Rapier weft insertion system

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Rapier Weaving
A rapier loom is a shuttleless weaving loom in which the filling yarn is carried through the
shed of warp yarns to the other side of the loom by finger-like carriers called rapiers.
Mr. John Gabler can be regarded as the father of modern rapier technology he has built a
rapier device on a cotton weaving machine in 1922. Later in 1939, Remond Dewas
introduce the dewas rapier filling insertion system (tip to tip weft transfer).
In rapier weaving, a flexible or rigid solid element which is called rapier is used to insert
the filling yarn across the shed. The rapier head picks up the filling yarn and carries it
through the shed. After reaching the destination, the rapier head returns empty to pick up
the next filling yarn, which completes a cycle. A rapier performs a reciprocating motion.
Rapier weaving machines are known for their reliability, performance and versatility which
is able to weave a wide range of fabrics.
Features of Rapier Loom:
Rapier weaving machines are known for their reliability and performance. Since 1972, the
rapier weaving machine has evolved into a successful, versatile and flexible weaving
machine. Common feature of rapier weaving machines are:
 A very wide range of fabrics can be woven on a rapier weaving machine which is
typically from very light fabrics with 20 GSM to heavy fabrics with around 850
GSM.
 Rapier machines are widely used for household textiles and industrial fabrics.
 Designed for universal use, the rapier weaving machine can weave not only the
classic wool, cotton and man-made fibers, but also the most technically demanding
filament yarns, finest silk and fancy yarns.
 Lightweight grippers with a balanced center of gravity, tape bracings and extended
tape guides, combined with support teeth in the lower shed, provide smooth, yarn
friendly gripper run.
 In the latest machines, the rapiers are made of composite materials and the rapier
guide is eliminated. As a result, there is no contact of the warp yarns with the metallic
rapier guide. Since there is no friction with the rapier guide, the stress on the tape
and rapier assembly is reduced.
Advantages of Rapier:
 Impart minimal stress on the filling yarn.
 Up to 16 different filling yarns can be inserted.
 The gripper heads take a wide range of yarn counts ranging from 5 to 1000 tex.
 Modern rapier machines have the weft insertion rate up to 1400 m/min.
 With the rapier system, insertion of double picks is possible.
 Low yarn breakage rate.
 Rapier machines can have up-to 28 harnesses.

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Disadvantages of Rapier:
 Half of their movement is wasted.
 Warp thread can be damaged by the ribbed guide in case of flexible rapier.
 Noise level is higher than jet loom.
 Production speed is less compared to jet or projectile loom.
 Rigid rapier require larger space.
Types of Rapier:
Rigid Rapier:
The rigid rapier is a metal or composite bar usually with a circular or rectangular cross
section attached with the rapier head.
Advantages:
 They do not require guiding across the warp sheet, the rapier head slides on the
warp or on the race-board.
 High mass and rigid construction ensures straight movement of rapier heads.
 A great diversity for both warp and weft threads in yarn count and character.
Disadvantages:
 Large floor space requirement, at least twice the fabric width.
 Half of their movement is wasted (common to all types).
Flexible Rapier:
The flexible rapier has a tape-like structure and can be coiled when it is withdrawn from
the warp shed and this saves considerable space. Long flexible blade tends to buckle when
violently accelerated from the rear and to prevent it, guides are required. Ribbed guide
require for the correct movement of the rapier. Ribbed guide lies between warp ends when
the shed is open. The guide pass under the cloth fell when the sley approaches its most
forward position. Close but contactless high precision positioning of the rapier head close
Rapier
Rigid
Single
Double
Dewas
Gabler
Flexible
Single
Double
Dewas
GablerTelescopic

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to the reed results in clean shed separation, even with clinging warp ends and a small shed
opening angle.
Advantages:
 Less floor space requirement, spatial productivity is higher.
 Flexible rapier band are wound on wheels or placed in n semi-circular channels
when they are withdrawn outside the shed, and the result is wide working widths up
to 5 m.
Disadvantages:
 The warp threads can be damaged by the ribbed guides.
 Using fancy yarns in warp direction is almost impossible.
 Guiding system may lead to the end breakages due to knot failure.
 By eliminating guides, there is the advantage of reducing end-breaks due to knot
failure and the weaving of fancy yarns becomes much easier because the
obstructions are removed from the warp shed.
 Wasted movement.
Telescopic Rapier:
The disadvantage of the large floor space requirements of rigid rapiers is removed on
weaving machines equipped with telescopic rapiers. Space can be saved on this type of
rapier drive if a compound rapier operating on the principle of telescopic expansion is used.
Single Rapier System:
In the single rapier, rapier enters the shed from
one side, picks up the tip of the filling yarn on
the other side and passes it across the weaving
machine while retracting.
Advantages:
No need of weft transfer from rapier to rapier
at the center of the loom. For that it is suitable
for filling yarns which are difficult to control.
Disadvantages:
 A single rapier carries the yarn in one
way only and half of the rapier
movement is wasted.
 The length of the single rapier is equal
to the width of the loom, this requires
relatively high mass and rigidity of the
rapier to ensure straight movement of
the rapier head.
 When a rigid rapier is used, the space required by the loom must beat least double
that of the reed space to allow the rapier to be withdrawn from the shed.
Figure: Single rapier weft insertion
system.

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Double Rapier System:
Two rapiers are used in this system. One rapier called the giver, takes the filling yarn from
the yarn accumulator on one side of the weaving machine, brings it to the center of the
machine and transfers it to the second rapier which is called the taker. The taker retracts
and brings the filling yarn to the other side. Similar to the single rapier machines only half
of the rapier movements is used for filling insertion. Double rapier machine can be rigid or
flexible and the double flexible machine are most common than the rigid rapier machine.
There are two types of double rapiers: Dewas system (tip to tip weft insertion) and Gabler
system (weft insertion in the form of hairpin).
Dewas System:
In Dewas system, the giver grips the tip of the yarn, brings it to the center and transfers it
to the taker which retracts and carries the yarn to the other side of the weaving machine.
There is a possibility of dropping the weft yarn during transfer.
Gabler System:
In the Gabler system, the yarn is not gripped. The giver extends the yarn in the form of a
“U” shape to the center of the weaving machine. The yarn is then transferred to the taker,
Figure: Schematic of Dewas System
(tip transfer).
Figure: Schematic of Gabler System
(loop transfer).

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which extends the yarn to the other side of the weaving machine by straightening it. As
the weft is not gripped by the rapier head, the possibility of dropped weft on transfer at
the rapier heads in the middle of the loom is eliminated.
Dewas Gripper:
The gripping unit usually consists of a fixed point against which a spring-loaded clamp
presses to trap the weft. These points open the clamps when the weft is to be picked up or
released outside the selvedge. The right-hand head (Giver) traps the weft at A and pulls it
through the shed until the rapiers meet. The thread is then guided round the point B and
when the left-hand head (Taker) withdraws, the thread is trapped at C and pulled across the
loom to complete insertion.
Gabler Gripper:
The weft is never gripped. As the cut-out A at right-hand head (Giver) of the rapier
advances towards the center of the loom, the yarn passes from its clamped position, round
the rapier head, to the supply package in the form of a hairpin. When the two rapier heads

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meet at the center of the loom, the left-hand head (Receiver) enters the yarn carrying right
hand head. The thread at A is passed under the spring-loaded cover guide at B and as the
left –hand rapier is withdrawn, it reposition the weft at C. Then the yarn can slide through
the left-hand rapier head and it is withdrawn so that the hairpin is straightened out.
Heads of Gabler system cause the weft yarn to vigorous abrasive strain both during
insertion of loop into the center of shed as well as during unfolding of loop over the other
half of the warp shed.
Rigid rapier v/s flexible rapier
Rigid Rapier Flexible Rapier
No need of ribbed guide. Require ribbed guide.
Require more space. Require less space.
Low stress on warp yarn as there is no
guide.
Friction of warp yarn with ribbed guide.
Fancy yarn can be used in warp direction. Using of fancy yarn in warp direction is
almost impossible.
Lower possibility of end breakages as no
guide is used.
Guiding system may lead to the warp
breakages due to knot failure.
Diagram of rapier sequence in weft insertion
Figure: Rigid rapier sequence (tip to
tip transfer).
Figure: Flexible rapier sequence
(loop transfer).

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Rigid rapier (tip to tip transfer) sequence:
Time-1: Rapiers are in rest position and about to enter the shed on the first pick of
the insertion cycle. The weft is correctly positioned for gripping by the rapier.
Time-2: Both the rapiers have entered the warp shed. The end of weft is gripped by
the rapier and the rapier is drawing the weft from the supply package.
Time-3: The right hand and the left hand rapier are at their center position and the
weft yarn is transferred from the left hand rapier to the right hand rapier.
Time-4: The right hand rapier travel towards its initial position with the yarn and the
left hand rapier without the yarn.
Time-5: Now the first pick is fully inserted and the weft clamp is closed to supply
the weft from the package and the weft is cut by the cutter. Then the gripper release the
yarn and the beat-up is done. Then the whole cycle is again repeated.
Flexible rapier (loop transfer) sequence:
Time-1: Rapiers are in rest position and about to enter the shed on the first pick of
the insertion cycle. The weft is correctly positioned for the weft insertion.
Time-2: The weft are supplied from the package. Both the rapiers have entered the
warp shed. The left hand rapier gives the weft loop shape by hairpin type action.
Time-3: The right hand and the left hand rapier are at their center position and the
loop of weft yarn is about to be transferred from the left hand rapier to the right hand rapier.
The weft clamp is closed to supply of weft from the package.
Time-4: The right hand rapier travel towards its initial position with the loop of yarn
and the left hand rapier without the yarn. The right hand rapier extends the weft yarn to the
other side of the loom by straightening it.
Time-5: Now the first pick is fully inserted and the weft is cut by the cutter. After
that shed is change and the beat-up is done. Then the whole cycle is again repeated.

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Two phase weft insertion by Rapier:
In two phase weft insertion system, the rigid rapier is driven from the center and has a
rapier head at each end. In one cycle of 360°, the rapier inserts one pick alternately in the
right hand and the left hand fabrics, the picks being inserted and beaten up in opposite
phase. A creel (A) which carries packages is located in the center of the machine. The weft
yarn (B) is drawn off continuously under low tension by means of delivery rollers (C) from
the weft package and guide to the storage chamber (D) where it is stored in the form of a
loop by a suction device. As the yarns exit from the storage chamber the presenter (E)
presents the weft to the gripper (F) which inserts it through the shed to the outer fabric
selvedge. At this time, the supply of yarn stops from the storage chamber. When the dead
point at the end of the rapier travel path is reached, the weft yarn is taken over by the rapier
clamp (G) which moves simultaneously with the reed. While the rapier is moving to the
other side of the machine, the shed of the first phase fabric starts to close. After the first
weft insertion sequence is completed, the process is repeated for the other side of the
machine.
Figure: Two phase weft insertion system.

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Rapier guide:
Weft Feeder:
Weft feeder draws the weft yarn off cross-wound package and coils it on to accumulator
drum at a predetermined speed. When sufficient weft yarn supply has been wound on, weft
reserve monitor interrupts the coiling process until this weft yarn has been inserted. The
weft yarn is therefore always unwound from the same drum diameter at weft insertion and
thus maintains a defined weft tension. Brake ring prevents ballooning during drawing-off.
The weft yarn is tensioned by electromagnetic weft brake depending on the weft insertion
conditions. The weft brake responds to the commands entered at the terminal. Braking
force and timing can be adjusted individually. Monitoring device monitors the pick during
a defined insertion period.
Ribbed guide lies between warp ends when the shed
is open. The guide pass under the cloth fell when the
sley approaches its most forward position. Close but
contactless high precision positioning of the rapier
head close to the reed results in clean shed separation,
even with clinging warp ends and a small shed
opening angle.
1- Cross-wound package
2- Weft feeder unit
3- Feeder drum
4- Weft reserve monitor
5- Brake ring
6- Electromagnetic weft
brake
7- Monitoring device
Figure: Schematic of weft yarn supply and weft feeder unit.

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Color control:
Electronically controlled color selector with optimized filling yarn feeding unit allows
yarn-friendly filling insertion of up to eight colors. The pick sequence is determined by the
fabric style and is controlled electronically. The required pick sequence is stored in the
terminal. During pick finding, the color control is synchronized electronically, so that the
weave and the weft color always correspond. Magnet 2 of the required weft yarn is
activated, thus drawing tongue 3 to the magnet in the read-in position of carriage 4. The
carriage pushes the tongue forward and weft finger 1 lowers the weft yarn into the zone of
the left-hand gripper. If the same weft yarn is inserted several times in succession, the weft
finger remains in the insertion position (below).
Some rapier loom manufacturers:
 Dornier
 Somet
 Picanol
 Sulzer
 Vamatex
 Jacob Muller
1. How the low tenacity yarn breakage rate reduced in a rapier system?
Answer: Light weight grippers with a balanced center of gravity, tape bracings and
extended tape guides, combined with support teeth in the lower shed, provide smooth, yarn
friendly gripper run which provide an advantage of rapier machines is that they impart minimal
stress on the filling yarn. Minimal stress on the filling yarn during processing results in good
1- Weft finger
2- Magnet
3- Tongue
4- Carriage
Figure: Schematic of color control.

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fabric quality and high efficiency. The lower shed does not make contact with the gripper head.
The precise shed separation gives good warp run and low warp breakage as a result of optimum
warp tensioning.
2. What are the factors affecting the warp and filling stresses on a rapier machine?
Answer: The stress on the warp yarns is caused by the following:
 Initial set up stress.
 Shed formation
 Back rest roller movement
 Reed beat-up
The filling yarn stress increases with increasing machine speed. The yarn tension also increases
with an increases in yarn fineness.