“Describe the Sources, Causes, Effects and Remedy of faults in Textile (Yarn, Knitting, Dyeing, and finishing).”
Preliminary
A Fabric Defect is any abnormality in the fabric that hinders its acceptability by the consumer. Defect-Free Fabric: A fabric that exhibits a consistent performance within the boundaries of human use & human view. A Fabric that exhibits a consistent appearance within the human sight boundaries. The world produces over 17 million tons of knitted textiles and apparel – representing one third of the global textile market. Moreover, output is forecast to grow by 25% over the next ten years, reaching more than 21 million tons. Knitwear remains the highest contributor to Bangladesh’s exports growth in the fiscal year (2007-08), according to the Export Promotion Bureau (EPB). It again crossed the target of export registering a 21.19 percent growth in the fiscal year (2007-08), compared with the corresponding period of FY 2006-07. US $4.929 billion was earned from knitwear exports against the target of US$4.899 billion for the period in FY 2007-08.Containing 20% cumulative average growth rate knitwear is now the number one export earning sector in our country. In FY 2006-07 the export of knitwear earning was US$ 4553.60 million which was 19.30% more than the previous year. Knitwear is the country’s largest single export item and together with woven products export earnings account for over 75 percent.
Knitwear is well ahead of woven exports, as it is able to take advantage of domestically produced inputs such as yarn. This cuts lead time and makes products more attractive to international buyers. In the July-June period of FY 2007-08 woven garment products worth US$4.63 billion were exported, a 10.62 percent up on a year earlier. Meanwhile, total export earnings reached US$12.64 billion during the period in FY 2007-08, posting a 15.33 percent growth over the corresponding period a year earlier.
AIM OF THE PROJECT
To determine the fabric faults in knit processing industries.
To find out the different causes for excess fabric faults in the industries.
To determine the process loss, faults effects & remedy and its parameters in knit fabric processing.
To know about the different processes and environment of the different factories.
To know about various knit fabrics available in the industries.
To summarize the literature related to this project
To know about the different dyestuffs and chemicals used in different factories.
To determine the better process that can provide economic benefits minimizing wastage
To suggest on how to improve productivity.
Effects of faults in textile
In order to understand the problems you face when buying and selling textile products, you need to understand the materials themselves and this is best done by understanding a little about how they are made. The seminar takes you through the basic principles of textile manufacture and deals with how some materials are more prone to certain problems and why. It also explains why some materials are more expensive than others. This course will introduce you to the basic principles of textile material manufacture the differences between fibers and where they come from, how fibers are turned in to the fine twisted structure that is a yarn, looks at weaving, knitting and non-woven and dyeing, printing and finishing.
To establish a uniform method for determining, quantifying and measuring the quality of warp knit electrometric fabrics, and a method for measuring length, width, and other physical properties.
The appearance of a fabric can be greatly affected if the yarn has a sufficiently pronounced periodic component. The severity of the periodic fault can only be estimated if its intensity is quantified. Even though a spectrogram is more reliable than other tools at determining periodicity, it gives only the resolved mass variation, which may not be present in the final yarn when different faults are superimposed. The relative index of irregularity of yarn is considered as a measure of the intensity of a periodic fault of a spun yarn. By correlating the above index with the relative unevenness indices of finished fabrics knitted from yarn samples produced at different levels of roller eccentricity, we have established the threshold value of the relative index of irregularity of yarn which produces worse appearance values in the fabric.
Mass variation in yarn can adversely affect many properties of textile materials such as shade variations and strength. Mass variation can be attributed to the properties of raw materials, inherent short comings in yarn making and preparatory machines, mechanically defective machinery and/or external causes as a result of working conditions and improper housekeeping.
The variation in mass per unit length of yarn comprises three basic types [9], namely (i) irregularity of a completely random nature, (ii) irregularity of a markedly periodic nature, (iii) irregularity of a quasi-periodic nature. Purely random irregularity forms an unavoidable component of total irregularity, so that a minimum achievable random irregularity can be acceptable for apparel usage.
The periodic irregularities which are found in the spun yarns may be the result of machinery defects such as eccentric drafting rollers, variability in the covering of drafting rollers, inaccurately cut or worn-out drafting rollers and the vibration of drafting rollers [3]. Yarns which are affected by any of these defects occurring in the drafting prior to spinning can appreciably affect the yarn and the resulting fabric.
Periodic mass variations in yarn can cause weft bars, diamond barring effects [3], moiré effects, weft stripes or rings in the resulting fabric [8]. Hence, periodic irregularity should not be permitted at all, since it greatly affects the appearance of fabric and must be controlled. However, the presently available tools used to measure the periodicity of mass per unit length variation have limitations. The spectrogram is more reliable compared to other tools for determining periodicity; it works on the principle of Fourier analysis [8], which sets out any function in a series of sine curves. The actual mass variation will be resolved into different sinusoidal waves with different amplitudes and wavelengths. Hence, spectrogram gives only the resolved mass variation, which may not be present in the final yarn when different faults are superimposed.
The main objective of the present work is to understand these limitations and establish supplementary methods for the available tools which are used to measure the periodicity of mass variation, and to suggest new measures to understand the effect of periodic mass variation of yarn on fabric appearance.
Yarn Faults
It is still not possible to produce a yarn without faults for various reasons. Stickiness of cotton can contribute to the formation of thick and thin places. Fly liberation in Ring frame department is one of the major reasons for short faults in the yarn because of the fly gets spun into the yarn. Hence it is not possible to have fault free yarn from rings pinning, it is necessary to have yarn monitoring system in the last production process of the spinning mill. As physical principle for electronic yarn clearing the capacitive and the optical principle have established. Both principles have their advantages in specific applications.
The yarn faults which go into the woven or knitted fabric can be removed at very high costs or can not be removed at all. Therefore the yarn processing industry demands a fault free yarn.
The difference between frequent yarn faults and seldom occurring yarn faults are mainly given by the mass or diameter deviation and size. These faults are monitored by classmate or clearer installation on winding.
» Yarn Faults:
1. Yarn patta.
2. Dirty yarn.
3. Yarn thick & thin.
4. Neps yarn.
5. Contamination yarn.
6. Slub yarn.
7. Dead cotton.
8. Hairiness.
9. Yarn uneven.
10. Spinness double.
11. Bad piecing.
12. Short length of hard
twist.
13. End missing.
14. Irregular drafting.
15. Roller lapping.
16. Irregular selvedges.
17. Fuzzing at the tube
wheel bore.
18. Impurities in the
sliver.
Faults of yarn & their remedies:
1. Yarn Patta:
The term yarn patta in a broad sense coners to missing the lot mixing fiber and wrong the bale management to mixture blow-room M/C to the stage.
Sources & Causes:
• Missing the lot mixing fiber in the spinning mills.
• Wrongthe bale management to mixture.
Effects:
• Uneven dyeing problem.
• May be fabric hole.
• Fabric waste.
• Cost highly.
• Time loss.
Remedy:
• Enzyme the fabric in the dyeing section.
• Major problem, yarn rejected.
2. Dirty yarn:
The yarns which are produced by untidy of the m/c and spinning floor by careless handling are called dirty yarn.
Sources & Causes:
• Improper cleaning of the m/c.
• To stay dirty in the spinning floor.
• Careless handling.
• Improper storing.
Effects:
• Dirty yarn usage cause to make dirty knitted fabric, Dyeing problem & high cost.
• Dirty fabric cause reduces to the consumer.
• Time loss.
• Stiffness loss of yarn.
Remedies:
• Thus wash fastness is improved.
• The rinsed washing broken dirty bonded to the yarn.
• Washing to the wetting agent.
3. Yarn thick &thin:
It is uneven surface of yarn. Yarn surface is is no twisting, Traveler problem and Faulty drafting zone where is thick and twisting in place of thin.
Sources & Causes:
• Where of yarn surface is no twisting that where is thick and twisting in place of thin.
• Traveler problem in the spinning frame.
• Faulty drafting zone.
Effects:
• More rejected of yarn. Costly high Traveler problem in the spinning frame.
• To create knitting, garments & Textile problem.
• Decrease the consumer
Remedy:
• Improve the travelers in the spinning frame.
• Correct the drafting zone before running r/r.
• To tension free from faults.
• To insert twist to the drafted stands of fibers.
4. Neps yarn:
It’s seen as pilling of where yarn surface. To create Twist missing causes.
Sources & Causes:
• Hard cot roller.
• Improper roller pressure.
• Processing faults.
• Twist missing, causes of traveler.
Effects:
• To create knitting, Dyeing and Garments problem.
• Decrease the attraction to Buyers and consumers.
• Less production.
• Cost highly.
Remedies:
• Processing fault will be correct.
• Hard cot roller will be repairing.
• Improve roller pressure.
• Traveller will free from faults.
5. Contamination yarn:
When Others color fibre with sliver & yarn are winding. This is called contamination.
Sources & Causes:
• If others lots fibre with one lot’s fibre be combined.
• To wind at time of yarn twist.
• Others color fibre with sliver & yarn are winding.
Effects:
• Different color show in contamination yarn.
• Fabric wastage & less production in Garments.
• Highly cost.
• Consumer & Buyer are not choose.
Remedy:
• Carefully, if others lot’s fibre with one lots fibre not
be combined.
• To wind with carely at time of yarn twist.
• Others colour fibre with sliver & yarn are not
winding.
6. Slub yarn:
Sometimes are seeing in yarn surface is more shoft pilling from yarn thick &thin and dust causes.
Sources & Causes:
• To create Slub yarn from yarn thick &thin causes.
• Roller broke in Drafting zone.
• Improper pressure in roller.
• Traveller problem & yarn are not twisting in
place to yarn surface.
• To stay lint in yarn.
Effects:
• Knitting fabric wastage.
• To create line mark, Neps spot in dyeing of slub yarnfabric faults.
• Frequently, yarn breaks.
• Decrease the consumer.
Remedies:
• Improve roller in drafting zone.
• correct pressure in roller running.
• Right the traveller uses.
• Even twisting in place of yarn surface.
7. Dead cotton:
Dead cottons are made of the dead fibre with yarn winding.
Sources & Causes:
• To wind the dead fibre with yarn.
• To wind the perish fibre with sliver.
• Rightly fibre lots are not select.
• Causes of low quality fibre.
Effects:
• Dead fibre has no affinity to dyes & chemical.
• Uneven shade problem.
• Dead fibre spot problem.
• Fabric wastage.
• Less production.
• More time.
Remedy:
• Minor problem to remove by enzyme.
• Major problem to rejected.
• No wind the perish fibre with yarn.
• Carefully, fibre lots will be selected.
8. Hairiness:
Yarn hairyness will make from more the short fibre used and yarn friction.
Sources & Causes:
• Traveller broken to stay.
• Decrease guide & friction causes.
• More the short fibre.
• Improper drafting zone.
Effects:
• To create hairiness, loams smooth, out of projecting fibre & hairy fibre of yarn surface.
• Cost highly.
• Increase the process.
• More time.
Remedy:
• Traveller will be right.
• Improve guide.
• Decrease friction.
• Repairs the drafting zone.
9. Yarn uneven:
Yarn will make thick & thin of yarn surface from the set- up improper tension of yarn & sliver.
Sources & Causes:
• To stay roller broke in drafting zone.
• Decrease the drafting front roller & to create thick & thin of yarn surface.
• Improper pressure in roller.
• To set-up improper tension of yarn & sliver.
Effects:
• Frequently, yarn break in knitting.
• To fall of obstruct guide path to yarn.
• To create uneven dyeing of fabric.
• May be fabric hole.
Remedies:
• Minor problem causes, roller repairs in drafting zone.
• Causes major problem, broke roller change.
• Improper pressure in roller.
• proper tension set-up of yarn & sliver.
10. End missing.
When 6 to 8 slivers are doubled it the draw frame one of them may be broken down. So doubling will not be proper & fine sliver will produce.
Sources & Causes:
• If stop motion does not work.
• Carelessness of the operator.
Effects:
• Uneven drawing sliver produced.
• Causes irregular sliver, yarn, knitting, dyeing & garments to major problem.
• Process loss.
• Cost highly.
Remedies:
• Stop motion must be in working condition.
• Operator should be careful.
11. Irregular Drafting.
Irregular Drafting will irregularities in the drawn sliver. So sliver may contain thick thin places, variation in count along the sliver etc.
Sources & Causes:
• Incorrect setting of the drafting rollers for the staple being processed.
• Wrong distribution of draft in the drafting zone.
• Roller variation.
• Nip movement due to eccentric rollers.
• Roller slip.
Remedies:
• Correct roller setting.
• Correct distribution of draft.
• Correct bore in the gears.
• Roller slip should be prevented.
• Roller weighting should be checked.
12. Roller lapping.
When sliver passes through the rollers sometimes the fibers are snarls with the roller specially bottom roller. This is roller lapping.
Sources & Causes:
• Oil on the roller covering.
• Cracked roller surface.
• Roller flutes contains wax, broken leaf etc.
• Excessive relative humidity percentage.
• Rough calendar rollers & wax on their surfaces.
Remedies:
• The roller coverings should be free from oil & wax.
• The coverings should be well varnished.
• Correct relative humidity percentage.
• Adjust correct the roller weighting.
13. Irregular Selvedges.
Sources & Causes:
• Insufficient weighting of the top rollers.
• Certain classes of cotton are also liable to give irregular selvedges.
• Irregular roller surface speed.
Remedy:
• The weight releasing motion should be checked to ensure that the weights are clear of the weight bar.
• Correct the roller weighting.
14. Fuzzing at the tube wheel bore.
Sources & Causes:
• Impurities or roughness in the tube wheel bore.
Remedies:
• Polish the bore.
15. Fuzzing at the front roller.
Sources & Causes:
• Higher front roller speed for combed sliver where greater parallelism & straightening are achieved.
Remedy:
• Reduce front roller speed to 120 ft/min on tradition draw frame.
16. Impurities in the sliver.
Sources & Causes:
• Insufficient cleaning occasioned by incorrect setting of the various clearers.
• Worn clearer clothes.
Remedy:
• The clearer settings & the condition of the cloth should be checked.
Knittimg Faults
The knitting defect due to the knot is almost the knitting hole caused by the end breakage in plain-weft knitting zone. The end breakage occurs near the knot on the take-down side. The end breakage rate increases together with the increase of the depth of stitch draw, the input tension, the take-down weight, the machine gauge, the coefficient of yarn friction, the step length of cam, and the machine speed. But the increase of the cam angle decreases the end breakage rate.
Shade variation in knitted fabrics is an issue of concern. It could be during dyeing and finishing. Mixing could be a suspect. The problem can be machine related or material related.
q Visible, some knitting faults to below:
1. Knitting hole.
2. Loop.
3. Star mark.
4. Set-up.
5. Oil spot.
6. Oil mark.
7. Missing yarn.
8. Variation..
10. Soiled Yarn.
11. Needle mark.
12. Sinker mark.
13. Needle broken.
14. Bowing.
15.Strap line.
16.Grill line.
17.Hard yarn.
18.Rough yarn.
Knitting faults:
- Knitting hole:
It will create to needle broken, needle bent and fabric GSM is high & Low etc. Caused by broken needle.
Sources & Causes:
• Needle broken of knitting m/c.
• Needle bent causes.
• Yarn count range comparison, if fabric GSM is high & Low.
• Dirty in needle place of knitting m/c.
Effects:
• Fabric is hole.
• Knit fabric wastage in Garment section.
• Less apparel production.
• Highly cost.
Remedy:
• Needle change of knitting m/c.
• Do right the needle bent.
• Dirty in needle place is clean by air gun at Everyday.
• With determined the yarn count make will be determine GSM.
- loop:
It makes to stay needle lace broken.
Sources & Causes:
• Not adjust feeder.
• To stay needle lace broken.
• Yarn tension variable.
Effects:
• To make fabric to network opinion.
• Same mesh fabric effective.
Remedies:
• Rightly feeder adjust.
• Broken needle lace change.
• Proper Tension fixed of yarn.
- Star mark:
Body of needle is seen as star mark.
Sources & Causes:
• Needle broken of knitting m/c running time.
Effects:
• Create star mark hole in knitting fabric.
• More fabric wastage in garment section.
• Less production.
• More time.
Remedy:
• Will be change needle of knitting m/c.
4. Set-up.
Sources & Causes:
• If yarn were not feeding in feeders.
• Yarn was fall to dispute from feeders.
Effects:
• One side of fabric is not texture.
• Less production.
• Fabric wastage in Gar ments section.
• Cost highly.
Remedies:
• Yarn adjust in feeders.
5. Oil spot.
Sources & Causes:
• Extra oil for feeded.
• To stay needle broken.
• Be decay to notch of cylinder cam.
• Be decay to notch of Dial cam
Effects:
• Uneven dyeing to oil sport in knit fabric.
• Fabric wastage in garment section.
• processing cost highly.
• Time loss.
• Low production.
• Show the oil spot in the fabric.
Remedy:
• Give the extra oil remove.
• Carefully, Do not touch the fabric by oil.
• Change the needle in knitting m/c.
• Change the cylinder &dial cam.
6. Oil mark.
Sources & Causes:
• To be decay the needle group &oil comes from needle group in the fabric.
• To be decay the sinker group.
• Cylinder & dial cam were decay.
Effects:
• Show the oil mark in the fabric.
• Fabric wastage.
• More time.
• Cost highly.
• Less production.
Remedy:
• Change the needle in the cylinder knitting m/c.
• Change the sinker group.
• Change the Dial and cylinder cam.
7. Missing yarn:
Occurs in warp knit. Results from wrong fibre yarn (or wrong size yarn) placed on warp. Fabric could appear as thick end or different colour if fibers have different affinity for dye.
Sources & Causes:
• Yarn count is feeding 26s 28 feeder and in the two feeder residue to the yarn count is feeder 28s.
Effects:
• Running shade problem in the dyeing section.
• Reduce the Buyer & Consumer.
• Fabric waste.
• The appeal problem in the garments section.
• Time loss.
Remedies:
• Yarn is feeding of same yarn count in the feeder.
• Drive the fabric for deep color.
=>Barre/Patta:
Occurs in circular knit. Caused by mixing yarn on feed into machine. Fabric will appear to have horizontal streaks.
Dyeing Faults
While dyeing, large volume of dyestuff, thickening agent and small amount of water are used. Many textile chemicals like Dispersing agent, Leveling agent, Acid buffer etc are used during the process. The dyestuff have to be either fermented (for natural dye) or chemically reduced (for synthetic vat and sulfur dyes) before being applied. This makes the dye soluble so that it can be absorbed by the fiber. Direct dyes are water soluble and can be applied directly to the fiber from an aqueous solution. Most other classes of synthetic dyes, other than vat and sulfur dyes, are also applied in this way.
• Dyeing faults:
a. Uneven dyeing.
b. Running shade.
c. Batch to batch shade variation.
d. Patchy dyeing effect.
e. Roll to roll variation or Meter to meter variation.
f. Crease / Wrinkle mark.
g. Dye spot.
h. Softener mark.
i. Fabric hole.
Dyeing faults in the textile:
1.Uneven dyeing.
Sources & Causes:
• Uneven pretreatment (uneven scouring & bleaching).
• Improper color dosing.
• Using dyes of high fixation property.
• Uneven heat-setting in case of synthetic fibers.
• Lack of control on dyeing m/c.
Effects:
• Dyeing process loss.
• Fabric waste in garments section.
• More time.
• Waste of chemical & dyes.
• More water & steam.
Remedy:
• By ensuring even pretreatment.
• By ensuring even heat-setting in case of synthetic fibers.
• Proper dosing of dyes and chemicals.
• Proper controlling of dyeing m/c.
2. Batch to Batch Shade variation:
Sources & Causes:
• Fluctuation of Temperature.
• Improper dosing time of dyes & chemicals.
• Batch to batch weight variation of dyes and chemicals.
• Dyes lot variation.
• Improper reel speed, pump speed, liquor ratio.
• Improper pretreatment.
Effects:
• Dyes & chemical waste.
• Loss the time & temperature.
• Fabric waste for light color.
• Less production per day.
Remedies:
• Use standard dyes and chemicals.
• Maintain the same liquor ratio.
• Follow the standard pretreatment procedure.
• Maintain the same dyeing cycle.
• Identical dyeing procedure should be followed for
the same depth of the Shade.
• Make sure that the operators add the right bulk
chemicals at the same time and temperature in the
process.
• The pH, hardness and sodium carbonate content supply water should check daily.
- Patchy dyeing effect.
Sources & Causes:
• Entanglement of fabric.
• Faulty injection of alkali.
• Improper addition of color.
• Due to hardness of water.
• Due to improper salt addition.
• Dye migration during intermediate dyeing.
• Uneven heat in the machine, etc.
Effects:
• Waste of fabric & color.
• More temperature.
• Time loss.
• Cost highly.
• Damage of fabric strength & stiffness.
• More salt.
Remedy:
• By ensuring proper pretreatment.
• Proper dosing of dyes and chemicals.
• Heat should be same throughout the dye liquor.
• Proper salt addition.
5. Roll to roll variation or Meter to Meter variation:
Sources & Causes:
• Poor migration property of dyes.
• Improper dyes solubility.
• Hardness of water.
• Faulty m/c speed, etc.
Effects:
• Color unaffected of fabric.
• Waste of dyes.
• More time & temperature.
• Cost highly.
Remedies:
• Use standard dyes and chemicals.
• Proper m/c speed.
• Use of soft water.
- Crease mark:
Sources & Causes:
• Poor opening of the fabric rope.
• Shock cooling of synthetic material.
• If pump pressure & reel speed is not equal.
• Due to high speed m/c running.
Effects:
• Uneven dyeing in the place of crease mark to knit fabric.
• Cost high for remove.
• Fabric damage in the place of crease mark.
• Loss the Time, Temperature & chemical.
Remedy:
• Maintaining proper reel sped & pump speed.
• Lower rate rising and cooling the temperature.
• Reducing the m/c load.
• Higher liquor ratio.
6. Dye spot:
Sources & Causes:
• Improper Dissolving of dye particle in bath.
• Improper Dissolving of caustic soda particle in
bath.
Effects:
• Body fabric rejected in the garments section.
• More dye & caustic.
• More fabric damage.
• Less production.
• Cost highly.
Remedies:
• By proper dissolving of dyes & chemicals.
• By passing the dissolved dyestuff through a fine stainless steel mesh strainer, so that the large un-dissolved particles are removed.
- Wrinkle mark:
Sources & Causes:
• Poor opening of the fabric rope.
• Shock cooling of synthetic material.
• High temperature entanglement of the fabric.
Effects:
• Fabric waste for wrinkle mark.
• Cost highly.
• More Time.
• Process loss.
• Less production.
Remedies:
• Maintaining proper reel speed & pump speed.
• Lower rate rising and cooling the temperature.
• Higher liquor ratio.
- Softener Mark:
Causes:
• Improper mixing of the Softener.
• Improper running time of the fabric during application of softener.
• Entanglement of the fabric during application of softener.
Effects:
• Fabric damage in the different place of knit fabric.
• Waste of softener.
• Time loss.
• Less production.
Remedies:
• Maintaining proper reel sped & pump speed.
• Proper Mixing of the softener before addition.
• Prevent the entanglement of the fabric during application of softener.
- Fabric hole.
Sources & causes:
• More acid of knit fabric in the dyeing section.
• Highly acidity.
• Temperature highly.
Effects:
• Damage of the knit fabric.
• Fabric strength, stiffness & comfortable loss.
• Waste of acid.
• Loss Time & Temperature.
Remedy:
• Use standard Acid.
• Proper dosing of Acid.
• Proper Control of dyeing m/c.
• Temperature Control.
• Proper acid addition.
Finishing faults in the Textile:
- Ballooning shape.
Sources & Causes:
• Feed the twist fabric in the squeezer m/c.
• Roller pressure variation.
• Over pick variation.
• RPM variation.
Effects:
• Knit fabric, shape change.
• Process loss.
• Less production.
• Time loss.
• Cost highly.
• May be fabric rejected.
Remedies:
• With carefully, fabric feeding in the squeezer m/c.
• Proper roller pressure & RPM are feed.
• Right the over pick feed.
- Radish shade.
Sources & Causes:
• Increase temperature in dryer.
• Increase the gas pressure.
• Decay the trum plate.
• Improper roller RPM.
Effects:
• Fabric damage may be.
• Decrease the fabric strength, stiffness.
• Process loss.
• Less production.
• Time loss.
Remedies:
• Proper the temperature in dryer.
• Improve the trum-plate.
• Proper the gas pressure.
• Proper roller RPM on the temperature.
- Squeezer mark.
Sources & Causes:
• Improper roller pressure.
• RPM variation.
• Improper over pick.
Effects:
• Roller press mark effect in the fabric.
• More waste of knit fabric.
• More fabric in the garment section.
• Time loss.
• Less production in the proper apparel.
Remedies:
• Proper roller pressure.
• Right the RPM to fixed in the m/c.
• Proper over pick.
4. Dia mark.
Sources & Causes:
• Improper Dia leg.
• Press the leg guide/wheel.
• To decay the leg guide/circle.
Effects:
• To see the line spot in the fabric.
• To major problem of fabric in the cutting section.
• Fabric width loss.
• Fabric consumption short.
Remedies:
• Proper Dia leg feed in the m/c.
• Repairing the Dia leg wheel.
• Proper press the Dia leg circle.
- Dirty spot.
Sources & Causes:
• To stay dirty in the floor.
• Uncarefully labour.
• To stay dirty in the m/c.
Effects:
• More process adhere.
• Cost highly.
• Time loss.
• Less production.
• Decrease the buyer.
Remedies:
• Clean the floor at everyday.
• Carefully labour.
• To clean the m/c per week.
- Compaction /Press mark.
Sources & Causes:
• Compacting roller pressure uneven.
• Improper roller.
• Improper RPM.
• Over pick variation.
• Steam pressure variation.
Effects:
• Fabric damage to press of fabric in place.
• Consumption short in cutting section.
• Time loss.
• Cost highly.
• Less production
Remedies:
• Even compacting roller pressure.
• Proper roller.
• Will be give the right over pick.
• Proper steam pressure & RPM.
- Compacting hole.
Sources & Causes:
• More steam pressure.
• Low roller RPM .
• Uneven roller.
Effects:
• Fabric waste.
• Consumption short.
• Less production.
• Cost highly.
Remedies:
• Proper steam pressure.
• Proper roller RPM.
• Feeding the even roller in compacting m/c.
8. Crease mark.
Sources & Causes:
• RPM variation.
• Uneven over pick.
• Roller pressure variation.
• Improper tension.
• Make be lacra fabric.
Effects:
• Shade variation in place of crease mark.
• Improper quality of knit fabric.
• Decrease the Buyer.
• Fabric rejected.
• Time & production loss.
Remedies:
• Proper roller pressure.
• Even over pick.
• Less lacra fabric use.
• Anti-creasing agent used.
• More softener use.
- Calendaring crease.
Sources & Causes:
• Improper calendar roller pressure.
• Fabric Tension variation.
• More lacra use of knit fabric.
Effects:
• Process loss.
• Decrease the buyer.
• Improper Quality of knit fabric.
• Time loss.
Remedies:
• Proper calendar roller pressure.
• Right the fabric tension.
• Less lacra use.
• More softener use.
10. Oil Spot.
Sources & Causes:
• More oil & grease use the wheel, roller bearing into
place.
• To stay unclean the m/c.
• Be decay the roller.
• Fabric waste.
Effects:
• Process loss.
• Cost highly.
• Time.
Remedies:
• Proper oil & grease use in place of the wheel, Bearing in roller.
• To stay clean the m/c at week.
• Repairing the roller.
11. Improper shrinkage.
Sources & Causes:
• Heavy roller pressure.
• Not over pick in finishing m/c.
• Temperature variation.
• RPM variation.
• Under pick causes.
Effects:
• Buyer rejected the fabric.
• Printing problem in the knit fabric.
• Process loss.
• Time loss.
• Less production.
Remedies:
• Proper roller pressure.
• Must be over pick.
• Proper Temperature.
• Right the RPM fixed.
12. Bowing:
Usually caused by finishing. In knits the course lines lie in an arc across width of goods. Critical on stripes or patterns and not as critical on solid color fabrics.
13. Crease Streak:
Occurs in tubular knits. Results from creased fabric passing through squeeze rollers in the dyeing process. Drop stitches Results from malfunctioning needle or jack. Will appear as holes, or missing stitches.
q Fabric waste% in case of Re-dyeing:
Depending on the type of faults, color, order etc of the dyed batches, decision is taken for re-dyeing. Partial or full stripping is done to remove color first and then dyeing is done according to black or other related dark color. Re-dyeing has impact on profitability and productive time.
q Major causes of re-dyeing in knit industry:
1.Uneven dyeing
2.Shade not OK/Shade variation
3.Running shade/Roll to roll shade variation
4.Dye spots.
| Material | Re-dyeing cost | Re-processing time | Fabric waste% in re-dyed batch |
| 100% Cotton | 100% | 200% | 20 to 30% |
PRECAUTIONS NEED TO BE TAKEN IN INDUSTRIES:
We followed different batches in different factories. There was a variation of fabric fault% in factory to factory. Eventually we realize that fabric fault% in wet processing industries can not be avoided but we can minimize it. Some technical precautions that can minimize fabric faults% in knit industries are summarized below:
q Batching section:
1) Fabric should be equally fed into each nozzle a per batch plan, otherwise there may create problem in speed controlling, for which running shade mark or unleveled dyeing possible.
2) Workers should be careful during batch
Preparation
3) Skilled workers should be employed in this
Section
4) Batch weight must be taken accurately.
5) Cutting fault during batch sewing should be Minimized.
q Dyeing Section:
1) Over scouring must be avoided.
2) In case of scouring, run time should be compatible with
temp.
3) Least amount of caustic should be used for better
scouring.
4) PH of scouring-bleaching must be within 10.5-11.5.
5) Over enzyme treatment must be avoided.
6) Amount of enzyme might be used according to its
strength.
7) Dyeing should be carried out accurately, RFT (Right-first-time) dyeing suggested for the industries because if topping or addition needed to be done then fabric wastage will increase.
8) For checking the shade of the batch, workers should cut the samples from a particular space and take smallest sample as possible.
9) Workers in dyeing section should be skilled and aware of the process losses.
q Finishing Section:
Generally this section is not responsible for any type of process loss.
1) Test roll should not be missed or mixed with other batch. It should be returned in the corresponding batch.
2) Sample cut for GSM check and fastness check should not be too large.
3) The GSM of the dyed fabric should be taken after conditioning of the fabric.
4) The responsibility of workers must be noticed and monitored in the finishing section to reduce fault.
5) Most common finishing problems in the knit industry is softener spot and crease mark. Precaution should be taken during softener application in dyeing and good quality anti-creasing agent should be used in pretreatment and dyeing. Fabric should be unloaded in the trolley through over flowing.
Our realization
1) All the process parameters from scouring to finishing should be followed accurately. Some factories set up process parameters but they are not following these parameters accurately. This practice should be stopped.