3. INTRODUCTION
Dyeing is a process of treating fabrics with dye
liquors which contains both dyestuffs and chemicals
and fixing the dyes in the fabric subsequently.
In discussing faults which can be attributed to dyer
and finisher, it is necessary first to have a general
conception of some of the major operations to
which goods are subjected after they are received by
the finisher of wet processing .
4. OBJECTIVES
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.
5. FLOW CHART OF KNIT DYEING
Grey Fabric
Stitching
Singeing
De-sizing
Scouring and
Bleaching
Dyeing
Finishing
Open Fabric
Slitting
Stanter
Compactor
Tube Fabric
Dewatering
Dryer
Compector
Inspection
Packing
Delivery
6.
7. Description of wet processing faults has been found in knit
dyeing:
Faults Name Faults Sample
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.
8. Faults Name Faults Sample
Low degree of whiteness
Causes Remedy
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.
9. 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.
10. Faults Name Faults Sample
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.
11. Faults Name Faults Sample
Barrie
Causes Remedy
It may be caused by variation in the
size of the filling yarn
By the differences in tension of
either the filling or warp yarn
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.
12. Faults Name Faults Sample
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.
13. 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.
14. Faults Name Faults Sample
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
15. 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.
16. Faults Name Faults Sample
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.
17. 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.
Faults Name Faults Sample
Crease mark
18. Faults Name Faults Sample
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.
19. 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.
20. Faults Name Faults Sample
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.
21. 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.
22. Faults Name Faults Sample
Bowing
Causes Remedy
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.
23. Faults Name Faults Sample
Compacting crease
Causes Remedy
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.
24. Faults Name Faults Sample
Water spot
Causes Remedy
Fixation with a few drop of water
on specific area of dyed fabric
Proper fixation
25. 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.
26. Faults Name Faults Sample
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.
27. Faults Name Faults Sample
Pilling effect
Causes Remedy
Pilling is a common fabric occurring on knitted
and woven fabrics.
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.
Exactly maintain of enzyme wash.
Evenly mixing of short staple fibers.
Properly twisted of yarn.
28. CONCLUSION
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.