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`
National Institute of Fashion Institute, Kannur
Integrated Term ProjectOn
Dobby and Jacquard Loom
Submitted
byAditya Kumar
Shreya Sahu
1
Acknowledgement
We would like to express our heartfelt gratitude to our mentor Mr. D Rajashekar
without whose support and proper guidance this Integrated Term Project would not
have been so.
We are also extremely thankful to Mr. Pari J, the
co-ordinator for making this endeavour possible. Without his proper guidance this
learning project would have not been fruitful.
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National Institute Of Fashion Technology, Kannur
CERTIFICATE
This is to certify that Integrated Term Project work entitled “Dobby and jacquard
Loom” is a bonafied work completed by Aditya Kumar and Shreya Sahu of
Semester-II, (B.FTech, Apparel Production) from the National Institute of Fashion
Technology, Kannur.
Mr. D Rajashekar Mr. Pari J
Associate Professor Co-ordinator, ITP
Mentor, B.FTech (A.P)
NIFT, Kannur NIFT, Kannur.
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INDEX
1. Introduction………………………………………………………06
2. Weaving…………………………………………………………. 07- 13i. Primary Motionii. Secondary Motioniii. Auxiliary Motion
3. Looms…………………………………………………………….14 – 21
4. Dobby Looms……………………………………………………22 - 28i. Introductionii. Shedding Mechanismiii. Types of dobbyiv. Advantages of dobby loomsv. Advancements in dobby looms
5. Jacquard Looms……………………………………………..…29 - 51i. Introductionii. Historyiii. Classification iv. Principle parts v. Mechanism connecting the engine to the loomvi. Conventional Mechanismvii. Functionviii. Problemsix. Advantages and Disadvantages of Jacquardx. Comparison between SLSC, DLSC and DLDC Jacquardsxi. Advancements in the Jacquard
6. Conclusion……………………………………………………..
7. Integration………………………………………………………
8. References……………………………………………………
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INTRODUCTION
Homo sapiens are believed to have first evolved about 200000 yrs ago. For almost all of this time, the new species clothed itself in skins and furs torn from the bodies of animals that had been slaughtered for food. The production of fabric which requires a considerable sophistication of civilization began, by comparison, far more recently. Earliest surviving fragments of cloth made of flax were found in Egypt dating 4500 BC. The production on a larger scale started with a major new invention – weaving. Then it was a simple process when rigid fibres such as reeds are being used. But rigid fibres do not make comfortable clothing. This needed to be produced from soft, flexible yarns. This lead to the invention of looms on which it can be achieved in a neat and convenient way. Loom is best defined as any frame or contrivance for holding warp threads parallel to permit the interlacing of the weft at right angles to form a web.
Myriads of appliances have been devised for the purpose of making the loom effective as the loom is the most necessary of the tools, the means of supplying one of the main indispensable needs of mankind-fabric. In consequence of the Industrial Revolution, the late 18th century had witnessed a considerable expansion in the automation of processes that had once been the preserve of small groups of highly skilled workers employed in so-called ‘cottage industries'. Moreover the need to add aesthetic patterns and designs to the fabric was also in demand.
This led to the evolution of Dobby and Jacquard loom. A Dobby Loom is a type of floor loom that controls the warp threads using a device called a dobby. Small, geometric figures can be woven in as a regular pattern on this loom. Most of the furnishing fabrics are woven by this method. But only simple designs were possible on this. Man was not satisfied and wanted to do elaborate designs on the fabric with the same independence that an artist enjoys while painting. This desire also got fulfilled with the invention of Jacquard loom.
Jacquard loom has no limitations on the type of design that can be automatically woven. It can be ‘programmed’ to create any desired design by using punch cards.
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In this system each individual warp can be lifted in a pre-planned sequence to produce a particular design on the fabric.
In addition to making various geometric as well intricate patterns and designs possible, these looms also helped weavers to get rid of normal draw looms which were maddeningly slow and tedious to use and made decorated fabrics affordable to a greater portion of the population. These lower prices are letting the average person be able to display these fine works in their homes and enjoy something once reserved for only the rich.
WEAVING
Weaving is the most ancient of the great arts, appearing at the dawn of history, virtually inseparable from the true culture. From the rough fish weirs to the most elaborate baskets, from the coarser fabrics of flax to the gossamer webs of cotton and silk, it has sustained and beautified man’s life from the night of history to the latest passing hour; It is the veritable nurse of civilization.
In general, weaving involves the interlacing of two sets of threads or yarns at right
angles to each other: the warp and the weft, to produce a two-dimensional fabric.
The warps are held taut and in parallel order, typically by means of a loom, though
some forms of weaving may use other methods. The loom is warped (or dressed)
with the warp threads passing through heddles on two or more harnesses. The warp
threads are moved up or down by the harnesses creating a space called the shed.
The weft thread is wound onto spools called bobbins. The bobbins are placed in a
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shuttle which carries the weft thread through the shed. The raising/lowering
sequence of warp threads gives rise to many possible weave structures from the
simplest plain weave (also called tabby), through twills and satins to complex
computer-generated interlacing. The cloth produced can be plain (in one color or a
simple pattern), or it can be woven in decorative or artistic designs, including
tapestries. The appearance of the fabric is determined by the uniformity of the of pick
spacing or the number of picks per inch of the cloth (ppi); the packing density of the
warp and weft in the body of the fabric or the fabric cover factor; the ratio of the warp
density to the weft density or the sett; the different color warp and weft used for
weaving, and the designs formed by changing the movement of the warp threads.
The productivity depends not only on the mechanization, but also on the quality of
the cloth and what kinds of design it has. Making complex designs on the fabric
lowers the productivity, but the resulting signs mark-up in the price of the fabric much
more than offsets the extra labor involved. With mechanisms such as the dobby and
jacquards, the productivity, depending on the complexity of the design, can go down
significantly, but the returns are very high.
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On the conventional loom, there are three basic motions that are carried out for
weaving a fabric. They are:
I. PRIMARY MOTIONS
The primary motion itself consists of three basic operations which form a continuous
cycle whether in the simplest hand loom or in the most complicated automatic
machine.
These primary motions are:
Shedding
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Picking
Beating up
In the absence of primary motions, Weaving is never possible.
1. SHEDDING
The raising and lowering of warp yarns is carried out by the heald frames that hold
the ends by means of heald and heals eyes. As the heald frames move up and down
an opening is formed between the ends called a SHED. This first weaving operation
is therefore known as shedding.
2. PICKING
Picking is the insertion of a weft thread across the warp yarns through the shed. On
raising the heald frames which in turn raises the warp yarns, the filling yarn is
inserted through the shed by a carrier device which is a shuttle. A shuttle with a weft
pirn is passed through the shed and as it passes a length of weft thread is unwound
from the weft pirn and it remains in the warp shed.
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3. BEAT UP
Beating up is basically carrying forward of the last inserted pick of weft to the cloth
already woven that is up to the cloth fell. All the warp yarns pass through the heald
eyelets and through openings in another frame that resembles a comb and is called
a reed. With each picking operation the reed automatically pushes or beats each
filling yarn against the fell of the cloth.This third essential weaving operation is
therefore called beating up, or battening. It gives the fabric a firm compact
construction.
The picking and beating up operations are fixed no matter what type of fabric is
being produced but the shedding motion is variable and can be described as the
heart of weaving as it is here that the nature of interlacing or the weave is decided.
II. SECONDARY MOTIONS
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The secondary motions consist of two operations:
Take up
Let off
In the absence of secondary motions, longer length of fabrics is not possible.
1. TAKE UP:
With each shedding picking and beating up operation the newly constructed fabric
must be wound on the cloth beam. This process is known as taking up.
The take up process involves pulling the cloth forward after the beat up of weft,
maintaining the same pick density and spacing throughout weaving of the cloth and
winding the woven cloth onto a roller. Thus, the take up motion determines the
speed of cloth withdrawal and therefore, the density of spacing of the weft picks in
the cloth.
2. LET OFF:
As the cloth is rolled up, the warp ends from the warp beam must be unwound so
that yarns will not be stretched to the point of breakage and the cloth fell position is
maintained at the desired point keeping the average warp tension constant. This
function is accomplished by the let off motion.
Thus the let off motion determines the rate at which the warp is fed forward and the
tension of the warp yarn. The tension is largely responsible for the configuration of
warp.
III. AUXILIARY MOTIONS
In order to produce good quality of cloth and to prevent damages it is necessary to
have some stop motions provided on the loom which are:
Warp stop motion
Weft fork stop motion
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Warp protector motion
Temples
Brakes
In the absence of auxiliary motions one can weave longer lengths of fabric but not
fault free fabric.
1. WARP STOP MOTION
The purpose of warp stop motion is to stop the loom when a warp thread breaks.
The loom also stops when a warp thread becomes excessively loose.
If a broken warp thread is not detected immediately it will tend t get entangled round
adjacent threads thus causing more end breakages or will create a fault known as
float in the woven cloth.
There are two types of warp stop motions:
Mechanical
Electrical
2. WEFT FORK STOP MOTION
This motion enables to stop the loom immediately after a weft break or weft running
out. In case the loom is allowed to run even after the weft breaks there will be no
woven cloth except long threads of warp.
There are two types of weft fork stop motions:
Side weft fork stop motion
Centre weft fork stop motion
3. WARP PROTECTOR MOTION
The function of the warp protector motion is to stop when the shuttle fails to reach
the shuttle fails to reach the shuttle box during picking.
There are two types:
Loose reed
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Fast reed
4. TEMPLES
In order to hold fast the width of the cloth as equal to as possible as possible to the
width of the warp of the reed, temples are provided near the fell of the cloth so as to
oppose the natural contraction taking place at the cloth fell.
Also the function of the temples is to prevent breakage at selvedge ends.
The types of temples are:
Full width temples
Nipper temples
Sun temples
Roller temples
Ring temples
Combination of different types
5. BRAKES
A brake is a device by means of which artificial frictional resistance is applied to a
moving body in order to stop the motion of a loom.
The most commonly used brakes in loom:
Shoe brake
Band brake
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LOOM
The word ‘loom’ is derived from the old English ‘geloma’ which means simply ‘tool’ or ‘utensil’.
A loom is a machine or device for weaving thread or yarn into textiles. In practice, the basic purpose of any loom is to hold the warp threads under tension to facilitate the interweaving of the weft threads. Loom is best defined generally as any frame or contrivance for holding warp threads parallel to permit the interlacing of the weft at right angles to form a web.
It is generally agreed that the weaving of textiles on looms began during the Neolithic Age in Europe. Vertical looms were probably the first to be invented. The earliest representation of a loom dated 5000 BC illustrates a horizontal ground loom from Badari. On this loom the warp is stretched horizontally between two beams pegged a few inches above the ground. The ancient Egyptians and Chinese used looms as early as 4000 BC. As long as the material to be woven was fairly rigid, no additional apparatus was necessary. How the loom developed was to a large extent dependent on what fiber was used for the warp. The history of the evolution of the loom is a history of minor innovations, mostly designed to increase the speed of fabric production.
The entire weaving process can be simplified into three basic operations- holding the warp under tension, opening and changing the shed, and inserting and beating up the weft. All the improvements and changes in loom design and construction are concerned with one or more of these problems. Once weaving entered the commercial arena, doing it better usually meant doing it faster. Today, pattern cards for Jacquard weaving can be cut by computer and woven at the rate of 200 picks per minute. On other modern looms water jets can propel weft yarn through a shed at the rate of 1000 picks per minute. The handloom, which began as a mechanism to furnish necessities, has survived as a specialized tool of the handicraftsman who furnishes art of luxury fabrics.
Looms can range from very small hand-held frames, to large free-standing hand looms, to huge automatic mechanical devices. The precise shape of the loom and its mechanics may vary, but the basic function is the same.
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Types of looms
On the basis of picking mechanism looms are divided into two types:
1. Shuttle looms
2. Shuttle less looms
1. Shuttle loom
It is the oldest and conventional type which uses a shuttle that contains a
bobbin of filling yarn. As the shuttle is batted/passed across the loom it leaves
a trial of filling at the rate of about 110 to 225 picks per minute.
Disadvantages
Shuttle sometimes causes abrasion on the warp yarns as it passes over them
and sometimes cause thread breakages
This in-turn results in machine stoppage in-order to tie the broken yarns
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It operates more slowly and are noisy
2. Shuttle-less Looms
It is developed to overcome the disadvantages in Shuttle looms. Each type
uses a different type of picking mechanism.
Projectile/Missie loom
It was developed in 1950’s in Switzerland. In this picking action is
accomplished by a series of small bullet-like projectiles which grip the filling
yarn and carry it through the shed and then return empty. All filling yarns are
inserted from same side of the loom. A special tucking device is used to hold
the ends of the filling to from the selvedge. Speed of 300 ppm can be
achieved on this loom. It is less noisy compared to shuttle loom.
Rapier Looms
It is competitors to missile loom. There are several types of this loom. One type uses
one long rapier device that reaches across the width of the loom to carry the filling
from one side to other side of the loom. Another type uses a double rapier, one on
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each side of the loom. Rapier construction may be of rigid, flexible etc. In each case,
one rapier feeds the filling yarn halfway through the shed to the arm on the other
side of the other rapier. It is more efficient. The speed ranges from 200 to 260 ppm.
Water-Jet Looms:It was first developed in Czechoslovakia in 1950’s and
subsequently refined by Japanese in the 1960’s. It is designed to weave faster
and to relieve the tension on the filling yarn as it is carried through the shed. A
pre-measured length of filling yarn is carried across the loom by a jet of water. It
operates at high speeds of about 600 ppm and noise levels are lower than
shuttle, missile and rapier. Disadvantage is that the water jet looms are restricted
to production of fabrics made of yarns that are not readily absorbent such as
filament yarns of acetate, nylon, polyester and glass. But it can produce superior
quality fabrics that have good appearance.
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Air-jet Looms
It was invented in Czechoslovakia and later refined by Swiss, Dutch and
Japanese. It is designed to retain the tensionless aspect of picking action of
water-jet while eliminating the problems caused by the use of water. It uses a jet
of air for insertion of filling yarns at the rate of about 600 ppm. It requires
uniformity in filling yarns and suitable for heavier yarns as the lighter yarns are
difficult to control through the shed.
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Circular Looms
It is specifically designed to produce tubular rather than flat fabrics. It requires shuttle device that circulates the filling in a shed formed around the machine. It used primarily for bagging material.
Other types include:
Handloom
The earliest looms were vertical shaft, with the heddles fixed in place in the shaft.
The warp threads pass alternately through a heddle and through a space between
the heddles, so that raising the shaft will raise half the threads (those passing
through the heddles), and lowering the shaft will lower the same threads -- the
threads passing through the spaces between the heddles remain in place.
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Haute lisse and basse lisse looms
Looms used for weaving traditional tapestry are classified as haute lisse looms,
where the warp is suspended vertically between two rolls, and the basse lisse looms,
where the warp extends horizontally between the rolls.
Power looms
The first completely automated loom was made by Jacques Vaucanson in 1745. It
was used for silk but didn't develop further. Edmund Cartwright built and patented a
power loom in 1785, and it was this that was adopted by the nascent cotton industry.
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Powered looms were shuttle-operated for two hundred years. In the early part of the
20th century the faster and more efficient shuttle less rapier looms and air looms
came into use. Modern industrial looms can weave at speeds 2000 Weft insertions
per minute. Today, advances in technology have produced a variety of looms
designed to maximize production for specific types of material. The most common of
these are air-jet looms and water-jet looms. Computer-driven looms are now also
available to individual (non-industrial) weavers.
Knitting looms
Knitting looms (also known as Amish looms or knitting boards) were recently
popularized in crafting circles by the Knifty Knitter system. Knitting looms are a
descendant of the frame loom. Grooved pegs are spaced along a central frame.
These pegs are wrapped with yarn in various ways, and then the knitter uses an
angled hook to pull the wrapped yarn over the top of the peg, resulting in a fabric
with stitches similar to a needle knitted item.
DOBBY LOOM
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INTRODUCTION
A Dobby Loom is a type of floor loom that controls the warp threads using a device
called a dobby. Dobby is short for "draw boy" which refers to the weaver's helpers
who used to control the warp thread by pulling on draw threads.
A dobby loom is an alternative to a treadle loom. Each of them is a floor loom in
which every warp thread on the loom is attached to a single shaft using a device
called a heddle. A shaft is sometimes known as a harness, but this terminology is
becoming obsolete among active weavers. Each shaft controls a set of threads.
Raising or lowering several shafts at the same time gives a huge variety of possible
sheds through which the shuttle containing the weft thread can be thrown.
A manual dobby uses a chain of bars or lags each of which has pegs inserted to
select the shafts to be moved. A computer assisted dobby loom uses a set of
solenoids or other electronic devices to select the shafts. Activation of these
solenoids is under the control of computer program. In either case the selected
shafts are raised or lowered by either leg power on a dobby pedal or electric or other
power sources.
On a treadle loom, each foot-operated treadle is connected by a linkage called a tie-
up to one or more shafts. More than one treadle can operate a single shaft. The tie-
up consists of cords or similar mechanical linkages tying the treadles to the lams that
actual lift or lowers the shaft.
On treadle operated looms, the number of sheds is limited by the number of treadles
available. An eight shaft loom can create 254 different sheds. There are actually 256
possibilities which is 2 to the power eight, but having all threads up or all threads
down isn't very useful. However, most eight shaft floor looms have only ten to twelve
treadles due to space limitations. This limits the weaver to ten to twelve distinct
sheds. It is possible to use both feet to get more sheds, but that is rarely done in
practice. It is even possible to change tie-ups in the middle of weaving a cloth but
this is a tedious and error prone process so this too is rarely done.
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With a dobby loom, all 254 possibilities are available at any time. This vastly
increases the number of cloth designs available to the weaver. The advantage of a
dobby loom becomes even more pronounced on looms with 12 shafts (4094 possible
sheds), 16 shafts (65,534 possible sheds), or more. It reaches its peak on a
Jacquard loom in which each thread is individually controlled.
A dobby can be employed in working forty-eight heald shafts. Each heald shaft has
its own pair of hooks, the front to the lift and the back one to depress.
Lags And Pegs
At the side of the dobby loom and touching the surface of the spring wires, is a
cylinder, carrying upon it a chain of flat wooden bars, named as lags. When in
working order, the lags are equipped with pegs which fill up certain holes, and
pressed against the spring wires, pushing the front hooks over the front knife and the
back hooks off the back knife. The exact order in which the lags are pressed does
not matter.
There are many forms of lag, and different methods of operating them; in some
power-loom dobbies, the lags are displaced by cards. Being chains, lags may be of
any length, containing one, two, three, or as many repeats of a pattern as may
appear advisable.
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DOBBY SHEDDING MECHANISM
In dobby shedding, the heald frames are operated by jacks and levers. The order of
lifting and lowering of the heald frames, as per a lifting plan, is controlled by a pattern
chain that gives unlimited scope for weaving designs, repeating on large number of
picks. This mechanism can control upto 24 heald frames, depending upon the crank
arm length.
The design possibilities are:
Twill
Satin
Crepe
Honeycomb
Huck-a-back
Mock leno
Bedford cord
Double cloth
The disadvantages of dobby mechanism are:
a. The mechanism is complicated
b. Initial cost is high
c. Maintenance cost is high
d. Can produce design faults in woven fabric
e. Tend to limit the loom speed when compared to the tappet shedding
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TYPES OF DOBBIES
Dobbies may be right-handed or left-handed, according to the position of the treadle
on the hand loom or the driving rod on the power loom. In pegging, it is necessary to
consider which hand the dobby belongs to, the rule being that the first lag which
turns in towards the dobby mechanism is the first to be pegged.
THE KEIGHLEY DOBBY
One of the most useful of the dobbies operated on the power loom is known as the
Keighley dobby. This dobby has been a great favourite with weavers of all classes of
fabrics. In this, the levers are dispensed within the lag mechanism, and the lags are
set directly to at upon the hooks.
A Dobby with Needles
In some particular dobbies, the lag cylinder suffers in comparison with the card
cylinder and the pegs do not obtain the same degree of favor as the needles.
Dobby with horizontal needle
The machine known as the single lift dobby stills finds its use. The frame is placed
over the centre of the loom, the ends of the vertical hooks being above the middle of
the shafts. Each hook passes through the eye of a horizontal needle; as this needle
is the means of lifting the hook on or off the griffe. All the needles are contained
within the framing, perforated plates at front and back holding them in position while
allowing them for free motion to and fro.
There are numerous dobby machines of various forms and applications. In all,
however, all the essentials are similar. Centre shed, double-lift, cross-border, the
Blackburn, the Burnley, the closed shed and positive open shed dobbies in their
several forms exhibit great ingenuity.
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ADVANTAGES OF DOBBY LOOMS
1. The ability to handle much longer sequences in the pattern. A weaver working
on a tread led loom must remember the entire sequence of tread lings that
make up the pattern, and must keep track of where they are in the sequence
at all times.
2. The dobby appliance is of immense service to textile manufacture. The
compactness of the machine, the wide range of heald-shafts it can control and
the directness of the relation between the pattern design and the heald shaft
mechanism are qualities which place dobby among the most useful of
shedding appliances.
3. On a manual dobby the sequence that makes up the pattern is represented by
the chain of dobby bars. The length of the sequence is limited by the length of
the dobby chain. This can easily be several hundred dobby bars, although an
average dobby chain will have approximately fifty bars.
4. A computer controlled dobby loom (Computer-Dobby) takes this one step
further by replacing the mechanical dobby chain with computer controlled
shaft selection.
5. In addition to being able to handle sequences that are virtually unlimited, the
construction of the shaft sequences is done on the computer screen rather
than by building a mechanical dobby chain. This allows the weaver to load
and switch weaves drafts in seconds without even getting up from the loom.
6. The design process performed on the computer provides the weaver with a
more intuitive way to design fabrics seeing it on the computer screen is easier
than trying to visualize it by looking at the dobby chain. One such example of
Computer-Dobby loom is Leclerc Weavebird Computer-Dobby looms.
7. Dobby looms expand a weaver’s capability and remove some of the tedious
work involved in designing and producing fabric. Many newer cloth design
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techniques such as network drafting can only reach their full potential on a
dobby loom.
ADVANCEMENTS IN DOBBY LOOMS
All shuttle looms can be modified in such a way that weft can be inserted
continuously without frequent pirn change. This method can be used in all types
of plain looms attached with dobby and also with drop box/under pick/pick and
pick mechanisms.
The dobby mechanism can be used to change the color of the weft as and when
required. A special mail eye is fitted in the dobby and they are lifted so that the
required color weft can be drawn from the particular mail eye.
With this system one can weave half of the fabric with one color, another half with
a different color by keeping two different color threads in both sides of the cones.
By providing more number of cones of different colors at the feeding end one can
weave stripe or check patterns without drop-box mechanism.
The advantages of this system are numerous:
3. For wider width looms this system is very much suitable. Small
sectors in the country can increase their production without any
extra expenditure.
4. Using this method one can weave fabrics like cotton, rayon,
polyester, silks using normal plain power looms.
5. The electronic warp stop motion and weft stop motion on these
looms give a fault free fabric.
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6. The system is less expensive and easy to maintain and saves time
in the production.
JACQUARD LOOM
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INTRODUCTION TO JACQUARD
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Decorated fabrics can only be woven by a loom that allows the raising and lowering of individual warp threads to permit the different coloured weft threads to be inserted by the shuttle in such a way that a design can be created in the fabric.
The first loom that made it possible to create a pattern in fabric was called a drawloom. The first draw loom was invented in China in or around the 2nd century BC. This loom allowed the warp threads to be drawn up individually to create a design to be woven. But it was maddeningly slow and search for a more user-friendly loom that could weave intricate designs only ended with invention of jacquard loom.
The Jacquard Loom is a mechanical loom, invented by Joseph Marie Jacquard. The Jacquard Loom is a mechanical loom, invented by Joseph Marie Jacquard in 1804, that simplifies the process of manufacturing textiles with complex patterns such as brocade, damask, and matelasse. The loom is controlled by punch cards with punched holes, each row of which corresponds to one row of the design. Multiple rows of holes are punched on each card and the many cards that compose the design of the textile are strung together in order. It is based on earlier inventions by the Frenchmen Basile Bouchon (1725), Jean Falcon (1728) and Jacques Vaucanson(1740).
On seeing Jacquard's punched card system, the mathematician Charles Babbage was inspired to use the same principles to design a mechanical calculating machine, the forerunner of modern computers, that he called the “Analytical Engine”. He himself wrote,
“The system of cards which Jacquard invented is means by which we can communicate to a very ordinary loom orders to weave any pattern that may be desired. Availing myself of the same beautiful invention I have by similar means communicated to my Calculating Engine orders to calculate any formula however complicated.”
200 years later, the inventions of Jacquard and Babbage led the world to the modern day computer which, among an almost infinite and growing number of uses, guides the jacquard loom in reproducing tapestries of exquisite detail.
HISTORY
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In consequence of the Industrial Revolution, the late 18th century had witnessed a
considerable expansion in the automation of processes that had once been the
preserve of small groups of highly skilled workers employed in so-called ‘cottage
industries'. The textile industry was one sphere were industrialization had rendered
obsolete such skills. Whereas, prior to the development of mechanical looms and
weaving machines, lengths of fabric had to be woven slowly by hand, the advent of
powered tools for carrying out this task meant that quantities of fabric could be mass-
produced at a far quicker rate than previously, thereby reducing its expense. There
was one area, however, where the new machines could not compete with skilled
manual workers, adding designs to fabric.
In 1804, however, everything changed. Jacquard unveiled the loom that now bears
his name. Joseph Marie Jacquard, a weaver of silk, invented the Jacquard loom,
which made use of punch cards in order to improve the functionality of the textile
loom. The Jacquard Loom provided a solution to this problem so that, with it in use,
extremely intricate patterns and pictures could be automatically woven into cloth at
much the same rate as a plain length of fabric could be generated. The jacquard
loom incorporated ideas from other, experimental looms, but in a way that created a
uniquely practical machine.
Like jacquard’s earlier loom, the jacquard loom could be operated without the help of
a draw boy, because a mechanical device that could lift the warp threads had been
added. Perhaps the most innovative feature of the jacquard loom, however, was that
it could be ‘programmed’ to create any desired design by using punch cards. A
punch card is a small card made of thick paper with a pattern of holes.
The punch- card system endowed the loom with flexibility; the punch cards could be arranged to create a repeating pattern or to weave one large design. Unlike Jacquard’s earlier loom, this loom had no limitations on the type of design that could be automatically woven. In addition, if a weaver wanted to use an identical design in other tapestry; the cards for that design could be reused. Since the jacquard loom
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lifted the correct threads automatically, the process of weaving designs became much faster. Earlier weaving designs into silk was an extremely time-consuming process and silk weavers often could not begin to meet the demand for the demand for their products. A skilled weaver and draw boy using the best equipment available used to produce only about an inch (2.54cm) of desired silk cloth a day. A weaver using a Jacquard loom could weave up to two feet (0.6m) of fabric each day, in any design imaginable, and all without the help of a draw boy. Jacquard’s loom astonished his contemporaries, and jacquard himself received enormous praise. In 1805, Napoleon decreed Jacquard’s loom public property, guaranteeing its inventor a lavish annual pension from the French government and a generous royalty for every jacquard loom brought into use.
Joseph Marie Jacquard's invention was fiercely opposed by the silk-weavers, who feared that its introduction, owing to the saving of labor, would deprive them of their livelihood. In fact, the introduction of these looms caused the riots against the replacement of people by machines in the second half of the 18th century.
However, its advantages secured its general adoption, and by 1812 there were 11,000 automated looms in use in France. The Jacquard loom was declared public property in 1806, and Jacquard was rewarded with a pension and a royalty on each machine. The looms allowed French weavers to make much larger, more elaborate designs than had been practical with previous looms. The result was a boon in the French textile industry and a sharp increase in demand for French fabrics abroad. France tried to maintain the advantage by keeping the new technology secret, but details of the Jacquard loom eventually leaked-out. By the 1830s, Jacquard looms were in use in other European countries, including Great Britain.
Jacquard continued making improvements to his loom. In 1819, he received the Cross of the Legion of Honour; one of France’s most prestigious awards. In the 1820s, Jacquard retired to the village of Oullins, where he died in 1834.
Jacquard looms are still in use, and the word jacquard is now a common noun meaning a fabric with an elaborate weave or pattern. Modern Jacquard looms are powered by electricity, and computers are used to develop the designs, but the basic process remains unchanged.
For inventing such a labor saving device, Joseph Jacquard should be applauded. His invention let weavers continue to make beautiful tapestries, but at a price that could be afforded by a greater portion of the population. These lower prices are letting the average person be able to display these fine works in their homes and enjoy something once reserved for only the rich.
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“The portrait of Jacquard was, in fact, a sheet of woven silk, framed and glazed, but looking so perfectly like an engraving that it has been mistaken for such by two members of the Royal Academy.”
Charles Babbage
The portrait deliberately designed to illustrate and show off the Jacquard loom’s capabilities, is so complex it contains 24000 rows of weaving. Every single row was controlled by a 19th century programming device – punching cards. These punched cards lie at the heart of Jacquard’s brilliant concept of an automatic loom that weaves complex patterns and images. The dimension of this is 20 x 14 inch. It is now preserved at Science Museum in London although unfortunately the portrait is no longer on general display.
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Jacquard introducing Napoleon to his newly-invented loom.
A Jacquard Loom workshop - Germany, 1858
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JACQUARD SHEDDING MECHANISM
A decorative woven or knitted pattern manufactured by using the Jacquard
attachment on the loom. This attachment has a punch card like a piano, so it offers
better design versatility and fabric control. In this shedding the warp ends are
controlled individually by harness cords. There will ne as many cords as there are
ends in the warp. There are no heald frames. Because the warp ends are controlled
individually by the shedding mechanism, the patterning possibilities are virtually
limited. Some types of jacquard fabrics have specific names, like damask and
brocade. Used in a variety of apparel, like our Holdup Suspenders and home goods
form drapes to upholstery.
The Jacquard Loom consists of two main parts:
1. Loom
2. Jacquard
The loom is bolted to the flooring and the jacquard is suspended from the ceiling
resting on heavy beams. The two are connected by a series of cords known as
Harness.
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PRINCIPLE PARTS OF THE JACQUARD MACHINE
A jacquard machine consists of three different parts:
(1) An engine i.e. shedding motion
(2) Harness, and
(3) A mechanism which connects the engine to the loom
ENGINE
This part of the machine contains the mechanism by which the warp threads are
selected and lifted to form the top shed line. Main parts of the engine are
Needles
Needle board
Spring box
Hooks
Griffe
Cylinder
Card Cradle
a. Needles
The needles rest with their heads in the needle-board, the needles extending outside
the needle board towards the cylinder by about 4 mm. The rear part of the needle - a
loop - passes in the spring-box. In a single lift jacquard, a needle carries at its rear
end small light helical spring contained in the spring-box. The needles are constantly
pushed towards the cylinder by these springs. If the needles are not pushed
backwards towards the spring-box, the upper crooks of the hooks will remain in the
position, over the griffe-bar and raising the latter will raise every one of these hooks;
but when the heads of the needles are pushed backwards, the hooks are also
moved out of the way of the rising griffe-bars, thus causing an empty lift when they
are raised.
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b. Needle-board
It is a wooden board perforated with holes corresponding to the number of needles
and it serves as a guide for the needles to be presented to the cylinder.
c. Spring- box
The rear part of the needle, a loop, is passed in the spring-box and the loop permits
a flat wire or a pin to be inserted which holds the needle in position. One pin is
required for each vertical row of the needles. A brass spiral spring is securely held
on one end by the wider part of the loop and on the other end by the pin inserted in
the loop. Pressing the needle at the head compresses the spring and removal of the
pressure at the head of the needle will bring the spring to its natural position, pushing
the needle to its original place.
d. Hooks
The vertical wires are turned over at the top to from a hook for which reason they are
called hooks of the jacquards machine. The top portion of the hook in its upright
position is over the griffe-bar or knife. As the hook passes through the bent portion of
the needle, it can be taken away from the knife if the needle is pressed back. The
hooks are doubled at the base and turned upwards for about one third of their
lengths. This double end is passed through a narrow slot in the grate. The end of the
double wire also forms a hook which normally rests on the semicircular ribs. The
double wire portion combined with the cross wire in the grate effectively prevents the
hook from twisting around. At the bottom portion of the double wire of the hook, short
but strong cords known as neck cords are looped and are subsequently passed
through the perforations of the tug board. Thus when a hook is raised a neck cord is
also lifted up along with it. In a single lift jacquard, there are as many hooks as the
number of hooks to that of the needles.
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e. Griffe
The knives are made of strong hoop iron and these horizontal knives (or griffe-bars)
are contained in the iron frame called the griffe on head. The griffe with the knives is
operated to rise and fall in a vertical plane. There are as many knives in a jacquard
as there are hooks in the short row. Every knife is fitted close to the hook but is
not allowed to press against them. The sides of the knives facing the hooks are
leveled off. This is to avoid the striking the top of the hooks are made to occupy
such a position that they will be caught by the knives, the hooks and
consequently the harness lines are lifted up when the griffe moves up.
f. Cylinder
The perforated cards are laced to form and endless chain over, a four sided
wooden prism called a cylinder. (Though called a cylinder, it is not circular in its
cross-section). It is made of very hard and well seasoned wood to prevent any
tendency to subsequent warping in the humid atmosphere of the weaving
department. Each face of the cylinder is perforated to correspond with the
number and arrangement of the needles in the machine. The tapering wooden
pegs are driven into every face, midway between the cylinder edges. These
pegs help in drawing forward and holding each card in turn, with its holes over
those in the cylinder.
The function of the card cylinder is to present on jacquard cards to the needles,
one at a time. A metal supporting end called lantern is fixed on each end of the
cylinder. The cylinder is supported by gudgeons, their bearings being in a frame
that moves horizontally. The cylinder is given two types of motions:
i. to-and fro motion
ii. rotary motion to the extent of one fourth revolution
Resting on the lantern of the cylinder is an inverted T-shaped hammer. A strong
spiral spring keeps the hammer in contact with the iron part of the cylinder.
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g. Card Cradle
When a large number of cards are to be worked on the machine, the entire
weight of the cards will have to be borne by the Jacquard machine. A long
endless chain of cards suspended above will also obstruct the working and
vision of the loom parts. It is also necessary to keep the bulk of the cards in a
convenient position so that they may be taken up by the cylinder in a proper
sequence. In order to achieve all these functions, a card-cradle is provided
below the iron on steel girders on which the jacquard machine is mounted.
Wires, slightly longer than the length of the cards are attached to the set of cards
at regular intervals of say 12, 16, 20 or 24 cards. A card cradle consists of two
curved iron rods kept at a distance slightly in excess of the length of the cards.
When the attached wire reaches these curved rods, its ends rest on them
thereby supporting the cards.
MECHANISM WHICH CONNECTS THE ENGINE TO THE LOOM
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A jacquard is installed on a support over the loom in many ways. The support is
known as gantry. It is made of steel or wooden beams carried on columns resting on
the ground or hung from the ceiling. The best height for a jacquard is generally
decided by the width of the warp in the reed.
Jacquard is usually driven from the loom shaft by means of rods and levers. Modern
driving motions are either by steel roller chains with machine cut wheels or by a
vertical revolving shaft with a bevel and bevel wheel drive.
In jacquard shedding two drives are essential:
(1) To drive the griffe in a vertical plane so as to operate the hooks and
(2) To drive the cylinder.
The cylinder in its turn needs two types of drives:
a. Cylinder with its cards facing the needle board should move towards the
needles to accomplish the selection is over, the cylinder should move away from the
needle board so that it should be turned through a quarter turn to present another
card when it moves into the needle board next time. This is to-and-fro motion of the
cylinder.
b. When the cylinder moves out, it should get a quarter turn, as mentioned
above to present the next card in the series. This is a rotary motion of the cylinder.
There are many ways in which the above motions and drives are obtained which
one can easily study on machine with which he has to work.
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CONVENTIONAL MECHANISMS
Jacquards are devices that help form the warp shed in the desired manner. They
consist of two parts, namely a selection device for choosing which warp threads are
to go up and which are to remain down, a lifting mechanism to lift the warp that has
to be raised.
Lifting mechanism
Warp pass through the eyes in the heald cords instead of the heald wires as in the
case of frame shedding. Warp threads are divided into groups that are connected to
hooks resting above them by a system of harnesses that are guided by the comber
board. The knives constantly move up and down and lift the hooks that are resting
on them. If a particular hook is required to stay down, (i.e. the warp threads are
supposed to stay down), then it is made to disengage from the knife. When the knife
goes up, tile selected hook stays down while the others go up.
Selection device
The selection of the hook is done by a mechanism that is preprogrammed to control
the hooks according to the design. The design program is in the form of a card in
which holes have been punched. Each card represents an individual pick while each
hole on the card (or the space where tile hole could be but is not) controls an
individual group of ends. A chain of cards, with holes punched in them, is used as
required. The number of cards in the chain is equal to tile number of picks in the
length of the repeat of the design along the warp. The chain of cards moves on a
quadrangular cylinder that rotates to present a new card to the needles after every
pick. The needles are perpendicular to the hooks and loop around them. When a
needle moves horizontally, the hook catches in the loop and bends away from the
knife. The needles are arranged in such a way that they are aligned with holes (or
the places where the holes could have been) in the card. The cylinder on which the
chain of cards moves can also oscillate horizontally back and forth. This is done to
facilitate the rotational movement of the cylinder.
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FUNCTION
Most of the fabrics are used for domestic and industrial purposes, but some of the
fabrics have decorative uses. A fabric may be ornamented by:
Embroidering
Printing
Figured weaving
In the first two cases the fabric is first manufactured and ornamentation is done
subsequently but in the case of figured weaving the cloth is ornamented
simultaneously with its production. Dobbies and jacquard shedding are employed.
The expression jacquard loom which is frequently used is a misnomer since the term
jacquard implies to shedding mechanism only which can be mounted on any loom by
making a few alterations. There is no heald-shaft harness as used in dobby or tappet
shedding mechanism but instead a thread harness is used.
Jacquard weave is used to produce patterned fabrics. The intricate patterns or figures are created all over the fabrics. Fabrics of jacquard weave are costly because it involves more time and skill in making the Jacquard cards to produce new pattern. Moreover the weaving operation is also very slow.
Characteristics of Jacquard Weave The fabrics have the tendency to have floats. It has luster contrasts.
It has snagging potential.
It is more stable and resilient than the basic weaves.
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All fancy or figured fabrics such as
Silk
Cotton brocades
Damasks
Brocatelle
Matelasse
Toilet quilts
Extra-warp or extra-welt figured fabrics
Figured equal or unequal double cloths
Madras muslin
Swivel fabrics
Leno brocades
Tapestries
Portraits
Animals
Geometrical figures
Landscapes
The above fabrics require the jacquard shedding mechanism to weave them on the
loom. A number of weaves may be used in combination to produce a Jacquard
design with the desired effects. Jacquard weaving is, however, an expensive form of
weaving as it is accompanied with designing, card cutting, lacing and all other jobs
associated with. The speed of the loom with jacquard shedding mechanism is also
lower than that of a similar loom with dobby or tappet shedding.
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CLASSIFICATION OF JACQUARD
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The Ordinary Mechanical Jacquard can be classified on three basis, viz:
I. Types of shed:
1. Bottom closed shed
2. Centre closed shed
3. Open shed
4. Semi-open shed
II. Number of griffe:
1. Single-
a. Single lift single cylinder
2. Double-
a. Double lift single cylinder
b. Double lift double cylinder
III. Pitch:
The Special Mechanical Jacquards are of many types. Some of them are:
Cross-border Jacquard
Self-twilling Jacquard
Plain Double Cloth Jacquard
Leno Jacquard
Split Harness Jacquard
Pressure Harness Jacquard
Marseilles Quilt Harness Jacquard
Mitchelline Quilt Harness Jacquard
The Electronic Jacquards are of three kinds; viz:
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1. Grossee
2. Bonus
3. Staubli
Comparison Between Slsc, Dlsc And Dldc
BASIS SLSC DLSC DLDC
No. Of lifting agents
There is a single lifting agents
There are two lifting agents
There are two lifting agents
No. Of cylinders
There is a single cylinder.
There is a single cylinder.
There are two cylinders.
Ends controlled by
Each end is controlled by single hook.
Each end is controlled by two hooks.
Each end is controlled by to hooks.
Type of shed
Bottom closed shed is formed
Semi open shed is formed
Semi open shed is formed
Drive to griffe
Drive to griffe from crank shaft
Drive to griffe from bottom shaft
Drive to griffe from crank shaft with the help of common shaft
BASIS SLSC DLSC DLDC
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Drive to cylinder
Drive to cylinder from crank shaft
Drive to cylinder from crank shaft
Drive to cylinder from crank shaft with the help of a common shaft
Beating up
Beating up is done in closed shed so firm beat up is not possible.
Beating up is done in crossed shed so firm beat up is possible.
Beating up is done in cross shed so firm beat up is possible.
Use
Usually used in delicate weaving
Used in ordinary weaving forms of cotton weaving
Used in cotton and heavy weaving industry
SLSC-Single lift single cylinder
DLSC-Double lift single cylinder
DLDC-Double lift double cylinder
JACQUARD WEAVING IN INDIA
The Jacquard loom was introduced in India under the British and soon became the preferred choice of weavers as they could create complex designs with much less labour. It also reduced the cost of cloth and brought it within the reach of the lower classes. Today, the Jacquard loom is used in various parts of India. The main centres are Delhi, Jaipur, Varanasi, Kanchi, Kolkata, and Mangalore where cloth for products like tapestry, upholstery, saris, shawls, scarves and other apparels are produced.
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PROBLEMS
1. Effort
When the warp warps are in their natural position, that is, in a straight line between
the warp beam and the cloth roller, they are said to be in the centre shed position.
When they have moved to the top position they are said to be in the top shed and
when they are in the bottom position they are said to be in bottom shed.
In the centre shed the warp are in the least motion. Because they are distorted out of
their straight line in both the top and the bottom shed, the tension in the warp
increases with a tendency for them to revert to the centre shed.
In a jacquard the normal position for a warp is the bottom shed. The warps are
normally distorted in the bottom shed position. When a shed is formed, the warps
that are supposed to be above during that pick go up while the other warps remain
down. This means that a jacquard is a negative mechanism, that is, it can move the
warps in just one direction. It can only raise the threads which then come down
owing to gravity.
Because the warps in the normal bottom shed are distorted out of shape, the tension
in them tries to pull them up. It is very important for them to remain in a clean bottom
shed line. If the warps are not at the same level, the shuttle flying over them will get
caught in them and break them. To keep the warp threads down in the bottom shed,
a downward force has to be applied to keep them down. In existing jacquards this is
done with the help of lingoes which are lengths of wires with a specific weight. These
lingoes hang from the eye harness, keeping the warp in the bottom shed position.
With the warp groups, the corresponding lingoes also have to be lifted up. The
weight of these lingoes adds up, as usually a couple of thousand odd threads are
worked upon. For example, if 2000 warps are being used and 12 grams of lingoes
are hanging from each eye harness and if half of the warps have to go up (as in the
case of a plain weave), then a dead weight of 12 kg has to be lifted. The problem is
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severe in case of very complicated designs when weights close to 40-50 kg need to
be lifted.
2. Height
The conventional jacquards are very tall mechanisms for which either a special work
shed is required or weaving is done in the open.
This problem occurs because of the geometry of the harness that connects the
hooks to the heald cords, with the warp running through their corresponding eyes.
The warp threads that are not directly below the hook, to which they are attached,
rise up less than the one that is directly below. In fact the warp threads further away
from the one directly below the hook, rise successively less and less. The problem
becomes very pronounced in jacquards of big widths. The shed opening towards the
side ends of the loom gets progressively smaller and results in the shuttle rubbing on
the thread.
The height of a conventional jacquard is dependent on the harness which has to be
long in order to minimize this problem.
3. Complexity and cost
The existing jacquards are very heavy and complicated mechanisms. The selection
device does not directly act on the hooks, but through an interface, that is the
needless.
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ADVANTAGES AND DISADVANTAGES OF JACQUARD LOOM
ADVANTAGES
1. Can produce fabrics up to 600 epi or ppi.
2. Helps in constructing intricate design which are otherwise impossible by
dobby and tappet shedding mechanisms
3. Due to presence of cards, weaving of complex designs becomes possible. It is
a more simple method of feeding the design to the loom to weave.
4. Have lingoes for maintaining tension in the warp threads
5. Possible to control every warp yarn individually
6. As there are different cylinders for even and odd picks, each cylinder has to
turn one quarter in every two picks.
7. With the help of the casting out process, it is desirable to omit whole rows of
hooks if not required. This simplifies the designing and card-cutting process.
DISADVANTAGES
1. This mechanism contains more moving parts
2. Initial cost is very high
3. Maintenance cost is also high
4. Can produce design faults in fabric
5. Preparing a design and cutting pattern cards requires skilled labor
6. Limitations on the speed of the loom due to complex mechanism
7. The loom becomes very large
8. There is a lot of wear and tear of the parts: hooks, needles, springs
9. Generates semi-open shed, in which there is unnecessary movement of warp
threads to the bottom shed line
10. Less efficient as manual operation
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11. The link transfer between the hooks occurs at the highest speed of these
hooks, this result in the jerky performance of the harness cords which may result in
‘lashing’.
Advancements In Jacquard Looms
Since it takes a long time to produce a point-paper design (approx. two
hundred hours for one design), the computer can scan the pattern very rapidly and,
by means of a program, convert the warp and filling interlacing into a binary number
form that can be ‘read’ by the computer. The changes in the design can be made by
using light sonic pen.
The advantages of this system over regular jacquard looms are:
Computer systems may be too expensive; however, automation shortens the
lead time between the design concept and the production of a sample.
More than one version of a design can be made so there is more opportunity
for experimentation in the designing process.
Fast sampling may be economical because styling approval can be given
quickly.
Manual card cutting is eliminated, for sampling as well as for large-scale
production.
No need for special personnel training and thus, paying competitive wages for
jacquard card cutting.
The magnetic tape required for making the final design can be stored in the
computer for future use.
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REFERENCES
WEBSITES:
www.texmin.nic.in www.indiantextilejournal.com www.indianmba.com www.baharttextile.com www.fabric-manufacturers.com www.ecvv.com www.housefabric.com
BOOKS:
Handbook of Cotton Weaving, by M.I.R. Publishers
Mechanism of Weaving, by Thomas. W. Fox
Fancy Weaving Mechanisms
Handbook of Weaving: Jacquard, by Puneet Kishore
Principles of Weaving, by K.T. Ashwani
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