....DYEING , PRINTING AND

FINISHING DEFECTS AND REMEDIES….

The reasons like water, fiber sources & processing conditions is responsible for defects during wet processing. However, in order to overcome/ minimize the processing related problems it is essential to first understand the Symptoms (problems), Diagnose (ascertain the probable cause) & Cure (adopting remedial measure).

Some defects of various stages are disscussed below:

Causes Of Dyeing Defects

Due to Material:– Material having dead fibers or other defective fibers.

– Left over of Chemicals after scouring, bleaching etc.

– Material not properly singed, desized.

– Material not properly mercerized.

– Absorbency of the fabric not proper.

– Sticking of insoluble material on the fibers.

– Impurities are not removed properly.

– Uneven heat treatment.

Causes Of Dyeing Defects

Due to Water Quality:– More Hardness of water

– Water has metal ions such as iron.

– pH of water not proper

– Water having more chlorine

Due to Improper Dye Solution:– Improper weight ratio of colors, material and chemicals.

– Improper material to water ratio

– Improper filtering of concentrated colors.

Dyeing Defects

Bleeding

• It’s a loss of color when the dyed fabric is wetted or emerged in water.

• The water here, becomes colored and may cause discoloration of other fabrics.

• This is usually due to either improper dye selection or poor dye fastness.

• It is the rubbing off of the color.

• It may rub onto another fabric.

• This may be due to inadequate scoring subsequent to dyeing.

Crocking

Shade Bar

• It is a horizontal band of a different hue running across the fabric.

• It may be caused by a change of filling bobbin in the loom or a loom stop and start up

Hole in sulfur dyed fabric

• Caused due to tendering which

takes place because sulphur is

converted into sulphuric acid

after oxidation which is harmful

for the cellulosic fibers.

• This is a major defect. The defect

occurred after washing the garment.

Off Shade

• It refers to color that doesn't exactly match the standard or the prepared sample.

• This may be due to faulty dye foundation or application or may be due to variation in dye lot.

Uneven Dyeing

Batch to batch Shade Variation

Patchy Dyeing Effect

Roll to Roll Variation

Crease Mark

Printing Defects

Flushing/Wicking

• Caused due to Low viscosity of print paste.

• It occurs when the printed area

bleeds out into the unprinted

area. The result is a ‘haloing’ or

shadowing effect around the

outline of the pattern design.

Bleeding

• Caused due to Low viscosity of

print paste

• It is major defect as it happens

throughout the fabric unless

the viscosity is corrected.

Misfits

• A misfit is a print defect caused by improper alignment of the

screens. Also known as “out of registration, misfits leave

unprinted areas in the design.

• For example, a green leaf may overlap its black outline or

print over another color.

Banding

• Defect created by the print head’s movement over the substrate.

• Use of scanning print head, or a print head that moves back and forth

across the substrate in straight line placing drops of ink at precise

locations along the line.

• If the head is not properly aligned, or if the substrate advances

unevenly, the result is a slight horizontal “band” or line of unprinted

area.

Unwanted pigmentmarking on fabric

• Caused due to screen has holes

in it that should have been

covered. This could be because

of ageing of the screen and

eventual damage or just

improper exposure to light.

Crack or miss alignment in transfer printed fabric.

• Incomplete transfer of design

from paper to fabric on transfer

printing due to removal of

transfer of paper while the

fabric was still hot.

Finishing Defects

FABRIC FINISHING

• A series of processing operations applied to

gray fabrics to enhance their appearance and

hand, properties and possible applications.

• Play a fundamental role for the commercial

excellence of the results of textiles

FABRIC FINISHING

• The most simple form of finishing is the ironing or pressing on the fabric.

• In finishing , the fabric is subjected to mechanical and chemical treatment in which its quality and appearance are improved and its commercial value enhanced.

• Physical finishing techniques(dry finishing processes) or chemical finishing methods(wet finishing) are used.

FABRIC FINISHING

• Functional finish:

– Wearability, Hand, Mechanical resistance,

Easy care, Wettability, Washability,

Deformability, Anti bacterial, Anti fungal,

Soil-proof and Fire-proof ability

• Aesthetic finishes:

– Aesthetic looks

• Oily stains with dust adhered to

surface which makes the stains

more prominent and difficult to

remove, due to contact with oil

or grease covered exposed

machine parts, careless handling

could be another cause.

Unwanted marks on fabric.

• Caused due to

– chemical spillage on fabric.

– Localized excess bleaching.

– Localized excess enzyme wash.

• Can be result into weakening of

the fabric.

Decolorized patch on fabric

• Holes along selvage caused by pins holding fabric while it

processes through tenter frame.

• Major defect if pin holes extend into body of fabric far

enough to be visible in the finished product.

Pin Holes

• Results from uneven wetting out on sanforize.

• usually caused by defective spray heads.

• Fabric will appear wavy or puckering when spread on cutting

table.

• Difficult to detect during inspection on inspection machine

with fabric under roller tension.

Sanforize Pucker

Bowing

• Usually caused by finishing.

• Woven filling yarns lie in an arc across fabric width; in knits

the course lines lie an arc across width of goods.

• Establish standards of acceptance. Critical on stripes or

patterns; not as critical on solid color fabrics.

Pilling

• Pilling is a common fabric defect occurring on knitted and woven fabrics.

• In producing a yarn, long fibers tightly-twisted produce a serviceable yarn. When short stable fibers are mixed into the yarn the result is a yarn that will not hold together. The short staple fibers will separate from the yarn and curl up in a ball, forming what is referred to as a pill.

• Pilling is accentuated by the friction of normal wear, washing and routine dry cleaning.

Water Spots

• Usually caused by wet fabric being allowed to remain too long

before drying; color migrates leaving blotchy spots.

Selvage Torn

• Usually caused by excessive tension while processing through tenter frames.

Cuts or Nicks

• Caused by indifferent handling of scissors. snips ormechanical trimmers.

Soil

Caused by oil, grease or dirt. Often times originating from a dirty work area or machinery not properly cleaned