Knit dyeing faults and it’s remedies

 To know about the different types of wet processing faults. To know about the causes of different types of wet processing faults.. Description of wet processing faults has been found

Welcome to The Presentation

ON Knit Dyeing Faults and It’s Remedies

Submitted To

Rajib Saha Assistant Professor Department of Textile Engineering

ID: 2010000400008

Batch: 13th Batch (Session 2009-2013)

Department: Wet Processing Technology

 To know about the different types of wet processing faults.

 To know about the causes of different types of wet processing faults.

 To know about the remedies of different types of wet processing faults.

 To know about the pre-treatment process of textile goods.

 To know about the wet process of textile goods.

 To know about the finishing process of textile goods.

 To know about the different types of wet processing machineries.

 To know about the job sequence of wet processing industry.

Flow Chart of Knit Dyeing

in Knit Dyeing Processing

Description of wet processing faults has been found in knit dyeing:

Incomplete Scouring

Causes Remedy

 Too Low concentration of scouring chemical

 Too Low scouring temperature and time

 Ineffective surfactant / wetting agent

 Optimum concentration of scouring chemical

 Optimum scouring temperature and

 Time

 Effective surfactant / wetting

agent.

Low degree of whiteness

 In adequate concentration of H2O2

 Too low bleaching pH

 Too low bleaching time and temperature

 Optimum concentration of H2O2

 Optimum bleaching pH

 Optimum time and temperature

Faults Name Faults Sample

Effect of H2O2 residues

Causes Remedy

 H2O2 residues remove not properly

 H2O2 killer agent dosing not properly

 Not properly H2O2 killer runtime

 Running in alkaline condition

 H2O2 residues remove properly

 H2O2 killer agent dosing properly

 Properly H2O2 killer runtime

 H2O2 killer agent runtime must in acidic condition

Effect of Hairiness

Causes Remedy

 Not properly enzyme dosing

 High temperature enzyme Runtime

 pH not properly controlled

 Short runtime of enzyme wash

 When spoil of enzyme activity

 Required amount of enzyme dosing

 Temperature control properly

 pH controlled must be 4.5- 4.7

 Full time of enzyme run

 Properly enzyme stored in below 25tem

Faults Name Faults Sample

 Variation in drawing ratio in spinning

 Temperature variation during fixation process

 Exactly size of filling yarn

 Properly tension of yarn

 Proper thermo fixation process

 Selecting dyes and leveling agent which are not affected by the temperature variations

Shade bar

Causes Remedy

 It may be caused by a change of filling bobbin in the

loom or a loom stop and start up

 It is a horizontal band of a different hue running across the

fabric.

 Properly change of bobbin

Faults Name Faults Sample

Uneven dyeing

Causes Remedy

 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

 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

Line mark

Causes Remedy

 Long time store in the floor

 Dyeing process not properly

 Extra tension on the fabric

 Properly stored in the after dyeing

 Exactly dyeing process control

 Tension less fabric run in the dye bath

Faults Name Faults Sample

Batch to Batch Shade variation

Causes Remedy

 Fluctuation of Temperature

 Improper dosing time of dyes and chemicals

 Batch to batch weight variation of dyes and

chemicals

 Dyes lot variation

 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

Dye spot

Causes Remedy

 Improper Dissolving of dye particle in bath

 Improper Dissolving of caustic soda particle in bath

 By proper dissolving of dyes and chemicals

 By passing the dissolved dyestuff through a fine stainless steel mesh strainer, so that the large un-dissolved particles are removed

Causes Remedy

 Poor opening of the fabric rope

 Shock cooling of synthetic material

 If pump pressure and reel speed is not equal

 Due to high speed m/c running

 Maintaining proper reel speed and pumps speed

 Lower rate rising and cooling the temperature

 Reducing the m/c load

 Higher liquor ratio

Crease mark

Roll to roll variation or

meter to meter variation

Causes Remedy

 Poor migration property of dyes

 Improper dyes solubility

 Hardness of water

 Faulty m/c speed, etc

 Use standard dyes and chemicals

 Proper m/c speed

 Use of soft water

Faults Name Faults Sample

Thick –thin yarn

Causes Remedy

 If thick/thin yarn is used for making a fabric

 Used of immature fiber

 Used of short staple length of fiber

 After dyeing this type of problem cannot be removed but can be avoided by not mixing the thick/thin yarn in a single fabric

Off shade

Causes Remedy

 It refers to color that does not exactly

match the standard or the prepared

sample

 This may be due to faulty dyed

foundation or application or may be due

to variation in dye lot

 Properly select of dye

 Correctly fabric lot selection

Faults Name Faults Sample

Insufficient hydrophilic

Causes Remedy

 Insufficient removal of grease, wax and sizing film which

gives hydrophobic characteristics to the fabric When a

fabric with un uniform hydrophilic is dyed, areas with

different lower / hydrophilic results in a lighter shade are

obtained due to the lack of absorption of the dye liquor

 To avoid this a thorough pre-treatment is a must,

 Wetting agent can be used in dyeing liquor

Bowing

 Woven filling yarns lie in an arc across fabric

width; in knits the course lines lay an arc across

width of goods

 Establish standards of acceptance Critical on

stripes or patterns not as critical on solid color

fabrics

 Uniform sewing is required

 Equal width fabric is required

 Proper tension fabric passes in compactor

Faults Name Faults Sample

Compacting crease

 Excessive apply on Teflon pressure

 Less tension roller

 Uneven temperature of two cylinders

 Minimum required of Teflon pressure

 Exact setting of tension roller

 Exact setting of temperature in cylinder

Faults Name Faults Sample

Poor washing fastness

Causes Remedy

 Inadequate washing of hydrolyzed dye

 Inadequate removal of loosely retained dye

 Inherent low fastness properties of the dye

 Optimum washing off

 Use of cationic fixing agent or other fastness improving after treatment

Oil & Grease Spot

Causes Remedy

 During dyeing and finishing process sometimes oil and grease

may fall on fabric which may cause oil and grease spot on the

dyed fabric

 Due to careless transport of dyed or finished fabric

 Must be careful about oil and grease during dyeing and finishing process

 Must be careful about the transportation of dyed or finished fabric

 With immediate application of spot –lifter

Faults Name Faults Sample

Pilling effect

Causes Remedy

 In producing a yarn fibers tightly twisting produce a serviceable yarn

When short stable fibers are mixed into the yarn the result is a yarn that

will not 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.

Two months industrial training at Alim knit tex (Mondol Group) Ltd, Metro Knit and Dying Mills Ltd, Square Knit Fabrics Ltd were a part of B.Sc in Textile Engineering course During the training period the whole 60 days were segmented and scheduled to a systematic routine There was different faults operation in textile wet processing.

It should be mentioned that Alim knit tex (Mondol Group) Ltd, Metro Knit and Dying Mills Ltd, Square Knit Fabrics Ltd are 100% export oriented knit dyeing industry To produce a quality product above all export quality it could be desirable that the process should be high standard.

Here we have some limitations in our training period, and two months are not enough time to complete the knowledge about the textile terms.