Survey on dyeing faults

Improper setting of yarn packages in the machine b.. Improper setting of yarn packages in the machine b.. Foreign particles present on fabric before dyeing b.. Crease MarkCauses: a.Lack

Southeast University

KNIT DYEING

YARN DYEING WOVEN

DYEING

Prepared By : Mazadul Hasan sheshir ID: 2010000400008

13 th Batch (session 2009-2013) Department : Wet Processing Technology Email: mazadulhasan@yahoo.com

Blog : www Textilelab.blogspot.com (visit)

Southeast University

Department Of Textile Engineering

I/A 251,252 Tejgaon Dhaka Bangladesh

Prepared By :

Faults in Dyeing Sector

Yarn Dyeing Faults

1 Package Unlevel

Causes:

a Tension variation while soft winding of the

package

b Lot mixing of yarns in the same package

c Different counts of yarns in the same

package

d Pressure variation in the machine vessel

e Improper pretreatment of the yarn

f Improper quality of the dyes and chemicals

g Improper acid treatment after scouring and

bleaching

2 Package to Package shade variation

Causes:

a Improper setting of yarn packages in the machine

b Lot mixing of the packages

c Count variation of packages

Causes:

a Improper setting of yarn packages in the machine

b Lot mixing of the packages

c Count variation of packages

e

Unlevel

3 Color Spot

Causes:

a Floating of dye particles in the air

b Improper per-oxide killing

5 Ring Mark

Causes:

a Improper drying of the packages

b Improper peroxide killing

4 Dirt Mark

Causes:

a Dirty handling of the packages

b Presence of dust in the air

Figure: Dirt mark

Woven Dyeing Faults

a Foreign particles present on fabric before dyeing

b Foreign particles present in the solution

c Hairiness present in fabric from brushing

1 White Spot

2 Color Spot

Causes:

1 Dyes & chemicals factors:

a Poor Dispersion or Solubility Properties

b Unstable chemicals

c Silicones in the dye bath

d Alkali residues in the goods

e Presence of iron

2 Improper Washing

3 Operator negligence

1 2 3 4 5 6 7 8 9 10 11 12

3 Crease Mark

Causes:

a.Lack of balance in construction of the fabric

b.Pressure of padder roller

c.Direct Heating or Shock cooling

4 Long Stripe

Causes:

a Winding of yarn in padder roller

b Improper pressure during brushing

1 2 3 4 5 6 7 8 9 10 11 12

d Low solubility of dyes & chemicals

e Negligence of operators to solubilize dyes and

chemicals

7 Listing Effect

Causes:

a Improper padder pressure in different zones of padder roller (left, middle & right zone)

b Worn out squeeze roller

8 Dirt Spot 9 Oil spot

Cause:

Oil dropped on the fabric

1 2 3 4 5 6 7 8 9 10 11 12

Causes:

Presence of Dirt in the air

Dirty handling of the fabric

1 Insect present in any bath

(i.e dye bath, chemical bath, washing bath)

2 Falling of insects on the fabric during dyeing

10 Water Mark

Cause:

Water is dropped on the fabric after final drying

1 Uneven Dyeing

2 Shade variation

i) Roll to roll shade variation

ii) Batch to batch shade variation

iii) Continuous shade variation in a roll

(Running shade/Tailing effect/Ending

effect) iv) Side center side shade

v) Side to side shade

1 Uneven Dyeing

Causes:

i) If uneven pretreatment is done, absorbency and whiteness of fabric will be different at different places and consequently uneven dyeing will occurred

ii) Very rapid addition of dyes and chemicals

iii) Lack of controlling dyeing machine like-

- Machine over-loading

- Running at lower nozzle pressure

- High bath draining temperature

- Improper cycle time

- Improper length of rope

i) Different batches are pretreated in different machines

ii) Fabric of different batches has different dye affinity

iii) Liquor ratio, cycle time, dye lot, chemicals, dyeing procedure, temperature are different for each batch

iv) Low quality water especially PH, hardness and sodium carbonate content

2.3 Running shade

- More cycle time, more time fabric will be in folded condition increase tendency to crease mark

formation

- Faulty plaiting device

- Variation of heating & cooling rate

- Improper fabric movement

- For 100% cotton, if GSM>180, unbalanced structure, presence of lycra, not properly heat set increase the tendency to crease mark formation

4 Dye Spot

Causes:

i.Operator negligence

ii.Dye bath hardness

iii.Improper Agitation of dyestuff

iv.Dye molecule deposition on the fabric

1.Soaping start before wash

2.CaCO3 or MgCO3 in soaping bath

6 Hole

Causes:

1 Dye bath water hardness

2 Deposition of ferrous or ferric ion on the

fabric surface

3 Defective plaiting device of the machine

Properties of Dyes & Chemicals affect fastness.

c Hand feel problem

1 Yarn Manufacturing Technology