Problems & Remedies in Wet Processing of 100% Cotton (Woven)

- Pathik Shroff

PROCESS SEQUENCEGrey Room Shearing Cropping Singeing

Desizing

Scouring

Bleaching

Mercerization

Dyeing 

Printing

Finishing

GREY ROOMSr .no. defects causes Remedies

01 Thick & thin place .

1.Immature fibre .2.Staple length.3.Neps.4.Drafting limitation

1.Selection of raw material.1a.Mature fibre.2.Good staple length.3.Maximum Neps should be removed (carding & combing).4.set Required draft.(no of doubling , speed of drafting roller.)

03 Weft bar Count variationDensity of pick more.

use Less variation of weft count.Required density of weft.

04 End & Pick missing

•Warp stop motion not working on loom at warp break.•Moving empty shuttle•Breakage of weft thread

•Use warp stop motion as per break .•New extra thread joining•Mending.

Weft barMissing Ends & Pick

SHEARING & CROPPING Sr .no. defects causes Remedies01 Cut or

holes damage to fabrics.

1.Presence of metallic particle on fabric.2.Due to abrading action.

1.Use magnetic metal detector in feeding device.1a.Removal of metal particle from grey fabric.2.Covering the emery roll with a piece of cloth which reduce abrading action.

02Rough & uneven surface of fabric.

Inefficient Sharpness of blade.

Grinding to blade & proper position & adjustment of blade

HOLES, CUT

SINGEINGSr .no. Defects Causes Remedies1 Incomplete

singeing1. low flame height2. fast fabric speed3. High Moisture content

1. flame height 4”- 6” 2. Fabric speed 90-120 m/min3. Ensure moisture content should be 6-8%

2 Uneven singeing [lengthways]

1. Change in fabric speed duringSingeing

1. Maintain Uniform fabric speed through outSingeing

3. Thermal damage orReduction in tear strength

1. Too slow fabric speed2. close distance between the fabric and the burner

1. Fabric speed must be set Above 60-70 m/min

2. From 6-8 mm upto 6-20 mm distance betweenthe fabric and the burner

FABRIC BEFORE SINGEING & AFTER SINGEING

DESIZINGSr. No. Defects Causes Remedies1. Incomplet

e desizing1. Inappropriate desizing bath pH

Set pH of bath depend on enzyme type of enzyme pH1. Malt extract 6-7.5 2. Pancreatic 6.5-7.53. Bacterial 5.5-7.5

2. Inappropriate desizing bath temperature

Temperature of bath must be 80-95◦ C .

3. Insufficient fabric pick-up

3. Use of wetting Agent

4. Deactivation of enzyme dueto presence of metals or othercontaminants

4a. Use of soft water4b. Use of appropriatesequestering agents

Sr. No. Defects Causes Remedies2 Uneven Desizing 1. Foaming in the bath 1. Use of appropriate

defoamers2. Inappropriate bathtemperature

2. Ensure bath temperature of bath 80-90◦ C

3. Non-uniform washing afterdesgizin

3. Ensure Hot wash at 95◦C for 10-15min Thorough and uniformwashing after desizing

4.Preferential drying of outerlayers of the batch

4a. Covering the batch withpolythene or other suitable sheet

4b. Keep the batch rolling

5.Temperature variationduring digestion

5. Covering the batch withpolythene or other suitable sheet

SCOURINGSr. No. Defects Causes Remedies1. Inadequate

absorbency orHigh residual impurities

Inadequate concentration ofscouring chemicals

Check recipeSodium carbonate - 2-3% owfAnionic detergent - 1-3 g/l

Incompatible or ineffectivesurfactant/wetting agent

Compatible and effectivesurfactant/wetting agent

Water hardness orineffective chelating agents

Use of soft water or effectivechelating agents

2 Tendering or damage orloss in strength

1. Presence of air in themachine, leading to theformation of oxycellulose

2. Contamination of iron

1a. Exclusion of air1b. Use of mild reducing agent2a. Water purification2b. Use of appropriatecomplexing agent

BLEACHINGSr. No. Defects Causes Remedies

1. Uneven whiteness 1. Use of inappropriatesurfactants2. Water hardness3. Irregular chemical feeding4. Condensation or water marks5. Foaming in the bath6. Inappropriate use ofdefoamer

1. Appropriate/ compatiblesurfactants2. Soft water or use ofsequestering agents3. Optimum chemical feeding4. Optimum steaming conditions5. Appropriate use of defoamer6. Appropriate use of defoamer

2 Resist marks 1. Deposits of insoluble salts ofsurfactants2. Redeposition of impurities

1. Use of soft water orappropriate chelating agents2a. Careful selection ofscouring auxiliaries2b. Thorough washing afterscouring

BLEACHINGSr. No. Defects Causes Remedies

3. Harsh handle 1. Silicate deposits 1a. Use of organic stabilisers1b. Optimum control of pH(low pH reduces silicatesolubility)1c. Thorough washing afterbleaching

4. Fibre degradation ORReduction in fibrestrength

1. Metal contaminants 1a. Treatment of water toremove metal contaminants1b. Use of appropriatecomplexing agents

Sr. No.

Defects Causes Remedies

5. Low degree of whiteness(Bleaching fabric by pad-Steam)

1.Residual sodium acetate afterNeutralization2.Too low bleaching pH3.. short steaming time4. low steamingtemperature

1.Thorough rinsing afterNeutralization

2. Ph 10-113. Steaming 60-90min4. Steaming at 90-95◦ CCheck no leakage of steam

MERCERIZATIONSr. No. Defects Causes Remedies

1. Low increase in lustre

1.Low concentration of Caustic2. Insufficient fabric stretchingwhile on the frame3. Dwell time

1.Caustic concentration must be 52◦ Tw or 26 Be2. Use of tensioner device3. dwell time should be 60 sec

2. Poor shrinkagecontrol

1. Insufficient fabric stretchingwhile on the frame2. Too much caustic on the fabricas it comes off the frame

1. Optimum fabric stretchingwhile on the frame2. Removal of excess causticfrom the fabric before it comesoff the frame

DYEINGSr. No.

Defects Causes Remedies

1. 1. Poor Washing Fastness in Direct Dyeing

1. Dye substantivity, too high

2. Inherent low fastnessproperties of the dyes

1a. Treatment with Copper salts Copper sulphate 0.5-2% owf, Acetic acid 0.5% temp- 80◦C time 30-45min

1b. Treatment with chromium compoundPotassium dichromate 2-3% owfAcetic acid 1-2% owf Temp- boil , time -30 min

2. Use of cationic dye fixing agents orother fastness improving aftertreatment

PROBLEMS IN REACTIVE Sr .no. defects causes Remedies

1.Shade change/inconsistent shade

Shade change/inconsistent shade

1. Residual peroxide, alkalinity or other contaminants in the substrate2. Water hardness3. Contamination of dyebath withcalcium, magnesium, chlorine orheavy metals4. Improper use of dyebathassistants, e.g. surfactants,sequestrants, fixatives, lubricatingagents

1. Substrate free fromcontamination before dyeing2. Use of soft water or appropriatesequestrants3. Use of appropriate sequestrants4. Use of compatible dyebathassistants

2. Poor colour yield Poor colour yield 1. Poor pre-treatment2. Residual peroxide in thesubstrate3. Dye hydrolysis (only in caseof reactive dyes)

1. Good pre-treatment2. No residual peroxide in thesubstrate3a. Careful storage of dyes3b. Use of freshly prepared dyesolution

PROBLEM IN VAT DYEINGdefects causes Remedies

Poor levelling/unevendyeing

1. Low dye diffusion2. High dye affinity3. Dyes of poor migration4. Over reduction of the dye

.5 Low liquor flow rate6. Poor rinsing beforeoxidation7. Uneven washing/soapingafter-treatments.

1. Use of dyes of good diffusion2. Use of dyes of optimumaffinity3. Use of dyes of goodmigration4. Use of sodium nitrite to avoid over reduction of the dye

5. Optimum liquor flow rate6. Thorough rinsing beforeoxidation7. Thorough and uniformwashing/soaping after treatments.

Premature oxidation 1. Presence of air inside theMachine.2. Insufficient amount of sodiumdithionite and/or alkali

1. Prevention of air inside theMachine.2. Optimum amount of sodiumdithionite and/or alkali

cause reason remedie

Oxidation patch in vat dyeing

Improper oxidation - Sodium bicarbonate rinsing after after dyeing & prior to oxidation

Poor rubbing fastness 1. Dyes of poor rubbing fastness2. Catalytic damage of thematerial3. Presence of polyvalent ions4. Too high moisture in the testmaterial5. Improper use of finishing agent

1. Use dyes of good rubbingfastness2. No catalytic damage of thematerial3. Use of appropriate complexingagents4. Proper conditioning of the testmaterial5. Proper use of finishing agents

Problem Cause remedie

Shade change/inconsistent shade

1. Residual peroxide, alkalinityor other contaminants in thesubstrate2. Water hardness3. Contamination of dyebath with calcium, magnesium, chlorine or heavy metals4. Improper use of dyebath assistants, e.g. surfactants,sequestrants, fixatives, lubricating agents

1. Substrate free fromcontamination before dyeing2. Use of soft water orappropriate sequestrants3. Use of appropriatesequestrants4. Use of compatible dyebath assistants

Other Dyeing Problem

Problem Cause remedieSpecky dyeing. Too much foaming during

padding.

water drop on fabric before or after padding.

Add defoamer if required depending on class of dyestuff.

take preventive measures.

maintain the temp. speed & time .

Patchy dyeing. Insufficient dip in padding trough

Selection of proper padding mangle.

Centre to selvedge variation. Uneven wearing out of rolls of padding mangle.

Temp.gradient from centre to side of steaming chamber

Check the uniform expression of padding mangle.

Ensure uniform temp.across width of steamer.

Tailing effect. Too large size of padding trough. Use narrow & deep trough of smaller capacity.

Patchy DyeingShade Variation Shade Bar

Problem in Jigger Dyeing

defects causes Remedies

Dark or light selvedge . Non-uniform batching on jigger .

Proper batching on jigger.

Streakiness. Improper function of tensioning device in jigger lead to too high tension to wet state.

Ensure proper functioning of tension rollers on jigger.

Face to face variation. Too high batching tension on jigger.

Ensure correct batching on jigger.

Problems in Jet & Winch DyeingSr .no.

defects causes Remedies

01Crow –feet mark (crush mark).

Improper jet diameter . Use suitable jet depending on fabric quality.

02 Oil stains . Use wrong type defoamer which are break in rapid jet dyeing cause staining problem.

Use self emulsifying type silicone defoamer.

Crush marks Oil Stains

Problems in Continuous Dyeingdefects Causes Remedies

Specky dyeing. Too much foaming during padding.

water drop on fabric before or after padding.

Add defoamer if required depending on class of dyestuff.

take preventive measures.

maintain the temp. speed & time .

Choke feeding lines. Inferior dye dispersion Improper selection of dyestuff.

Centre to selvedge variation. Uneven wearing out of rolls of padding mangle.

Check the uniform expression of padding mangle.

Tailing effect. Too large size of padding trough. Use narrow & deep trough of smaller capacity.

Use hydraulic controlled rollers Colour dosing system PLC

Dye stuff stain Due to improper handeling improper mixing of dyes

•Ensure proper housekeepingProper mixing of dyes

Dye Stain White Spots

PRINTING

Defect cause by Hanging Thread

Problem Cause remedies

A break in Pattern of Printed fabric caused by Hanging Thread

Loose thread not treammed well before Printing

Non mendable

MISPRINT

Problem Main Cause Remedies:

MISPRINT

-Design not set properly

-unequal pressure

-Screen Design not Properly Engraved

-cloth feed with uneven tension

-Check Proper Feeding of cloth & Speed of m/c

-Ensure proper engraving of Design

TINTING

Problem  Cause  Remedies

Tinting

-Uneven Printing roller & doctor blade pressure

-Printing Paste level not maintained

-- defective doctor blade

- Printing table not proper

-Check viscosity of Printing Paste

-Check doctor blade

-Check Screen

BLURERD PATCH

-

Problem Cause Remedies

Blurred patch Uncleaned Doctor blade & printing roller

-Doctor blade not properly aligned

cleaned Doctor blade & printing roller

-Doctor blade properly aligned

WATER MARK

Problem Cause remedies

Water maks-Contamination with water prior to tinting on padding mangle-Surface pressure of one layer over another

-Ensure proper cleaning of padding mangle-- ensure optimum pressure

MISFITS

Problem cause Remedies

Misfits

-Printing screen Not adjusted properly-Improper feed of fabric-Faulty engraving

-Proper adjustment of screen-- ensure proper feed of fabric use guiders, feed rollers-Ensure proper Engraving acc. To pattern

FLUSHING

Problem Cause remedies

Flushing

-Printed area bleed into unprinted Portion-Removal of unfixed print

Do curing at reqired temperature

SPOTTING

Problem Cause remedies

Spotting-Unclean Screen roller

-Spots due to handling

-Poor uptake of print paste

-Cleaning of screen

-Avoid marks in steaming

-- ensure proper squeegee pressure

PRINT COLOUR VARIATION

Problem Cause  Remedies

Colour variation

-Uneven squeegee pressure

- Check even appliation of pressure through out application of print paste.

BLEEDING

Problem Cause Remedies

Bleeding-Too low viscosity of color paste-Too high dyestuff concentration

Ensure proper viscosity of Print paste - Ensure optimum concentration of dyestuff taken

STAINING DURING STEAMINGProblem Main cause  Remedy:

Staining during steaming

-Poorly washed printing Table

-Irregular Steam & temperature

Ensure Optimum Temperature while Steaming for reactive 102-105ºC

SLIGHT TOUCHING

Problem Main Cause Remedies

SLIGHT TOUCHING -Uneven Squeegee Pressure

-A squeegee with improper Hardness

-Improper viscosity of paste

-Improper use of thickener

-Optimum squeegee pressure

-- check squeegee before use

-Ensure viscosity of paste

-Proper use of thickner

DOUBLE PRINTING

Problem Main Cause Remedy

Double printing

-Disfigured design-Poor engraving-Poor cloth adhesion

Ensure Proper engraving

PRESSING PASTE BY FRAMEProblem Cause Remedies

Pressing paste-Poor belt drive and frame installation

-Frame mark in printed area

-Proper frame installation over fabric

FINISHING

STARTING MARKSProblem Cause Remedies

Staring marks 1. Sudden start, stopped of machine

2. Squeezing roll not properly clean

3. At start fabric pass throgh finishing chemical & not squeeze properly

1. Avoid sudden start and stoppage

2.Squeezig roller clean 3. Ensure proper squeezing

action

BOWINGProblem Cause Remedies

Bowing 1. Uneven tension during processing

2. Guiders not present

1. Maintain even tension

Use of Weft straightner

2. Use of guiders

PILLINGProblem Cause  Remedies

Pilling

1. Broken filament

2. Low twist

1. Shearing , singeing

2. Ensure optimum twit

PIN HOLESProblem Cause Remedies

Pin holes 1. Stenter pin 1. Go for clip

for holding fabric

Finishing (Stenter)Sr .no. defects Causes Remedies

01 Clips cuts and escape .

Inadequate grey width or reed space

Mechanical defect in clip bar & chain rails of the stenter.

Use provide adequate grey width & reed space with shrinkage expected.

Ensure proper maintenance of clips & chain rails of stenter.

02Yellow stains . Overheating & curing of the

finished especially when acid liberating are used in finish .

Optimum drying & curing condtion w.r.t time ,temp.

03Oil dropping & carbon soot .

Condensation of duct & water , oil particles

Ensure proper cleaning of stenter exhaust.

04 Uneven heat setting.

Variation in parameter Maintain parameter.

Calendering (Finishing)

Sr .no.

defects causes Remedies

01 creases & cut . non-alignment of guide rolls on calendering m/c giving rise to crease formation.Improper stitching of cloth.

Proper selvedge to selvedge stitching of material & proper feeding over well aligned guide rolls .

02 Dent mark & stains .

Dents in the calendering bow

Filling of dent.& proper brushing of the bowl .

Sanforiser (Finishing)

Sr .no. defects causes Remedies

01 Rubber blanket marks .

Dent or uneven surface of the rubber blanket .

Ensure proper and even grinding of rubber blanket .

REFRENCES• Towards zero Defect Amubhai patel

• www.textilelerner.com

• Major fabric defects during chemical processing • Quality and Process control S.M. Doshi & HA Shah • Chemical technology of fibrous materials - F. Sadov

• Technology of Dyeing – V. A. Shenai

• www.kyungin.co.kr/eng/sup/page1.htm#list1

• www.textileinfo.com

• www.alleycatscratch.com

• Critical Solutions In The Dyeing Of Cotton Textile Materials R. Shamey and T. Hussein

• Reduction of values in textile industry,(Bombay textile research ass.nov.14 1983) p-23-38.

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