequal pressure on side of the
calendar r/r.
•Pressure should be equal on both sides.
Faults: split laps. Remedy:•If lap licking at the card persists, it can be prevented by feeding roving
into the lap sheet as it is formed at the lap end or by use of lap r/r.
Faults: Poor cleaning efficiency.Remedy:
•In the m/c cleaning efficiency is affected by grid bar to beater settings,
better speeds, condition of beater blade edges and beater bars, fan speed
and m/c cleanliness.
•Appropriate stapes have to be taken.
Faults: Neps FormationRemedy:
•The paddle regulator mechanism and cone drum drive should be kept in
good working order.
CARDING FAULT
Faults: neppy web.Remedy:• The m/c made neps may be due to an excessive number of immature fibres in the cotton or to poor settings and maintenance. Which should be properly maintained.
Raw materials:•Checking that the belts are correctly mixed according to micronaire value and fibre bundle strength.•Percentage of wastage should be maintained accordingly.
Faults: cloudy web.Remedy:
•Correct settings of back sheet.
•Poor condition of wire with patches missing, damaged or rubbed will have
the same results which should be maintained.
Faults: Irregular sliver.Remedy:•Any eccentric r/r, incorrect undergrid settings, rubber wire across the eccentric r/r settings should be on the points.
DRAWFRAMES FAULT
Faults: fine sliver.Remedy:
• All drawframe stop mechanism should be regularly tested.
Faults: irregular sliver.Remedy:
• Checking top and bottom r/r, top spinning pressure and r/r settings
and taking suitable action.
• Also checking that sliver is not being reserved.
COMBERS FAULT :
Faults: Neppy waste.Remedy:
•Top combs and cylinders should be examined daily because damaged
cylinder wire/needles and top com needles can cause flocking.
Faults: Long fibers in waste.Remedy:
There are a number of comber settings and timings which will cause long
fibre to be found in the wastage. They include insufficient of the nippers
during feeding, late closing of the nippers, wide detaching r/r settings
detaching r/r turning back too late which should be properly observed.
Faults: Irregular sliver.Remedy:
• R/R, r/r settings and drafts should be checked.
Faults: Curls.Remedy:
• Correct timing of nippers and detaching r/r, correct penetration
of the top combs and r/r covering.
SIMPLEX FAULT
Faults: Slippings coils.Remedy:
• Attention to finding the correct taper wheel, resetting poker bar and the builder will cure this faults.
Faults: Soft bobbins.Remedy:
• This faults can be prevented by using suitable change wheels. If an odd bobbin is affected this could be due to fine a fine roving or incorrect tensioning.
Faults : Irregular roving.Remedy:
• Simplex m/c are susceptible to this faults and source of the vibration is usually in the gearing or grafting r/r.
Faults: Count and hank variationVariation in hank and count should be monitored and controlled as previously
specified by:
• Regular daily inspection and maintained strict control lap weights, weekly
meter/metre wrappings of scutcher laps, calculating variation and
graphing results.
• Wrapping finisher drawframe sliver every 4 hours and taking immediate
action if results exceed tolerance quality control graphs to be used.
• Daily wrappings of yarn for count, regularity of count, strength and twist.
Assessment of yarn on blackboards.
• Faults have adequately death with earlier in this section under regularity.
RINGFRAME FAULT
Faults: Foreign fibers:Remedy:
• Operatives working in the mixing chamber must be instructed to take out any foreign fibers, string, cloth contaminated with dye or oil.
• Care have to be taken when taking the tare from the bale.
Faults: Twist variation:Remedy:
• Too much twist reduces yarn strength and also makes the yarn brittle and liable to from snarls. Spindle to spindle variation also occurs due to differences in spindle speed as a result of driving tape slippage, misalignment of tapes and spindle bearings or inadequate lubrication which should be maintained properly.
The quality control in spinning has a vital consequences on the
production. In the aspect of textile it is a must to make sure to fulfill
the general requirement of the quality in different stages in spinning.
CONCLUSION:
REFERENCE :
vijayakumhark.tripod.com
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