SOUTHEAST UNIVERSITY DEPARTMENT OF TEXTILE ENGINEERINGKNIT DYEING FAULTS & REMEDIES

SOUTHEAST UNIVERSITY DEPARTMENT OF TEXTILE ENGINEERING

KNIT DYEING FAULTS & REMEDIES

Southeast University Department Of Textile Engineering

I/A 251,252 Tejgaon Dhaka Bangladesh

Prepared By : Mazadul Hasan sheshirID: 201000040000813th Batch Wet Processing Technology Email: mazadulhasan@yahoo.comSoutheast University

WHY DYEING FAULTS OCCURS:

Why Dyeing Faults occurs:

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.

EXAMPLE OF DYEING FAULTS

Uneven dyeing. Running shade. Batch to batch shade variation. Patchy dyeing effect. Roll to roll variation or Meter to meter

variation. Crease / Wrinkle mark. Dye spot. Softener mark. Fabric hole.

Uneven dyeing.

Causes:• Uneven pretreatment (uneven scouring & bleaching).• Improper color dosing.

Remedy:• By ensuring even pretreatment.• Proper dosing of dyes and chemicals.

Batch to Batch Shade variation:Causes:• Fluctuation of Temperature.• Improper dosing time of dyes & chemicals.

Remedies:• Use standard dyes and chemicals.• Maintain the same liquor ratio.

Patchy dyeing effect.Causes:• Faulty injection of alkali.• Due to improper salt addition.

Remedy:• Proper dosing of dyes and chemicals.• Heat should be same throughout the dye liquor.

Roll to roll variation or Meter to Meter variation:

Causes:• Poor migration property of dyes.• Improper dyes solubility

Remedies:• Use standard dyes and chemicals.• Proper m/c speed.

Crease mark:

Causes:• If pump pressure & reel speed is not equal.• Poor opening of the fabric rope.

Remedy:• Maintaining proper reel sped & pump speed.• Lower rate rising and cooling the temperature.

Dye spot:Causes:• Improper Dissolving of dye particle in bath.• Improper Dissolving of caustic soda particle in bath.

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.

Crease/Wrinkle mark:Causes:• Poor opening of the fabric rope.• Shock cooling of synthetic material.Remedies:• Maintaining proper reel speed & pump speed.• Lower rate rising and cooling the temperature.

Softener Mark:Causes:• Improper mixing of the Softener.• Improper running time of the fabric during application of softener.Remedies:• Maintaining proper reel sped & pump speed.• Proper Mixing of the softener before addition.

Fabric hole.causes:• More acid of knit fabric in the dyeing section.• Temperature highly.

Remedy:• Use standard Acid.• Proper dosing of Acid.

Some other faults 1. Long mark 8. Fly we 2. Loop mark 9. Brush problem 3. Dhappa spot 10.Uneven even hairiness 4. Yellow spot 11. Water spot 5. Iron spot 12. soda spot 6. Out color 13. Lycra out 7. Enzyme dust 14. Patta fault

Finishing faults in the Textile: Ballooning shape. Radish shade. Squeezer mark. Dia mark. Dirty spot. Compaction /Press mark. Compacting hole. Crease mark. Calendaring crease. Oil Spot. Improper shrinkage. Bowing: Crease Streak:

Fabric Fault Inspection:The inspection of fabric is a procedure by which the

defects of fabric are identified and fabric is classified according to degree or intensity of defects. The fabric inspection is done for both grey and finished fabric.

Fabric inspection :Two ways of grey fabric inspection used to done by- a) Auto turning fabric inspection m/c. b) Varivide colour assessment cabinet –2 D-65, TL-84, TL-83,

Florescent, UV.

Conclusion Fabric and Garments defect are the most important in

garments factory. It is very harmful for garments industries. Considering the objective of the work, a systematic investigation on ‘Knit dyeing Faults and Remedies’ were performed in the training period. All the activities had been done maintaining in sequence of the machinery of the production. There are many common defects which are continually detected in the fabrics which are described in Methodology. The purpose of our project is identifying the faults of fabric and garments. We were identifying the fabric and garments faults very closely and very carefully.