Wednesday, May 16, 2012
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Weaving machines are classified according to their filling insertion mechanism. The classification is as follows:
2. Shuttle-less
- Projectile
- Rapier
- Air-Jet
- Water-Jet
Shuttle Weaving
In shuttle weaving, a shuttle that traverses back and forth across the loom width, inserts the filling. Shuttles can be made of wood or plastic. Filling yarn is wound on the quill and the quill is placed in the shuttle. As the shuttle move across the loom, the filling yarn is unwound from the pirn and lay in the shed.
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| Fig: Basic Weaving Mechanism |
Projectile weaving machines use a projectile equipped with a gripper to insert the filling yarn across the machine. The gripper projectile draws the filling yarn into the shed. The Projectile glides through the shed in a rake- shaped guide. Braked in the receiving unit, the Projectile is then conveyed to its original position by a transport device installed under the shed.
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Fig: Projectile Weaving |
In Rapier 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 the cycle. A rapier performs a reciprocating motion.
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Picture: Weft insertion by rapier |
Rapier weaving machines can be of two types:
2. Double Rapier Machines: Two rapiers are used in these machines: one rapier, called the giver, takes the filling yarn from the yarn accumulator on one side of the loom, brings it to the center of the machine and transfers it to the second rapier which is called the taker. The taker retards and brings the filling yarn to the other side. Similar to the single rapier machines, only half of the rapier movements are used for filling insertion.
Air-Jet Weaving
The air jet weaving machines are the weaving machines with the highest weft insertion performance and are considered as the most productive in the manufacturing of light to medium weight fabrics, preferably made of cotton and certain man-made fibers (sheets, shirting fabrics, linings, taffetas and satins in staple yarns of man-made fibers); it has anyway to be pointed out that technically positive results are obtained at present also with heavy weight fabrics (denims) and that some manufacturers produce also machine models for terry production.
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Fig: Air-Jet Weaving |
A water-jet weaving machine inserts the filling yarn by highly pressurized water. The relative velocity between the filling yarn and the water jet provides the attractive force. If there is no velocity difference, then there would be no tension on the yarn results in curling and snarling of the yarn. Water-jet weaving machine can only be used for hydrophobic fibers.
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Fig: Water-Jet Weaving |
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