Yarn Faults

Yarn fau fault ltss Types Causes remedies

Staple

yarn defects

arise from raw materials, machinery settings, improper maintenance  RAW MATERIAL: For cotton : immature fibres neps trash, etc For wool : grease suint  veg matters, etc

Filament

yarns

 Defects arise from differences in the morphology  of the polymer rather than from differences in linear density   For man made fibers concentrations of finish oligomers undrawn or improperly drawn segments of  fiber

slub(long thick place)  Abnormally thick place of length 1-4 cm and about 5-8 times larger than average yarn dia showing less twist at that place of the yarn Eff ects

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More end  breaks in the ensuring process Damaged fabric appearance Shade variation in dyed fabrics

Causes 

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Poor individualization of fibers at the card Lack of adequate fibre control in the drafting region  Accumulation of fly and fluff on machine parts Improperly clothed top roller clearers Defective RF drafting and bad piecing Too close roller setting

Remedies 

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Better opening and cleaning in BR and carding Replace defective aprons Optimum top roller pressure and back zone setting at RF to be maintained Excessive roving twist Broken teeth in gear  wheel to be avoided and proper meshing to be

oily slub Slub in the yarn stained with oil Eff ects

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More end breaks in the subsequent processes Damaged fabric appearance Shade variation in dyed fabrics

Causes 

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Remedies

 Accumulation of oily   Yarn contact surfaces to fluff on machine parts  be kept clean Improper lubrication Proper lubrication and Negligence in segregation segregating the oily   waste from process  waste

Kitty yarn( bakar )  Presence of black specs of broken seeds, leaf bits and trash in yarn. Eff ect

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Damaged fabric appearance Production of specks during dyeing Needle breaks during knitting Poor performance during  winding

cause

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Improper ginning i.e. Seeds broken during ginning Ineffective cleaning in  blow room and cards Use of cotton with high trash and too many  seed coat fragments

remedy  

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Good ginning practices Cleaning efficiency of BR  and cards should be improved. Optimum humidity in the departments should  be ensured

Foreign

matters

 Metallic parts, jute flannel and other similar foreign matter spun along with yarn Eff ects

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Breaks during  winding Formation of holes and stains in the cloth Damaged fabric appearance

Causes 

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Improper handling of  travellers Improper preparation of mixing

Remedies 

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Removal of foreign matters should be ensured during preparation of mixing Installation of  permanent magnets at proper places in BR  lines

Cork

screw yarn

Double yarn in which one yarn is straight and the other is coiled over it. Eff ects

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Breaks during  winding causes streaks in the fabric

Causes 

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Feeding of two ends in the RF Lashing in of ends in RF

Remedies 

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Tenters are to be trained in piecing practice Pneumafill ducts to be kept clean and properly set

Snarl/over

twisted yarn

 Yarn with kinks(twisted onto itself) due to insufficient tension after twisting Eff ects

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Entanglement with adjacent ends causing a  break  Damaged fabric appearance Shade variation in dyed fabrics

Causes

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 Wrong selection of twist  wheel  Wrong selection of  spindle driving pulley  Presence of too many  long thin places in the  yarn

Remedies

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Optimum twist to be used for the type of  cotton processed Drafting parameters to minimize thin places in  yarn to be adopted  Yarn should be conditioned Correct tension weights and slub catcher settings should be employed at  winding

Soft

yarn

 Yarn which is weak indicating lesser twist Eff ects

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More end breaks in subsequent processes Shade variation in dyed fabrics

Causes

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Cord slippage on spindle wharves Improper bobbin feed on the spindles Less twist in the yarn Bad clearing at the traveller

Remedies

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 Vibration of bobbin on the spindle should  be avoided Proper yarn clearing should be ensured Periodic replacement of worn rings and travellers

Oil

stained yarn(daghi)

Oil or stain marks present on the yarn Eff ects

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Damaged fabric appearance Occurrence of black  spots in the fabric

Causes 

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Over flowing of oil from spindle bolster Excessive oil on ring  with intention of  running the traveller smoothly  Improper material storage and handling Piecing made with oily or dirty fingers

Remedies 

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Proper oiling and greasing Proper material storage and handling

Spun in

fly

Fly or fluff either spun along with the yarn or loosely  embedded on the yarn Eff ects

Causes

More breaks in winding

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 Accumulation of fluff  over m/c parts(captured b/w  front drafting rolls and pigtail guide) Fanning by workers Failure of over head cleaners Malfunctioning if  humidification plant

Remedies 

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Machinery surfaces to  be kept clean by use of  roller pickers Fanning by workers avoided Performance of  overhead cleaners and humidification plants should be closely  monitored

Bad

piecing(moree)

Unduly thick piecing in the yarn caused by over end piecing

Eff ects

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More end breakages in subsequent processes Increase in hard waste

Causes 

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 Wrong method of  piecing and over end piecing Twisting the ends instead of knotting Too close roller setting

Remedies 

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Proper piecing Separators should be provided Excessive end  breakages in spg should be avoided

crackers  Very small snarl like places in yarn which disappear when pulled with enough tension or yarn with spring like shape Eff ects

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More breaks in winding More noticeable in P/C blended  yarns

Causes 

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Mixing of cotton of widely  differing staple lengths Closer roller settings Eccentric top and bottom rollers Over spinning of cottons Non optimum temp and RH in the spg shed Long fibers(bridge the nip line in drafting system and disrupt the process)

Remedies 

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Optimum top roller pressure Optimum roller setting Use of properly buffed rollers free from eccentricity to be ensured Mixing of cottons  varying widely in fine length to be avoided

THICK AND THIN Eff ects

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More end breaks in  winding Damaged fabric appearance Poor knitting performance

PLACES

Causes

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Eccentric top and  bottom rollers Insufficient pressure on top rollers  Worn and old aprons and a improper spacing Improper meshing of  gear wheels Mixing of varying length cotton and use of immature cotton

Remedies

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Eccentric top and  bottom rollers to be avoided Top arm pressure checking schedules to maintained strictly  Correct spacers to be utilized

NEPS  Very short fault of more than 200% of the yarn dia Eff ects

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Damaged fabric appearance End breaks in subsequent process

Causes 

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ginning Improper opening in BR  Poor carding due to improper settings Use of low micronaire cottons

Remedies 

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Correct settings and speeds in BR and cards to be maintained Grinding schedules to  be maintained strictly   Avoid immature cotton Use of long cotton

Neps level    

Raw material (bale) : 100 -900 neps/g BR : slightly less than bale Card : 25 -300 neps /g Combing : 7-80 neps /g

Measurement : vary with count ring spg ± 200% yarn dia rotor spg ± 300% yarn dia

BALL

Eff ects

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end breakage in subsequent process

Causes

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 Accumulation of lint (short fibres debris from drafting)on the traveler

Remedies

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Use of over head cleaners

FISHES

Eff ects

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affect fabric appearance

Causes

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Drafting under too dry conditions can cause static electricity to be generated by the sliding fibres

Remedies

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optimum RH should  be maintained

HAIRINESS Protrusion of fibre ends from the main yarn structure Eff ects

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More end breaks in  winding Uneven fabric surface Beads formation in the fabric in the case of P/C blends

Causes 

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Use of cottons differing widely in the properties in the same mixing  Worn rings and lighter traveler Low RH Close roller settings  Very high spindle speeds

Remedies 

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Traveler of correct size and shape Use of rings in good conditions Periodic replacement of traveler Correct roller settings Maintaining Optimum RH  Wide cotton mixing should be avoided