ADVANCES IN WEAVING TECHNOLOGY AND LOOMS http://www.pdexcil.org/news/40N1002/advances.

htm

ADVANCES IN WEAVING TECHNOLOGY AND LOOMS

S. Rajagopalan
S.S.M. College of Engineering, Komarapalayam.

Introduction

The weaving is a process of formation of fabric with interlacement of two or more

sets of yarns using a stable machine called loom. Human beings have started using
the woven fabrics since the drawn of history. If we exclude the stone age period,
we may conveniently say the history of civilization is also, to some extent, the
history of weaving. Aitken says there is evidence that the Egyptians made woven
fabrics over 6000 years ago. Though primitive civilizations used coarser threads to
make fabrics which were crude and coarse, there are references of fine fabrics made
from filament of silk in China. Silk was one of the most important product in China
4000 years ago. In India too, there existed some of the finest hand woven fabrics.
There are some references in Tamil literature, that the great poet, Thiruvalluvar
was a hand loom weaver.

Development of Handlooms

It is still not certain when the weaving process was introduced to human society. It
is clear from many historical records that weaving originated long before the time
of Jesus Christ. Except few activities else where, the major developments in textile
took place in England. In England the major shift from agriculture to woolen
industry came in the 14th century. During all these years and a few hundred years
after 14th century, the cloth was produced on hand-looms which were not
equipped with fly shuttle. Prior to Industrial Revolution, woven fabrics was
produced by atleast two people employed on loom.

In 1733, John Kay invented the fly shuttle which enabled weft to be inserted more
rapidly. John Kay, a weaver, further incorporated a mechanism with which, a
weaver could sit at the centre of the loom and merely pull the handle to make the
shuttle move from one end of the fabric to insert a weft thread.

As a result of increased weaving speed, the hand spinning method of yarn

production could not meet the requirement of fly shuttle looms and subsequently
the mechanical spinning also developed rapidly in Britain with Hargreave's
spinning Jenny (1770), Ark Writh's spinning machine (1769) and cromption
spinning mule (1779). The development of the mechanical spinning system induced
further developments in the loom. Edmund Cart Wright, an English clergy man,
invented a so called powerloom which could be operated from a single point by
two strong man.

Development in Powerloom

Earlier version of powerloom were run by two man. Fortunately steam power was
available by 1765. Soon powerlooms were driven by steam and most of the wooden
parts were replaced with iron. After the steam engine and cast iron in early 1800,
great attention was paid to increasing productivity of the machine. To help achieve
the increase in productivity, William Radeliffe patented a dressing frame in 1803
for sizing and drying the warp threads prior to winding on to a weavers beam. Fast
development in the loom took place and by 1821 there were over 50,000 looms in
operation in some 32 mills in the north of England. In just over 10 years from that
date, the number had increased to some 1,00,000 and the basic loom had almost

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developed to the machine we know today. Also between 1819 and 1842 the
average speed of the powerloom had increased from 60 to 140 picks per minute
with the rise on productivity, as a result England became world's richest industrial
power.

Developments in Automatic Loom

Traditional looms then were stopped every few minutes in order to replace the
empty weft pirns or cop in the shuttle and this limited the number of looms, a
weaver could operate to about four. James Northrop, an English man who
emigrated to America and worked for the Draper Corporation, completed an
automatic weft transfer system which replaced the weft pirn in the shuttle without
slowing or stopping the loom in 1889. This mechanism enabled the weaver to tend
16 looms. The Northrop Automatic looms quickly came to use in America, so that
by 1930, 90% of the American looms were automatic compared with only 5% in
Britain.

Similar developments took place elsewhere also, Ruti, a major loom maker of
Switzerland manufactured automatic bobbin changing Northrop loom in 1898. In
Japan also, Toyoda, Sakamoto, Tsudakoma, etc also developed shuttle looms with
automatic weft transfer. After World War II, more productivity and efficiency were
essential to overcome increasing labour costs in Western countries. It was also
realised that more productivity is the key to reducing manufacturing costs of the
loom. All attempts were concentrated to studying various factors affecting speed of
the loom and the loom with higher speed were made available.

Limitations of Shuttle Looms

Despite the relatively high speed and efficiencies in loom with conventional
picking, productivity of these machines will continue to be limited as long as their
fundamental constructions involved the use of a shuttle propulsion. Vincent has
shown that the power required for picking is proportional to the cube of the loom
speed. If the loom speed is increased from 200 to 300 picks per minute, the power
requirement would increase by a factor of (3/2)3 i.e. 3.4 times approximately. This
results in following disadvantages

1. Greater strain imposed on the picking mechanism, thus rendering it liable to

frequent failure.

2. Greater amount of noise and vibration.

3. Because of superior energy in shuttle, greater strain is again imposed on the

checking mechanism.

4. The movement of shuttle will be more difficult to control and there will be a
greater possibility of its ejection from the loom.

The dynamic problems created by the picking and checking mechanism and the
inherent process of pirn winding for shuttle looms had encouraged the loom
makers to develop alternative means of weft insertion in which heavy shuttle is not
projected forwards and backwards across the width of the loom. It is customary to
refer these looms as shuttleless looms. The various shuttleless loom that have been
developed over a period of about 50 years can be classified into various groups.

* Projectile Looms

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* Rapier Looms

* Fluid Jet Looms

* Multiphase Looms

Advances in Weaving Technology

The emphasis on productivity and quality has developed the weaving technology
very much and as a result the working hours required to weave fabric from loom
have been reduced from about 20 to 0.25 during the last 125 years, and in the last 50
years there has been a reduction of 95% in operative hours per standard unit
produced. Majority of the developments are taking place on the shuttleless looms
in the following directions :

1. To increase productivity of the loom.

2. To make the looms more flexible for different kinds of fabric.
3. To reduce the down time for changing style, etc.
4. Application of electronic control mechanisms to increase automation
5. Development of accessories such as dobby, jacquards, etc.

In addition to these, the newer looms are simple in design, the motions are more
reliable, consumes less energy and have lower maintenance cost.

Productivity

The production rates of the various types of looms are presented for comparison in
Table -1:

Table - 1

Production Rate of Various Types of Looms

Available width Speed in Weft insertion

Loom Type
in cm rpm Rate(picks per minute)
Projectile
Sulzer Ruti
P7100 190-540 320 1100-1200
P7200 190-540 430 1500
STB Russia 180-330 300 750
Rigid Rapier
SACM 150 550 1100
Dornier 150-400 460 1000
GUNNE 230 330 1200
Flexible Rapier
Somet 165-410 550 1300
Vamatex 160-380 510 1300
Sulzer Ruti 110-280 325 1200
Nuovo Pignone 220-420 440 1000
Water Jet
Metor SPA 230 1000 1600

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Nisson 150-210 1000 2000

Tsudakoma 150-210 1000 2000
Air Jet
Sulzer Ruti upto 300 750 1600
Picanol Omni 190-380 800 1800
Picanol Delta 190 1100 2000
Toyoda 150-330 850 2000
Tsudakoma 150-340 1000 2200
Lakshmi Ruti 190 500 1200
Dornier 430 600 2520
Linear
Multiphase
Elitex About 190 1100-1600 2000-3000
Drum type
Multiphase
Sulzer M8300 190 3230 6088(Plain)
170 2430 4118(Twill)

Out of these single phase looms, Air jet loom is having maximum speed and
maximum weft insertion rate. Because of the very high quality of yarn required, the
yarn must be of very high standard, otherwise the loom stoppages due to warp
breaks and weft breaks will be high. The efficiency achieved will be in the order of
93 to 95%.

Other looms like projectile and repair will give an efficiency of about 90 to 95%. The
cover of the fabric in air jet will not be as good as projectile and rapier looms.
Efficiency in multiphase loom is in the order of 90 to 95%

These are the speeds obtained by the weavers at commercial level. The main reason
for targeting higher productivity is to reduce the cost of production, especially
labour cost. The increase in speed is being achieved the improvement in all major
functional parts of the modern looms

Table-2

Variety of Fabrics Woven on Specific Looms

Weft
Loom Type Field of application
selection
Projectile
Sulzer Ruti
P7100 4 colours Sheeting dress material filament weaving
P7200 4 colours
STB Russia 4 colours
Rigid Rapier
up to 4 Yarn dyed fancy fabric manufactured such as
SACM
colours Suiting,shirting smaller batch production

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up to 16
Dornier
colours
up to 6
GUNNE
colours
Flexible
Rapier
up to 8
Somet spun & filament dress material
colours
up to 8
Vamatex
colours
up to 8
Sulzer Ruti
colours
Nuovo up to 8
Pignone colours
Water Jet
Weaving of filament,twisted & texturised filament
Metor SPA Single colour
sarees,dress materials
Weft
Nisson
mix,1*1,2*2
Weft
Tsudakoma
mix,1*1,2*2
Air Jet
up to 3 Light gauge & sheeting,spun & filament fabric
Sulzer Ruti
colours corduroy
Picanol
6 colours
Omni
Picanol Delta 2 colours
Toyoda 6 colours
Tsudakoma 6 colours
Lakshmi Ruti 2 colours

Today the market particularly demands wide variety as much as possible at the
lowest possible cost. These machines provide the feature such as :

- The possibility of weaving more difficult products in terms of yarn employed and
also in combinations.

- Application potential in all weaving sectors.

(Sulzer Ruti 6300 rapier loom will weave not only fashion, fabrics with us many as 8 weft
colours but also furnishing fabrics, simple print base fabrics and denims as efficiently as
light to heavy weight industrial fabrics.)

The terry plus airjet terry weaving machines of Gunne not only permit greater pile
height and heavier fabrics, it also offers greater flexibility in operation with the
ability to change the fabric width and pile height. On the machine the drawing
width can be changed using the same reed, simply by shifting the weft stop motion

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and the weft cutter. The pile height is programmable within the same fabric.
Special fabric constructions with different pile heights on front and back are also
possible. For Sulzer P7300 projectile looms a variety of back rest roller and cloth
take up systems are available to suit the density and the type of fabric woven.

Minimum Down Time

Many of the weaving machine manufacturers offer quick style change (QSC)
system. The basic idea of these developments is to prepare module outside the
weave room and keep them ready for a switch over with empty module in the
weaving machine. Dornier demonstrated quick style changes from a fine worsted
fabric to a pure cashmere fabrics in less than 30 minutes. Similarly, almost all major
weaving machine makers offer their own version of QSC. Dornier offers Fast Dobby
Change (FDC) which allows a mill exchange a dobby shedding for a cam drive
when a basic style is being woven and higher shedding machine speeds are
possible. The exchange times is not more than 1.5 hours per occurrence. The saving
in time with QSC in Picanol is illustrated with an example in Table-3

Table-3 Average Loom Stoppage Time (in minutes)

With QSC Without QSC

Stop factor
system system
Waiting time 5 5
Loom unloading 10 40
Trolley waiting time 10 40
Loom loading 8 25
Reed,hardness
6 60
locking
New style setting 15 15
Loom restart 5 25
Interference loss 4 12
Total 74 203

The down time is getting reduced to about one third with Quick Style Change
(QSC) system.

Electronic Control Mechanism :

The use of central microprocessor control system and automatic functional with
bidirection communication and diagnostic features are the common features of
most of these latest weaving machines. Sulzer Ruti P7100 with central
microprocessor control, electronically controls progressive weft break, automatic
weft feed backup which switches over to a feeder head with intact weft intact weft
thread in the event of weft break, at the same time informing the weaver an optical
automatic weft break repair and package handling system.

In repair machines electronic control weft tensioner reduces the yarn tension
specially during insertion. The opening and closing time can be selected according
to the material usually at yarn pick up. Automatic package switching device
prevents the machine from being stopped in the event of a weft break between the
package and the weft feeder. The microprocessor switches over immediately to a
reduced number of packages in the circle, so that the machine continues to run.

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Electronically controlled warp let off and cloth take up units ensure high degree of
fabric regularity and prevent all kinds of start and stop marks. Electronic
monitoring control system have simplified the communication with the machine
and facilitate its easy handling by any one concerned with the operation of the
machine e.g. weaver, technical, maintenance, personnel, etc.

In airjet weaving machine electronic let-off maintains consistent warp tension from
full beam to empty beam. Electronic cloth take up generates a pick density
resolution of 0.1 picks/cm and holds it constant, under all operating conditions.

In terry plus airjet terry weaving machine of Gunne Web Machinen Fabric GMBH
& Co. The microprocessor monitors the entire insertion cycle and keeps all the
different elements perfectly synchronized.

Other Developments

(a) Tuck-in-Devices

Some of the important development are new tuck in motions based on pneumatic.
The principle of pneumatic trucking in is the use of air to hold the filling end and
then forcing the filling end to be tucked in, in the next shed, by air. In airjet
weaving the automatic weft repairer which repairs the weft break and starts the
machine automatically is made simple by using mechano pneumatic device. It is a
positive factor in higher weaver allocation and increased efficiency. Dornier
exhibited their pneumatic tucker on two airjet weaving machines (LTN F8/J and
LWV2/E). Tsudokama demonstrated their ZNT needleless tuck-in on two airjet
weaving machine. Somet showed its patented tucking motion on a clipper airjet
machine. Elimination of tuck in needle by pneumatic tuck in motion enables the
loom run much faster as compared to mechanical devices.

(b) Electronic Jacquard Head

Grosse has introduced its patented UniShed positive electronic jacquard head. The
shed formation in the UniShed is achieved by leaf spring. Each leaf spring is
connected to a heddle that controls one warp end. The leaf springs which are
controlled by actuators control the bottom shed as well as the top shed (positive
shed type). The dimensions of the jacquard head and the individual control of each
heddle (warp end) allow the heddles to be set vertically. These settings permit the
elimination of harness cords, hooks, magnets, pulleys, pull down springs and more
significantly, the gantry. The jacquard head is mounted directly on the side frame
of the weaving machine, thus allowing quick style changes.

(c) Jacquard Shedding Mechanism

Staubli's Unival 100 electronic jacquard shedding mechanism offers a new concept.
The shed formation is achieved by controlling each individual warp end with a
stepping motor. The harness cord / warp end selection is performed electronically
and hence fabric design is achieved in the same way as any electronic jacquard
system. The design of the Unival 100 permits the elimination of hook and the
gantry.

(d) Weft Package Handling

Complete automatic weft package handling, loading the package frame and
package changing can be incorporated on Sulzer Ruti projectile weaving machines

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and Tsudakoma Airjet weaving machines. These include automation equipment for
detecting the broken picks with drawing it from the open shed, correcting the cloth
fell position and restarting the machine. The entire cycle is completed in about 12
seconds.

(e) A Loom Developed by SITRA

The modern shuttleless looms not only produce faster, but also the cloth produced
by these looms possess much better quality as compared to conventional looms.
The main problem faced by the decentralized weaver is that imported shuttleless
looms are very expensive. In order to overcome this disadvantage to a
decentralized sectoer SITRA has developed a low cost rapier shuttleless loom with
a likely price tag of around Rs. 3.5 lakhs. The major advantages of this loom as
compared to ordinary loom are:

- the speed of the machine can be increased by 25%.

- when the four colour weft is used, the speed increase will be more than 40%
compared to drop box loom.

- weaving defects in fabric will be considerably reduced.

- since rapier machine feed weft yarn from cone, the process of pirn winding is
eliminated.

- 10 to 15% increase in efficiency is possible when compared to ordinary power

looms.

- higher work assignment is possible.

- because of low cost, power loom units can afford to install this machine.

SITRA has licensed M/s. Industrial Engineering Works (Ganga looms), Bangalore
to manufacture this machine.

(f) Other Attachments

To achieve minimum defects in fabrics, with increase in loom efficiency and to

meet the requirements of export quality fabric, the following additional motions
may be installed in ordinary power looms.

1. Electronic weft feelers.

2. Electro mechanical weft fork.

3. Electronic warp stop motion.

4. Sudden brake motion.

5. Positive let off motion.

These devices will increase the productivity, reduce fabric defects due to double
picks, weft cracks, starting marks, broken picks, uneven pick density, etc. The
approximate cost of these attachments is given Table 4.

Table 4

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Various Attachments and Their Costs

Sr No Name of the attachment Approximate cost

1 Electronic weft feelers 2000/-
2 Centre weft fork 4000/-
3 Electrical warp stop motion 4000/-
4 Brake mechanism 4000/-
5 Positive let off motion 9000/-
Total 23,000/-

The advantage derived like minimum defects, increase in production, improved

quality and increase in efficiency will enable the manufacturer to recover the
amount invested in a very short period. Moreover the loom allotted to a weaver
can also be increased depending on the variety woven.

So the improve quality, production, efficiency and to face competition when

textiles will be available from other countries also, the manufacturers have to
expeditiously modernize and tune up the operational efficiency of their existing
loom.

References

1. Shuttle Looms - Its Present Status by A. I. Thakkar. NCUTE Pilot Programme on

Weaving I - Shuttle looms Page. 47. (NCUTE, New Delhi, 1999)

2. Vincent J. J. Journal of Textile Institute, vol. JTI, 50 1959 Page 261.

3. Weaving - A Special Feature by Dr. Arindam Basu, SITRA in Indian Textile

Journal ITJ, June 2002. P. 23.

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