Best Practices in Weaving
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Transcript of Best Practices in Weaving
Best Practices in Weaving
To meet the ever-growing demands of quality and quantity of the textile industry, the world
of weaving has witnessed tremendous technological advancement during the past three
decades. The innovations were not confined to final stage of fabric forming but also at various
stages of weaving and weaving preparatory. The fabric forming technology has taken a big
leap from handloom weaving of primitive years to power loom atomize weaving to today’s
high-speed shuttle less weaving technology. It is the result of persistent efforts put in by the
scientists and technologists over the years. These sophisticated weaving technologies are
considered as basic tool to ensure high productivity and quality in fabric. The mere existence
of sophisticated weaving technology alone will not ensure fulfillment of above goals and thus
it is needless to say to handle such sophisticated weaving technologies, also need best work
practices by the people handling these technologies, to ensure efficient weaving operations.
It will not be out of the place to discuss the process flow of weaving and then the best
practices to be followed at each stage of fabric manufacturing.
A systematic process flow diagram will help to understand weaving in a better way.
Yarn from Spinning
Winding
Direct Warping Sectional Warping
Warping
Drawing in / Knotting
Weaving
Sizing
Fabric Inspection
Yarn Dyeing
Best Practices in Yarn Go down
Weaving process converts yarn in to fabric therefore the yarn is considered as raw material
for weaving. Yarn is supplied to the weaving mill by Yarn supplier or spinning mill directly
in the form of cones, which is stored in Yarn Go down.
In Yarn go down following practices must be carried out for smooth functioning.
All cones should be packed in polythene bags before transported to next process.
Proper stacking of yarn, received from different suppliers to avoid lot to lot and
package to package variation for further process i.e. Dyeing and Weaving.
Provide protection to the yarn, against external damages like bad handling, sunlight
and rain.
Easy availability of yarn at one place for easy handling and to reduce machine down
time of further process.
Make proper record of yarn received from supplier, Issued against requirement and
received return from Winding, Warping, Dyeing and Weaving department.
Identify the trend of consumption of yarn separately for better inventory.
Control on yarn wastages.
Best Practices in Winding Process
Winding converts, yarns from smaller spinner’s bobbins to big cones in the form of soft and
hard. Spinner’s bobbin contains 60 – 80 Gms of yarn (3,000 – 5,000 mtrs) which are
converted in to larger yarn package known as cone
containing approx. 1.25 to 1.5 Kg of yarn
(1,00,000 -1,25,000 mtrs). Soft cones are used for
‘yarn dyeing purpose’ where as hard cones are
used as ‘weft for weaving’ and as ‘cones for direct
warping’. Soft cones after dyeing are further
converted in to as ‘big cones for dyed weft’ or ‘small cones (Length of cones depends up on
the fabric order length) for sectional warping’. Winding process also removes objectionable
yarn faults from yarn during winding.
In winding process following practices must be carried out for smooth functioning of further
process like warping and weaving.
At 6% moisture content cotton shows high strength
therefore it is very much essential to condition the
yarn before further process.
Yarn received from dyed yarn ware-house for warp
winding must have right information on it like
production order no., issued quantity, Count, Shade
no., Lot no. etc.
Before warp winding must check for package
condition, shade variation in packages, Bronziness
problem etc. to avoid fabric defects which are observed only after weaving.
Yarn must wound on clean empty cones specified for that particular count.
Inner layer (Bottom) of dyed package yarn must remove during winding to avoid yarn
dyeing defect in fabric like undyed & uneven dyeing. In normal practice for lighter
shade 10-15gms and for dark shade 20-25gms of yarn are removed from each dyed
packages.
Never mix different lots even it is same in
shade. Use of identification sticker will help.
Use of different size of dyed yarn packages is
advisable to avoid shade variation problem in
weft chambray fabric.
Always use Knotter for mending broken end.
Frequent checking of splicing quality and strength of knot for at least 10% of drums/
day will ensure better machine condition.
Frequent checks for yarn passage of each spindle, yarn tension, tension unit disc
position, and removal of fluff and wild yarn helps for better winding quality.
Preset all machine settings to remove all the objectionable faults and check frequently
to ensure zero deviation.
Winding
Ensure Good housekeeping and PEEP Management system. (Place for Everything and
Everything in Place)
Less attending time to start stopped drums, improves productivity.
Use of nose mask avoids inhaling of fly and fluff.
Best Practices in Warping Process
The initial stage in producing woven fabric is to convert yarn from cones to warp beams.
Warping provides even and parallel distribution of warp ends over the entire width of the
warping beam. Direct warping and Sectional warping are two types of warping and widely
used in industry. When several beams with same beam length are prepared and then all beams
are unwound on the weavers beam is called as direct warping. This type of warping is more
productive and commonly used for bulk production. Similarly when several sections are
wound in a sequence which is parallel to each other on a drum and then all sections are
unwound on the weavers beam is called as sectional warping. This type of warping is cost
effective for short and striped warp and fancy pattern fabric.
In warping following practices must carry out for smooth functioning in weaving.
Cleaning of machine at every creel
change will improve productivity
of warping machine.
Polishing of weavers beam flanges
to avoid scratches on it helps to
reduce warp brakes.
Even tension throughout the warp
sheet will ensure good quality of warping.
Broken ends should mend correctly i.e. first find out the missing ends in the drum by
reversing 2 to 3 turns and then mend it.
Never use two different yarn lots in same creel.
Ensure even creel tension or warping speed in between one set.
Direct Warping
For beam dyeing beam density should maintain at 360 to 400gms/ltr.
Creeling of cones must be done and
checked thoroughly as per as per the
pattern given in design sheet.
Do not use damaged cones, it will cause
frequent breakages of warp yarn and
minimize the productivity.
First pattern always starts from right side
of the creel.
Adjust the section width and section starting position for every section start-up to
avoid section mark in the fabric.
Use of seven leases and cross lease during each section winding improves working in
sizing and weaving.
Best Practices in Sizing Process
Strong, smooth and elastic yarn is the prime requirement of weaving process. To achieve
these properties without deteriorating the inherent quality of yarn a starch /polymeric film or
coating is applied on the warp yarn. During application of size it get penetrated in to the yarn
structure and enhances its breaking load capacity, softeners makes surface smoother and
binders binds protruding fibers of yarn resulting improvement in the warp yarn strength,
smoother yarn surface and reduction in hairiness of yarn.
In Sizing following practices must carry out for smooth functioning in weaving.
Frequent check and maintain
viscosity and RF value of the size
recipe.
Close monitoring on temperature of cylinders and size-box at every stage of sizing.
Close monitoring on machine parameters like squeezing pressures, dividing zone and
drag roll tension etc.
Sectional Warping
While inserting lease rods start the machine in slow speed and ensure comb assembly
is lowered while knots are passing.
Do the denting in the comb by using
cross lease, starting from the centre
of comb.
Apply the press roller after 20-25
mtrs, then run the machine at normal
speed i.e. 40 mtrs /min.
Maintain sheet opening angle equal
to lease rod dia. and stretch always maintain below 1%.
Ensure sized beam moisture content in between 5% – 6 % because less moisture in
sized yarn makes it brittle and more moisture makes it sticky.
Drain used size recipe from saw box and clean saw box properly, if light color set is
running after dark color set.
Don't reuse the old or used size recipe.
Don't allow un-dried portion to go inside the sized beam.
Don’t apply high stretch on warp sheet, will result in elongation loss of yarn and cause
high warp brakes in weaving.
Don’t size single count and double count together, double count will get loosen and
created crossing and migration in sizing and warp brake at weaving.
Use even warp tension across the width of the beam.
Best Practices in Drawing- in Process
After sizing, sized weaver beams are sent to drawing in department to draw each warp ends in
predetermined drawing sequence provided by the design department. Design sheet provides
information which is required for drawing in like Draft, Denting Plan and Warp Pattern. In
drawing in each ends are threaded through a drop pin, heald eye and the reed according to the
plan. After completion of drawing in process drawn set goes to weaving and gaited on loom.
For better performance in weaving and quick startup of loom a drawn set must have almost
zero broken ends and crossing ends. Broken ends and crossing ends need more time to mend
and correct it thus in most of the case it is the only reason for higher beam gaiting time
resulting less productivity of loom.
In Drawing- in following practices must carry out for
smooth functioning in weaving.
Warp sheet should properly brush and combed
at the preparation stage, to ensure
parallelization of each yarn before clamping.
Drop pins, serrated bars, healdwires, healdframes and reeds must be clean thoroughly
before drawing in.
Strict checking and immediate disposal of damaged drop pins, serrated bars,
healdwires, healdframes and reeds are required to improve weaving efficiency.
Application of lamination sheet in drawn set reduces gaiting time considerably and
also ensures less end breakages during gaiting
process.
A good understanding of Draft, Denting Plan
and Design is very much needed to avoid any
drawing in mistakes thus periodic training to the
operators is must.
Before handing over to weaving, a drawn set
must be checked properly. Preparation of checklist and rigorous follow-up will help in
this.
Best Practices in Textile Designing
Textile designing involves producing patterns for cloth used in clothing, household textiles
such as towel, upholstery and decorative textiles such as curtains / carpets. The field
encompasses the actual pattern making as well as supervising part or all of the production
process. Combination of colours and weaves play major role in textile designing.
In Designing following practices must carry out for smooth functioning in weaving.
Total ends / repeat should not be odd otherwise it will create problem in warping
during leasing.
Use bleach yarn for reactive dye shade instead of grey yarn.
Do not use very close shade adjacent to each other especially in fila-fil designs.
For combination weave like Plain + mix weave; take plain weave always in front heald
frame.
Don’t take more than 1800 ends in one heald frame.
Different color ends should not be taken in same dent where lifting is same like mock
leno, oxford, matt and rib weave.
Take selvedge ends from bottom beam in case of double beam design.
Best Practices in Weaving Process
Weaving is the process of interlacing two sets of yarns at right angles. The threads which lie
along the length of the fabric are known as warp threads, while those which lie across the
width are known as weft threads. More
technical names for these same threads are ends
and picks respectively. The weaving or
interlacing of warp and weft threads is
accomplished with a machine known as loom.
In order to interlace warp and weft threads to
produce a fabric on any type of loom, following operations are necessary.
Shedding: separating the warp threads into two layers to form a tunnel known as the
shed.
Picking: passing the weft thread through
the shed.
Beating-up: pushing the newly inserted
length of weft, into the already woven
fabric at a point known as the fell.
After all these operations took place, a weaving cycle is completed. Weaving cycles are
repeated over and over again until the cloth reaches the desired length.
In weaving following practices must carry out for better productivity and quality of the fabric.
Apply count and shade details on each package holder of weft creel to avoid mixing of
weft during weaving.
Warp patterns in the fabric must check with the help of swatches.
Display of denting and drawing plan on loom will help to reduce the weaver related
defects like wrong denting and wrong drawing.
To avoid Starting mark defect in the fabric starting mark marking must be done after
startup of new sort.
Apply standard machine setting after
each gaiting process.
Always monitor and maintain standard
RPM on loom.
Always do correct drawing and denting
of false selvedge to avoid fabric defects
and warp brakes at selvedges.
Always knot tail end of running weft package to start end of new weft package to
avoid weft brakes.
Always use four accumulators for better mixing of weft in the fabric to avoid fabric
defect i.e. weft bar and shade variation.
Do online checking of fabric at regular interval to avoid any continuous defect.
Best Practices in Maintenance
In foregoing discussion only best operational practices are discussed but in order to enhance
the probability of accomplishment of final goal of productivity and quality the best
operational practices need to be supported by good maintenance management. Ideally,
maintenance is performed to keep equipment and systems running efficiently for at least
designed life of the components. The design life of most equipment requires periodic
maintenance like Belts need adjustment; alignment and proper lubrication on rotating
equipment and so on. In some cases, certain components need to be replaced and therefore a
maintenance manager has to do following types of maintenance activities.
1. Breakdown Maintenance: “run it till it breaks”
2. Preventive Maintenance: “Periodic checking, adjustment and replacement”
3. Predictive maintenance: “ Maintenance on actual condition of the machine components
by judging performance, abnormal worn-out, noise & vibration rather than on some
preset maintenance schedule”
Preventive and Predictive Maintenance are the best maintenance practices over the
Breakdown Maintenance because
It Reduces equipment or process failure.
Flexibility to allow maintenance periodicity.
Increases component life cycle.
Estimated 12% to 18% cost savings over Breakdown maintenance.
Best Practices in Fabric Inspection
After the production of fabric from loom, woven out fabric sent to inspection department for
checking and grading. Men ding is a tool for removing fabric defect manually; similarly fabric
inspection is a tool for satisfying internal as well as external customer by mapping fabric
defects in the fabric. External customer can benefit by getting the products as per the
specification provided while internal customer benefit by knowing the reason for any down-
gradation and can thus correct the same. Fabric inspection also mirrors the packing
percentage and associated value losses due to down-gradation. A systematic approach of
inspection is important for proper and timely feedback to all pre production activities like
weaving, weaving preparatory, yarn dyeing and spinning. From weaving department cloth
rolls are sent for inspection at various stages of fabric production i.e. just after the starting of
new sort (first piece), in between the running sort (running piece) and at the finish of sort (last
piece).First priority must be given to first piece because
it will help to rectify fabric defect immediately after the
production start and also helps to raise an alert to
backward process. Next priority must be given to those
cloth roll for which inspection or quality control
department has already raised alert and then after
running piece and last piece of the sort.
There are many inspection practices and of them four
point inspection practice has got wide acceptance and is followed globally by fabric and
garment manufactures.
Basic requirement of Four Point Inspection System is as follows.
The light source must have perpendicular to the
surface of the fabric and the fabric runs at an
angle of 45 degree.
The inspection area surface illumination level
shall be a minimum of 1075 lux.
Inspect the fabric at a distance of one meter,
while the fabric is in motion.
FOUR POINT INSPECTION SYSTEM:
Assign defect points based on the length of the defect as mentioned in the following
table.
Defect Length ( Inches) Defect Point Category
Up to 3 1 Minor Defect
3 to 6 2 Minor Defect
6 to 9 3 Medium Defect
Over 9 4 Major Defect
Maximum 24 defect points are permissible in a 100 square meter of fabric.
Only 20 numbers of defects are permissible in 100 square meter of fabric.
Only 4, four point defects are permissible in 100 square meter of fabric.
No Major defect is allowed for first and last one meter of cloth roll.
Holes with ¼ inches or more considered as cut able defect.
Conclusion
Going forward every weaving mill needs to do periodic brainstorming sessions with work
force on each activities which is carried out in day to day work and find out the best ways to
do each activities. A continuous education / training of work force will further improvise the
best practices. Periodic brainstorming on Standard operating procedures (SOPs) of every
activities and strict adherence to SOPs are very much essential. These good practices in
process will help to enhance the productivity, quality of fabric, reduction of manpower
requirement and stress.