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PRINCIPLES OF YARN CLEARING /YARN CLEARING IN WINDING / ASSESSMENTS OF CLEARER PERFORMANCE

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Objective of yarn clearing -     Objective of yarn clearing is to remove objectionable faults from the yarn / supply package Principles of measurement of yarn faults/Yarn diameter    Two principles are used in morden winders for identification of yarn faults   1. Capacitance principle    2.Optical principle  1.Capacitance principle - Working Principle- :    When yarn pass through two capacitor parallel plate the electrical signal changes / produce which is proportional to change in mass per unit length.  Capacitance (C) = εA /d                                 C= charge/Voltage Working -:       In the capacitor electronic yarn clear device is measurement of yarn mass per given test length        Any change in mass of yarn then the set value to makes corresponding change in a capacitance. The signal is send to the amplifier.  The amplifier amplifies the signal and compared with previously set value in the discriminator . If the limit is goes above the set v
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WINDING PROCESS

Object of Winding - 1. Conversion of small package into the bigger package (Ring bobbin into Cheese or cone having more yarn content than ring bobbin ) 2. To provide the long continuous length of yarn in the form of cheese and cone. 3. To remove the objectionable fault in the yarn ( Objectionable faults in the yarn which is allow to the yarn,we reduce the fabric quality and or reduce machine productivity) 4. To prepare the compact package cheese or cone which we have uniform density throughout the package and unwind well in the next process. BASIC PRINCIPLE OF PACKAGE WINDING    For package winding yarn can be withdrawn by two method 1. Side withdrawal 2. Over end and all nose withdrawal      In the side withdrawal for unwinding the yarn,package is rotated.    In nose unwinding package is stationary when there is nose unwinding one coil come out one twist either added or subtracted from the yarn depending on twist in the yarn . DIFFERENT TYPES OF WOUND PACKAGE 1.
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Jet Weaving Machines

Jet Weav ing Machine -             In this machines, weft yarn fed through the main nozzle is transported through the warp shed by the momentum imparted to it by jet of air or water blasting out of the nozzle . Functional El ements of Jet looms - - Weft feeding devices - weft accumulator , tensioners and stopper. - Main nozzle - Air guides and relay nozzles (only for air jet loom) - Suction funnel for air jet looms and water collecting arrangement for water jet looms. - Weft feeler - Air distribution       Unlike in case of other shuttleless weaving machines, the length of the weft yarn to be inserted need to be measured accurately in each weft insertion cycle in jet weaving machines , because of the lack of physical control over it is not weft insertion process. Basically ,weft yarn measured by rotating feed rollers and stored in a storage tube before feeding or is wound on the accumulator drum .   Tensioners by imparting a light tension to the weft yarn ,when it is being m
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Rapier weft Insertion System

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Repier Weft Insertion system -      The picking or weft  insertion system is based on modified repair principle, two carriers  entering the warp Shed  simultaneously from each side of the l oom and meeting almost half way through the shed. These are two basic type of rapier heads: 1) Loop transfer rapier machine-Gabler Principle ,  2) Tip transfer repair machine -Dewas principle.    In the Gabler system the weft  is never gripped. It is placed in a slot 'A' in the right rapier head and as the rapier advance towards the centre of the Loom, the yarn  passes from its clamped position round the head,  to the supply package in the form of hair pin .When  the head meet at the centre of the loom, the smaller left hand head , 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 repositions the weft at 'C'.  The yarn then  slides through the left
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Sluzer Shuttleless Weaving Machine/ Working Of Projectile Mechanism

Sulzer Shuttle less Weav ing Mach ine -     In this weaving machine, the weft yarn   is introduced into the shed  by means of a gripper.A tuck -in selvadge  is formed by drawing the cut weft end into the shed by means of tucking needles. The pick is then beaten up by means of cam  operated reed.      A torsion bar arrangement is used for propulsion of the gripper  through the open shed.The gripper while  travelling from left hand side to the right hand side is made up to follow a fixed path across the loom by means of a series of rake  guides which is elevated  into the shed before picking and again falls below the bottom shed line before beat up . The gripper on reaching the right hand side leaves the weft yarn ,falls down to conveyor underneath the sley and return back to the left hand side to follow to the  cycle of picking .At a time only one gripper is picked in the shed and  so gripper returns at much  slower speed than the weaving speed,many gripper  are in a circulation so th
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Sizing /Creel /Size box /Sizing Conditions

Sizing . -   In the preparation of warp , sizing make the most significant contribution to the Loom performance  during the weaving. The adequate care in a selection of warp sizing machine is a very much is essential . Creel -    Most of the modern sizing machine are equipped with automatically operated warp unwinding  mechanism. Some modern machines are built in the pneumatically operated band brake which are monitored by the computer ,where the yarn tension is measured by the detector roller with a constant warp angle. Breaking force is regulated after the comparing the measured value with the pre -set value. The creel zone Stretch is controlled  with in 0. 5 % by way of  ball bearing mounted guide roller for every two beam. Size box -     Double size box is used in most of the advanced machines. These are equipped with  individual squeezing arrangements to reduce the pickup variation along the length of warp sheet . Additional features like pre-heating of the warp prior to siz
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Electronic Systems For Textile Testing/Yarn Evenness tester

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Introduction   Textile testing always a  essential part of production and use of processes, has become even more important in a recent year as a result of new demands placed upon the product of the textile  manufacturers. Advancement in a technology has made a great impact on textile testing also. If you compare the conventional testing instrument with mordern testing instruments we will find a spectacular change in a testing instrument due  to the application of electronic. Although use of electronic system has changed ,the whole scenario in textile but in fact on test instrument is amazing .All important fibre properties can be determined by the putting the fibre sample in high volume  instrument within a few minutes by any person, otherwise it is used to take at least 5 - 6 hours and extensive skilled work by operators. Similarly by using various electronic system testing instrument have become so user friendly. that any body can be  test for various properties. Evenness testi
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