Advanced weft systems

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  • Weaving process and advancement in weft insertion system*

  • Weaving processWeaving of any fabric is simply done by three main mechanisms.warp let-offssheddingPickingBeatingFabric take up

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  • The weaving process can be explained as :Firstly the warp yarn are let off by warp let-off mechanism Shed formation is there to separate the sheets of warp yarns into two sheets upper and bottom. Then a weft yarn is passed into the middle of the two sheets of warp yarn by means of any weft inserting media whether shuttle projectile or jet mechanism (air, water)After the picking completed beat up of weft yarn to the feel of cloth done by means of reed After wards fabric wounds on the cloth roller which is take up mechanism.

    Weaving process*

  • Advancement in weft insertion system

    Projectile weaving machineRapier weaving machineAir-jet weaving machineWater-jet weaving machineMultiphase weaving machine

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  • Projectile Weaving Machine

    The Projectile weaving machine introduced into market in 1952 by Sulzer as the first successful shuttle less weaving machine.Projectile machine uses a projectile equipped with a gripper to insert the filling yarn across the machine.The unique principle of this machine is that we can practically insert the any kind of yarn like cotton ,wool, filament yarn, poly propylene or even jute as well, this is because all the finer or coarser yarns are securely grip by a gripper and inserted by the projectile

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  • Projectile motionFig: Hitting of Projectile with torsion rod and picking lever*

    * hitting of Projectile with torsion rd and picking lever

  • The principle operationThe projectile draws the filing yarn into the shed.Energy requires for picking is build up by twisting a torsion rod.On release the rod immediately returns to initial position smoothly accelerating the projectile by means of a picking lever.The projectile slides through the shed in rake shape guide and braked into the receiving unit.Projectile is then conveyed into the original position by a transport device (belt) installed under the shed .

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  • Advantages of projectile weaving machineLow power consumption Reduced waste of filling insertion due to unique clean ,tucked in selvagesQuick warp and change styleEasy operation ,maintenance and low spare parts requirements More than one width of fabric woven at a time due to large machine width such as 33-540cmsEnergy savingDifferent designs and color sequences can be woven.

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  • Rapier weaving machine

    In this type of weaving, a flexible or rigid solid element, 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.

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  • Single RapierDouble RapierTYPES OF RAPIER WEAVING MACHINESFlexible RapierRigid RapierDewas systemGabler System*

  • Single rapier weaving machinesA single, rigid rapier is used in these machines.The rigid rapier is a metal or composite bar usually with a circular cross-section.The 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.

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  • Fig: Single rapier transfers the yarn in one way*

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  • A single rapier carries the yarn in one way only and half of the rapier movement is wasted.The single rapiers length is equal to the width of the weaving machine; this requires relatively high mass and rigidity of the rapier to ensure straight movement of the rapier head.For these reasons, single rapier machines are not popular. However, since there is no yarn transfer from rapier to rapier, they are suitable for filling yarns that are difficult to control.

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  • Double rapier weaving machinesTwo rapiers are used in these machines one rapier, is called the giver, takes the filling yarn from the yarn accumulator on one side of the weaving machine, brings it to the centre of the machine and transfers it to the second rapier which is called the taker.The taker withdraws 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.

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  • Double rapier machines can be rigid or flexible.Double rigid rapiers are further classified into two types: Dewas system and Gabler system.In Dewas system the giver grip the tip of the yarn, brings it to the centre and transfers it to the taker which retracts and carries the yarn to the other side of the weaving machine.

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  • In the Gabler system, the yarn is not gripped. The giver extends the yarn in the form of U shape to the centre of the weaving machine.The yarn is then transferred to the taker, which extends the yarn to the other side of the weaving machine by straightening it.since both rapiers extend to the out side of the weaving machine, the space requirement of the double rigid rapier machines is high.

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  • In flexible rapier machines the rapier has tape-like structure that can be wound on a drum.This saves space and allows narrower machine widths compared to the double rigid machines.The yarn is gripped both by giver and taker.Double flexible rapier machines are more common than the rigid rapier machines.

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  • Versatility of rapierRapier weaving machine produces top- quality fabrics from spun yarns such as cotton-wool, camel hair, silk, synthetic fibers and fancy yarns.Rapier weaving machine are fast and exceptionally flexible.It offers a choice of various reed widths, shedding motions, selvedges and filling insertion colors. This makes it suitable for weaving an extended range of articles: fashion fabrics, shirting, denim, suiting, industrial or furnishing fabrics, in one to eight or twelve filling colors or yarns, with a maximum weight of 500 g/m2.

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  • Versatility of rapierToday's rapier weaving machine is designed with modern electronics, with total automation of weaving and central microprocessor control system, also ensuring maximum reliability, amazing user-friendliness, ease-of-operation, shorter style changing time, excellent fabric quality, low energy consumption.

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  • Water jet weaving machineThe water-jet weaving machines inserts the filling yarn by highly pressurized water.The tractive force (pulling force) is provided by the relative velocity between the filling yarn and water jet.if there is no velocity difference between the water and yarn then there would be no tension on the yarn which would be result in curling and snarling of the yarn.The tractive force is affected by the viscosity of the water and roughness and length of the filling yarn; higher viscosities cause higher retractive forces.The viscosity of water depends on the temperature.

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  • Water jet weaving machineWater jet weaving machines have the same basic functions of any other type of weaving machines.the principle of weft insertion with a water jet is similar to the filling insertion with an air jet: they both use a fluid to carry the yarn.however there are some differences has affect the performance and acceptance of water jet weaving machines.For example, the yarn must be wettable in order to develop enough tractive force.

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  • Water jet weaving machineThe flow of water has three phases:Acceleration inside the pump prior to injection into the nozzle.Jet out let from the nozzleFlow inside the shed. The water flow inside the shape has conical shape with three regions; Compact, split and atomized. Compact and split portions are better for yarn insertion. due to water weight the jets axis forms a parabola which necessitates adjusting the axis of the nozzle upward by some angle. the flow of water then flows the motion of angular projection.

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  • Water jet weaving machineThe width of the water-jet weaving machine depends on the water pressure and diameter of the Jet.Since water is not compressible it is relatively easy to give enough pressure to water-jet for insertion.The diameter of Jet is around 0.1 cm and the amount of water used for one pick is less than 2 cc.Double pump system, with two nozzle at will filling insertion, is suitable for weaving fabrics with two different fillings.

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  • Air- Jet weaving machineAir-jet weaving machine is a type of weaving in which a filling yarn is inserted into the warp shed with compressed air.Yarn is drawn from a filling supply package by the filling feeder and each pick is measured for the filling insertion by means of a stopper, the filling is feed into the feed tunnel via tandem and main nozzles.The tandem and main nozzle combination provides the initial acceleration, where the relay nozzles provide the higher air velocity across the weave shed.Profiled reed provides the guidance for the air and separates the filling yarn from the warp.

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  • Air- Jet weaving machineA cutter is used to cut the yarn when the insertion is completed.The air-jet weaving machine combines high performance with low manufacturing requirements.It has an extremely high insertion rate, due to its exceptional performance.Air-jet weaving machines are used primarily for the economical production of standard fabrics, covering a wide range of styles.Meanwhile, more and more special fabric segments are covered: heavy cotton fabrics such as denim, terry fabrics, glass fabrics, tire cord, etc.

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  • Principle operation of air jet weft insertion system Profiled reed*

    *Principle operation of air jet weft insertion system