Measures of Central Tendency: Mean, Median and Mode
Knit Dyeing Faults
1.
2. Prepared By :
Prepared By : Mazadul Hasan sheshir
ID: 2010000400008
13th Batch
Wet Processing Technology
Email: mazadulhasan@yahoo.com
Southeast University
Southeast University
Department Of Textile Engineering
I/A 251,252 Tejgaon Dhaka Bangladesh
3.
4. Oil and grease stains
Causes:
1. Inferior quality of oil used in Knitting
2. Excess oiling during knitting
3. Inferior quality of detergent used in pretreatment
4. Poor emulsification in case of excessive oil in
fabric
5. Improper washing
6. Not maintaining the critical temperature in
respect of emulsification
Remedies:
Emulsifiers are used to remove oil and grease
stains.
5. Rope Marks
Causes:
When scouring and bleaching the cloth in rope form under high pressure during
mangling, folds develop longitudinally.
Remedies:
In order to remove the folds, cloth is stentered and in case of severe folds it is
mercerized.
6. Poor Scouring
Causes:
When chemical, temperature,PH, time are not properly maintain then this fault is
form.
Remedies:
Properly control chemical, temperature, PH, time.
7.
8. Uneven Dyeing
Causes:
1. Uneven pretreatment (uneven scouring
& bleaching).
2. Improper color dosing.
3. Using dyes of high fixation property.
4. Uneven heat-setting in case of synthetic
fibers.
5. Lack of control on dyeing m/c
Remedies:
1. By ensuring even pretreatment.
2. By ensuring even heat-setting in case of
synthetic fibers.
3. Proper dosing of dyes and chemicals.
4. Proper controlling of dyeing m/c
9. Dye Stains
Causes:
•Dark selvedges are caused by non-uniform winding of cloth during dyeing on
jiggers. Bronzing effect also appears during dyeing in open jiggers with vat and
sulfur dyes.
Remedies:
•In case of vat and fast colors cloth should be stripped of color and re-dyed.
Boiling leveling bath should be used for direct dyed cloth. Leveling agents should
also be added.
11. Shade Variation
Causes:
It refers to color that exactly doesn’t match the standard of the prepared sample.
Remedies:
This may be due to faulty dye foundation or application or may be due to
variation in dye lot.
12. Hole (Dyeing)
Causes:
Due to problematic nozzle in dyeing m/c some holes may produce in fabric during
dyeing.
Remedies:
Nozzles must be cleaned time to time & maintenance should be done properly.
13. Barre Effect
Causes:
Basic difference in the polyester component particularly when using textured
filament weft.
Remedies:
Take appropriate preventive measure to avoid mix up of weft.
15. Color Bleeding
Causes:
•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.
Remedies:
•This problem can be minimizing by correct dyes and chemical selection.
16. Resist Spots
These show as areas where the dyestuff has not taken to the fabric
Condensation drips from roof
Marks or contamination on padder bowls
Fabric wet before dyeing
Undissolved chemicals
Poor preparation
Poor preparation
17.
18. Moire Effect (Stenter/ Compactor)
Causes:
Too high tension during batching and inadequate heat setting.
Remedies:
Proper tension during bathing & poor heat setting of fabric prior to dyeing.
19. Crease Marks (Hydro extractor)
Causes :
•Damp fabric moving at high speed in twisted form, in the Hydro extractor
(Centrifuge)
Remedies:
•Use anti Crease, during the Scouring & the Dyeing process
•(The use of anti-Crease, swells the Cellulose & prevents the formation of Crease
marks)
•Spread the fabric in loose & open form & not in the rope form, in the Hydro
Extractor.
20. Pin Marks ( Stenter )
Poorly adjusted stenter pin
21. Skewing (Compacting/ Stenter)
Fabric Wales appear in the diagonal direction, to the edges of the fabric, instead of
being parallel.
Causes :
•Improper feeding of the fabric, while Calendaring & Compacting.
Remedies:
•Keep a slit line on one side of the tubular fabric.
•Use the slit line, as a reference line, to keep the grain lines straight, while feeding
the fabric slowly, on the Calendar, or the Compactor machines.
22. Surface Hairiness & Piling(Tumble Dryer)
Causes :
•Abrasion due to the contact with rough surfaces
•Excessive surface hairiness caused, due to the abrasive tumbling action(Fabric
friction in the Tumble Dryer)
•Rough Dyeing process & abrasive machine surfaces (Soft Flow Machine tubes,
Tumble Dryer drum etc.)
•Reprocessing of the fabric is, also a major cause of piling.
Remedies:
•Avoid using the Tumble Dryer.
•(Control shrinkage by maximum fabric relaxation & over feed in the processing)
•Regularly inspect the fabric contact points on all the machines, for any rough &
sharp surfaces.
23. Lustre (Compacting)
Causes :
•Physical change in fiber due to local pressure and high temperature on material
•Excessive setting
Remedies:
•Avoid prolonged contact of stationary material with the hot machine
•Select suitable setting temperature
24. Spirality (Washing)
Spirality appears in the form of a twisted garment, after washing. The seams on
both the sides of the garment displace, from their position & appear on the front
& back of the garment.
25. Bowing ( Compacting/ Stenter )
Bowing appears as, rows
of courses or yarn dyed
stripes, forming a bow
shape, along the fabric
width.
Causes :
•Uneven distribution of tensions, across the fabric width while, dyeing or finishing
the fabric.
Remedies:
•Bowing can be corrected, by reprocessing the fabric, by feeding it from the
opposite end.
•A special machine (MAHLO) is also available for, correcting the bowing in the
knitted fabrics.
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