Yarn Defects
Some of the common defects are:
- Thin spots
- Slubs
- Fishes
- Traveller/cracker
- Spun in
- Piecing
- Nep
Slubs
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
- Machine surfaces to be maintained clean.
- Proper functioning of roller clearers to be ensured.
- Broken teeth gear wheel to be avoided and proper meshing to be ensured.
- Better fiber individualization at cards to be achieved.
- Optimum top roller pressure &back zone
- Setting at ring frame to be maintained.
Neps
EFFECT
- Damaged fabric appearance
- Shade variation in the 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
- Machine surfaces to be maintained clean.
- Proper functioning of roller clearers to be ensured.
- Broken teeth gear wheel to be avoided and proper meshing to be ensured.
- Better fiber individualization at cards to be achieved.
Snarl
EFFECT
- Entanglement with adjacent ends causing a break
- Damaged fabric appearance
- Shade variation is dyed fabrics
- The improper meshing of gear wheels
- Mixing of cotton varying widely in fiber lengths and use of immature cotton
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
- Drafting parameters to minimize thin places in the yarn to be adopted
- The yarn to be conditioned
- Correct tension weights and slub catcher settings to be employed at winding
Thick and thin places
EFFECT
- Eccentric top and bottom rollers
- Insufficient pressure on top rollers
CAUSES
- Worn and old aprons and improper apron spacing
- The improper meshing of gear wheels
- Mixing of cotton varying widely in fiber lengths and use of immature cotton
RECTIFICATION
- Eccentric top and bottom rollers to be avoided
- Top arm pressure checking schedules to be Maintained strictly
- Wide variation in the properties of cotton used in the mixing to be avoided
- Better fiber individualization at cards to be achieved.
- Correct spacers to be utilized
Soft Yarns
EFFECT:
- More end breaks in subsequent processes
- Shade variation in dyed fabrics
CAUSES:
- Slack tapes dirty jockey pulleys
- Improper bobbin feed on the spools
- Less twist in the yarn
- Bad clearing at the traveler
RECTIFICATION:
- The vibration of bobbins on the spindles to be avoided
- Proper yarn clearing to be ensured
- Periodic replacement of worn rings and travelers to be effected
Oil Stained Yarns
EFFECT
- Damaged fabric appearance
- Occurrence of black spot in the fabric
CAUSES
- Careless oil in the moving parts, overhead pulleys, etc
- Piecing made with oily or dirty fingers
- Careless material handlings
RECTIFICATION
- Appropriate material handling procedures to be followed
- Oilers to be trained in the proper method of lubrication
- Clean containers to be utilized for material transportation
Crackers
EFFECT
- More breaks in winding
- More noticeable in polyester and cotton blended yarns
CAUSES
- Mixing of cotton of widely differing staple length
- Closer roller settings
- Eccentric top and bottom rollers
- Nonoptimum temperature and relative humidity in the spinning shed
- Over spinning of cotton
RECTIFICATION
- Optimum top roller pressure to be maintained
- Mixing of cotton varying widely in fiber length to be avoided
- Use of optimum roller settings
- Use of properly buffed rollers free from eccentricity to be ensured
Bad Piecing
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
- Separators to be provided
- Excessive end breaks in spinning to be avoided
Oily Slubs
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
- Oilers to be trained in correct procedures of lubrication
- Proper segregation of oily waste from process waste
Kitty Yarns
EFFECT
- Damaged fabric appearance
- Production of specks during the dyeing
- Needle breaks during knitting
- Poor performance during winding
CAUSES
- Ineffective cleaning in Blow room and cards
- Use of cotton with high trash and too many seed coat fragments
RECTIFICATION
- Cleaning efficiency of blow room and cards to be improved
Optimum humidity in the departments to be ensured
Hairiness
EFFECT
- More end breaks in winding
- Uneven fabric surface
- Beads formation in the fabric in the case of polyester/cotton blends
CAUSES
- Use of cotton differing widely in the properties in the same mixing
- Use of worn rings and lighter travelers
- Maintaining low relative humidity, closer roller settings, and very high spindle speeds
RECTIFICATION
- Use of travelers of correct size and shape and rings in good condition to be ensured Periodic replacement of travelers and suitable
- Roller settings to be maintained
- Optimum relative humidity to be maintained in the spinning room
- Wide variation in the properties of cotton used in the mixing to be avoided
Foreign Matters
EFFECT
- Breaks during winding
- Formation of holes and stains in cloth
- Damaged fabric appearance
CAUSES
- Improper handling of travelers
- Improper preparation of mixings
RECTIFICATION
- Removal of foreign matters(such as jute fibers, color cloth bits) to be ensured during the preparation of mixing
- Installation of permanent magnets at proper
- Places in blow room lines to be ensured
Spun in fly
EFFECT
- More breaks in winding
CAUSES
- Accumulation of fluff over machine parts
- Fanning by workers
- Failure of overhead cleaners
- Malfunctioning of humidification plant
RECTIFICATION
- Machinery surfaces to be kept clean by using roller pickers
- Fanning by workers to be avoided
- Performance of overhead cleaners and humidification plants to be closely monitored
Cork Screw Yarns
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
- Pneumafil ducts to be kept clean and properly set
Slough Off
EFFECT
- Increase in end breaks
- Higher yarn waste
CAUSES
- Improper ring rail movement
- Worn builder cam
- Loose package and excessive coils in the package
- Improper empties fit on the spindles and slack tapes
RECTIFICATION
- Ring rail movement to be set right
- The optimum ratio of winding: bindings coils and optimum chase length to be maintained
Ring cuts
EFFECT
- Excessive breaks during winding
- More hard waste at winding
CAUSES
- Spindle or empty cops wobbling
- Use of lighter travelers and incorrect ratchet wheel
- Movement of spindles to the rings not concentric
RECTIFICATION
- Worn spindles to be replaced
- Improper fit of empty cops with spindles to be avoided
- Gauging of spindles with rings to be properly carried out
- Use of right type traveler and ratchet wheel to be ensured
Improper bobbin build
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(proper rod movement to check)
RECTIFICATION
- Ratchet and Ratchet/pawl movement to be accurately arrived at taking into consideration
- Count of yarn, ring dia, and chase length to be taken care off
Stitching on Cone
EFFECT
- More end breaks in the subsequent process
- Excessive yarn waste
CAUSES
- Vibrating and wrongly set cone holder
- Yarn coils wrapped around the base of the cone holder
- Traverse restrictors fixed at an incorrect position
- Improper alignment of tension brackets with the drum
RECTIFICATION
- Maintenance cone winders to be good
- Cone holder settings and alignment of tension
- Brackets with the drum to be carried out as frequently as possible
Ribbon wound cone
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 the builder cam groove
RECTIFICATION
- Overhauling of cone winders to be periodically carried out
- Anti ribboning mechanism to be checked at a frequent interval
- Free movement of the cone holders to be ensured by proper lubrication
Soft build cone
EFFECT
- The 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 Cradle pressure to be maintained to the optimum level
Bell Shaped cone
EFFECT
- Excessive breaks during subsequent processes
CAUSES
- High yarn tension during winding
- Cone holders incorrectly set to the winding drum
- Damages in paper cone center
RECTIFICATION
- Quality of cones to be checked at that time of procurement
- Optimum unwinding tension to be maintained
Nose Bulging
EFFECT
- Slough during warping/unwinding
- Excessive yarn waste in the next process
CAUSES
- Improper setting of cone holders to the winding drum
- The damaged nose of the paper cones
RECTIFICATION
- Periodical inspection of settings in winding machines
- Tenters to be instructed to adopt correct work practices
- Avoiding the usage of damaged paper cones
Collapsed cone
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
- Winding tenters should be trained by proper work methods
- Proper material handling devices such as cone transport trolleys to be used
- Cone inserts to be used for paper cones
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