Air-Jet Spinning

The crucial factor when increasing the spinning speed is the twist insertion. Ideally, the mechanically moved mass is reduced to a minimum. Pneumatic methods have hence come into focus in recent years. In addition to higher yarn speed, wear of machine components owing to friction is also expected to be reduced. At present, there are two machine manufacturers offering air-jet spinning machines, Murata (MVS process, introduced 2003, Japan) and Rieter (2011, Switzerland). 

The carded sliver is drafted, similar to other spinning principles, on draw frames and then fed into the machine. The draft in the air-jet spinning machine is around 40- to 200-fold. Due to the high spinning speed of up to 450 m/min, the drafting 

The outer fibers of the yarn rotate around the core. A liber embedded into the yarn is stretched between the spin cone and the last nip-point in the drafting roller pair until the rear end of the fiber is released from there. After passing the mouth of the air jet, the fiber ends are strutted by the air flow inside the jet and wrap themselves around the spin cone (Fig. 3.22). Those fibers are wrapped around the yarn body consisting of parallel fibers during take-up. 

The typical structure of an air-jet spun yarn is shown in Fig. 3.23. The yarn consists of a parallel yarn core with wrapping fibers (single or in groups). This is the 

Similar to OE-rotor spinning, the yarns are directly wound onto cross-wound bobbins. Drawbacks compared to conventional spinning processes are the high investment and the difficult start of the spinning process. Another disadvantage is the removal of short fibers, hence only medium to long fibers are suitable for this process. At present, mainly 100% cotton or cotton blends with polyester are used. See Fig. 3.24 for an example of an air-jet spinning machine. 

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Arcraft structures Arcraft windshields Ar drying Ar electrode Arex Ar filters Arfocon Ar fresheners Ar hydrocarbons Air-jet spinning Aliens... 

Air filters Airfocon Air fresheners Air hydrocarbons Air-jet spinning Airlens... 

Where polymeric fibres are mixed with natural fibres, the continuous multifilaments are cut into lengths according to the mean length of the natural fibres. The fibre-mix is then made into yams via ring spinning, rotor spinning or air-jet spinning. 

Air Jet spinning n. A spinning system in which yarn is made by wrapping fibers around a core stream of fibers with compressed air. In this process, the fibers are drafted to appropriate sliver size, then fed to the air jet chambers where they are twisted, first in one direction, then in the reverse direction in a second chamber. They are stabilized after each twisting operation. 

Air-jet spinning 116 Amorphous regions 54 Animal fibers 43 Appret 271 Asbestos 49 Atlas (Satin) weave 151... 

The introduction of nonconventional spinning technologies in the 1970s, such as open-end rotor and friction spinning and air-jet spinning in recent years, led to a 10- to 15-fold increase in yarn production speed over the last four decades. 

The air jet textured yam process is based on overfeeding a yam into a turbulent air jet so that the excess length forms into loops that are trapped in the yam stmcture. The air flow is unheated, turbulent, and asymmetrically impinges the yam. The process includes a heat stabilization zone. Key process variables include texturing speed, air pressure, percentage overfeed, filament linear density, air flow, spin finish, and fiber modulus (100). The loops create visual and tactile aesthetics similar to false twist textured and staple spun yams. 

Goldberg and Rubin [Ind. Eng. Chem. Proce.s.s Des. Dev., 6 195 (1967)] showed in tests with a disk spinning vertically to the foam layer that most mechanical procedures, whether centrifugation, mixing, or blowing through nozzles, consist basically of the application of shear stress. Subjecting foam to an air-jet impact can also provide a source... 

In air gap spinning, the solution of the aramid is forced through a spinneret. The face of the spinneret is in contact only with a gas, usually air. After travelling a short distance through the air, the solution in the form of a fine jet enters a coagulant. 

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