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Prepared By : Prepared By : Mazadul Hasan sheshir ID: 2010000400008 13thBatch Wet Processing Technology Email: mazadulhasan@yahoo.com Southeast University Southeast University Department Of Textile Engineering I/A 251,252 Tejgaon Dhaka Bangladesh
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
An 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. 2. 3. Machine surfaces to be maintained clean. Proper functioning of pnemafil/roller clearers to be ensured. Broken teeth gear wheel to be avoided and proper meshing to be ensured. Better fiber individualisation at cards to be achieved. Optimum top roller pressure &back zone Setting at ring frame to be maintained. 4. 5. 6.
Yarn containing rolled fibre mass, which can be clearly seen on black board at close distance; imperfection Indicator. measurable on Uster 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 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 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
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
EFFECT Damaged fabric appearance •Occurrence of black spot in fabric CAUSES Careless 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 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
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
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 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
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 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 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 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 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
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
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 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 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
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 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
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
