Faults in knit dyed fabric

Faults in Knit Dyed Fabric

Name : MAZADUL HASAN SHESHIRID: 2010000400008Batch: 13th Batch (Session 2009-2013)Department: Wet Processing Technology Email: mazadulhasan@yahoo.comBlog: www. Textilelab.blogspot.com Southeast UniversityDepartment of Textile Engineering

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Knitting faults

Yarn dust

Causes of faults: - Fly yarn/ foreign fiber

Remedies: - Proper air suction

Set-up

Causes of faults: - For badly needle break Yarn break

Remedies: - Remove bad needle Maintain proper tension

Loop mark

Causes of faults: - Defective needle Not properly needle

latch work

Remedies: - Change new needle By clean needle latch,

hook

Needle break

Causes of faults: - High yarn tension Bad setting of the yarn

feeders Old and worn out needle

set

Remedies: - Ensure uniform and right

yarn tension on the feeders

Keep the recommended gap between the yarn feeders and the needles

Periodically change complete set of needles

Oil spot

Causes of faults: - Due to contact with oil or

grease covered exposed m/c parts

Careless handling could be another cause

Remedies: - Use of strong knitting oil

which can be removed After every process, if

possible check filter and clean it

Thick place

Causes of faults: - Different yarn count Use unmatured fiber

Remedies: - Select matured fiber Check /indentify the

yarn thick/thin place

Mix yarn/Lot mix

Causes of faults: - Unawareness of

operator

Remedies: - Awareness in

production

Hole

Causes of faults: - Holes are the results of yarn

breakage Yarn tension too high Presence of knots in yarn If the yarn count is not

correct

Remedies: - Yarn strength must be

sufficient Maintain proper tension Knots should be given

properly Use proper count of yarn

Lycra out

Causes of faults: - Yarn tension too high Lycra guide roller block

or jam Needle not properly work

Remedies: - Maintain proper yarn

tension Ensure smooth running

of guide roller Change defective needle

Yarn contamination

Causes of faults: - Presence of dead fibers

and other foreign materials Presence of the foreign

materials, in the stable fiber mixing

Remedies: - Use rich fiber mixing for

the yarns Segregate the knitting m/c

with mosquito nets to prevent the fibers flying from neighboring

Miss yarn

Causes of faults: - Yarn break Positive feeder jam Excessive needle tension Weak yarn

Remedies: - Yarn strength must be

sufficient Smooth running of feeder Proper needle tension

Tara fault (Star)

Causes of faults: - For high r.p.m of m/c

cylinder One part dyeing

Remedies: - Maintain proper r.p.m of

m/c cylinder Range should be upto

23

Dyeing faults

Uneven dyeing

Causes of faults: - Inadequate scouring of the

grey fabric Correct pH value not

maintained Water hardness Improper neutralization Improper migration

Remedies: - Scour the grey fabric

thoroughly, to remove all the impurities from the fabric

Maintain the correct pH value Maintain water hardness Proper neutralization Proper migration

Uneven dyeing

Causes of faults: - Improper neutralization Improper dyes dosing Improper soda dosing Improper migration Improper leveling agents

Remedies: - Proper neutralization Proper dyes dosing Proper soda dosing Proper migration Proper leveling agents

Uneven dyeing

Causes of faults: - Dyeing m/c stoppage, due to

power failure or the fabric entanglement in the dyeing m/c

Correct pH value not maintained

Improper leveling agent Water hardness

Remedies: - Use a power back up for the

dyeing operation to be completed uninterrupted

Maintain correct pH value Use appropriate leveling agents Maintain water hardness

Dye spots

Causes of faults: - Colored spots due to

dye deposits on the m/c

Remedies: - Pay attention to

cleanness in the m/c

Pilling

Causes of faults: - Due to friction of fabric Poor yarn quality

Remedies: - Need good enzyme

treatment By using combed yarn

Uneven dyeing

Causes of faults: - Improper migration Improper neutralization Inadequate scouring of

the grey fabric

Remedies: - Scouring the grey fabric

thoroughly Proper migration Proper neutralization

Soda spot

Causes of faults: - Improper dosing of soda

Remedies: - Proper dosing of soda

Finishing fault of knit dyeing fabric

Uneven

Causes of faults: - Unstable dye dispersion Dispersing agent not

enough Wrong temperature

Remedies: - Select dyes with better

dispersion stability Proper temperature

maintained

Skew

Causes of faults: - Over width for this

fabric

Remedies: - By using weft

straightening device Maintain proper width

Slitting fault

Causes of faults: - It is causes due to

operator carelessness

Remedies: - Operators have to slit

fabric through slitting mark

Uneven brushing

Causes of faults: - Not proper soft Roller pins problem

Remedies: - Use softener Check pins

Crease mark

Causes of faults: - Improper motion of

padder Improper fabric

movement

Remedies: - Proper motion of padder Ensure smooth running

of fabric Use anti-creasing agents

Unwanted mark

Causes of faults: - Due to contact with oil

or grease covered exposed m/c parts

Careless handling could be another cause

Remedies: - Use of strong oil which

can be removed Proper handling should

be taken

Oil mark

Causes of faults: - Due to contact with oil

or grease covered exposed m/c parts

Careless handling could be another cause

Remedies: - Use of strong oil which

can be removed After every process, if

possible check filter and clean it

Silicon spot

Causes of faults: - Long time deposit of

solution Improper mixing of the

silicon

Remedies: - Proper mixing of the

silicon Use the right silicon Maintain the correct pH

value, before application

Silicon mark & Burn effect

Causes of faults: - Long time deposit of solution Improper mixing For over or high temperature

this burn effect is visible Twice stenter

Remedies: - Proper mixing Select suitable silicon Maintain correct temperature

Line mark

Causes of faults: - This mark are caused

due to the excessive pressure of the roller

Remedies: - Pressure of roller should

be maintained Take care of fabric

Burning effect

Causes of faults: - For wrong temperature Unawareness of

operator

Remedies: - Maintained proper

temperature By using experienced

manpower

Chemical spot

Causes of faults: - Improper mixing of

chemical Weak chemical Unawareness of operator

Remedies: - Proper mixing of chemical Use appropriate chemical By using experienced

manpower

Uneven brushing

Causes of faults: - Too much pressure of

the cylinder roller is the causes

Remedies: - Operator should take

care when fabric is running

Uniform motion R.P.M should maintained

Uneven brushing

Causes of faults: - Too much pressure of

the cylinder roller is the causes

Remedies: - Operator should take

care when fabric is running

Uniform motion R.P.M should maintained

Sewding fault

Causes of faults: - Wrong m/c set up Over speed /r.p.m Displace of pin

Remedies: - Installed proper m/c set

up Maintain correct

cylinder speed Check and proper

placement of pin

Unwanted mark

Causes of faults: - Due to contact with iron

rust from m/c parts If fabric wet long time Unclean roller or padder

Remedies: - Try to clean m/c parts Keep fabric dry Clean roller and padder