Yarn Formation Techniques

Yarn Defects

Some of the common defects are:

1. Thin spots
2. Slubs
3. Fishes
4. Traveller/cracker
5. Spun in
6. Piecing
7. 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