Open-end spinning is one of the most important spinning methods. Since the production speed is limited in ring spinning, it is an alternative spinning method.
DUTIES
1- To open and clean the fiber group that comes in the form of bands until it becomes a single fiber.
2-To bring the fibers together in a regular way and to twist them.
3- Obtaining the desired number of yarn.
4- Winding the yarn in bobbin form.
WORKING PRINCIPLE
Usually the first or second passage draw frame (almost always) or card sliver is fed to the spinning machine. The sliver comes from circular or rectangular cans located just below the spinning unit and passes through the sliver guide via the feed roller and the feeding table to the rotating bitter rollers. The rotating feed roller clamps the drawstring sliver and pushes it over the feed table towards the opening roller housing. Thanks to the leaf spring mechanism on the feeding table, tight clamping of the drawstring band against the feeding roller is ensured.
In the event of a yarn break, the feed clutch is disengaged, thereby stopping the sliver feeding process automatically by stopping the feed roller. The signal that enables this is generated by the thread polling device (yarn monitor). In conventional ring spinning, the fiber bundle – ie the draw frame – is provided as a whole with sufficient cohesion during feeding and is only thinned during the spinning process. In rotor spinning, the fiber bundle is opened up to a single fiber. This process is mainly carried out by the painful roller.
This roller with saw teeth combs the tuft of fiber caught between the feed roller and the feed table; transfers the fibers pulled from the tuft to the fiber channel. Air flow is required to transfer the fibers from the opening roller to the rotor via the fiber channel. This current is provided by the main channel in the spinning zones and then by the vacuum in the rotor housing. Vacuum is provided by the central fan as a result of the suction provided by the small channels in each rotor bearing. To create this negative pressure, the rotor box must be sealed as tightly as possible. Most of the transferred air enters through the slit where the debris is removed and very little through the suction pipe. Trash in the incoming strip as a result of the centrifugal force of the drilling roller is removed through an opening in the drilling roller casing. The removed trash falls on a conveyor belt and can be cleaned with the suction nozzles on both sides of the machine. The suction air in the fiber channel lifts the fibers from the surface of the blower roller and drags the fibers towards the rotor. During this movement, both the air and the fibers are accelerated due to the shape of the feed tube. In this way, a second draw is achieved following the nip zone/drying roller, resulting in further separation of the fibers.
Moreover, an increase in the partial straightening of the fibers is achieved in this air flow. Since the circumferential speed of the rotor is several times the speed of the fibers, a third draft is achieved when the fibers reach the rotor wall. This is a very important feature, because it clearly affects the orientation of the fibers in a positive way. The final straightening of the fibers is achieved by sliding the fibers down the rotor wall towards the rotor groove under the influence of the enormous centrifugal force acting inside the rotor. On average, one to five fibers (in one region) exit the fiber channel at the same time. After sliding down the rotor wall, it accumulates longitudinally in the rotor groove. Due to the constant freezing of the rotor under the exit of the fixed fiber channel, the fiber is continuously accumulated in the groove, the fibers are constantly falling into the groove (ie, the fiber is deposited on the fiber). In this way, a continuous fiber ring is obtained in the groove. This process is called back dubbing. If nothing else is added, the rotor will soon become clogged. However, since the sole purpose is to obtain yarn from these fibers, the free end of the yarn is allowed to extend from the rotating axis towards the rotor circumference. The centrifugal force acting at this point (more than 100 times the mass of the fibers) presses the yarn end firmly against the rotor groove wall, just as it does to the fibers in the ring. Thus, the yarn end sticks to the rotor wall. As the rotor rotates, it advances the yarn along with it, and the yarn starts to rotate around the nozzle like a crank arm. Each turn of the rotor gives one turn of true twist to the yarn.
When the yarn reaches the maximum twist value determined by the acting forces, it starts to rotate around its own axis, that is, it starts to roll in the rotor groove. Now the open yarn end is located in the joining zone above the strand of parallel fibers; Thus, the brush-like yarn end rotates around itself, catching the next fibers and twisting to form the new yarn part, the newly formed part catches the next fibers and gives twist, and so on. Thus, the yarn continues to be spun continuously. It is imperative that this yarn is pulled from the rotor, this process is carried out by the drafting rollers through the yarn compensation (balancing) bar and It is turned into a cross-wound coil by the winding cylinder.
spinning elements
The basic spinning elements in the open-end machine are located inside the spinbox. The spinning elements included in the spin box are:
1-Opening roller
2- Rotor
3- Output level
Opening roller
The task of the opening roller is to open the fiber mass in the form of a band until it becomes a single fiber and convey it to the rotor with the help of the feeding channel. The opening roller is covered with serrated clothing.
Opening roller clothings differ according to fiber types.
Rotor
The rotor is the basic spinning element and is the part where the yarn is formed.
The single fiber fiber from the opener is gathered together inside the rotor. The fibers combine with the yarn tip suspended into the rotor and twist with the rotation of the rotor. There are various types of rotors according to the yarn count and properties.
outlet nozzle
After the fibers in the rotor are twisted and added to the yarn structure, they are taken out by passing through the yarn drawing nozzle and the exit channel following it at an angle of approximately 90°.
Different outlet nozzles are used according to the yarn count and twist amount.
Yarn waxing device on rotor (Open-End) machine
Especially knitted products (the thread makes sharp turns around the needles during production) thick threads in production can cause problems such as thread breaks and high wear. Knitting yarns are often paraffinized to improve running performance. On the rotor spinning machine this process can be carried out directly in the spinning zone. According to the results of the mill, the maximum reduction in the friction coefficient up to 40% is achieved by the waxing process as it is generally applied (50 – 0.5 g per kilo of yarn). The type and quality of the paraffin is decisive in the optimum (appropriate value) waxing process. Paraffins differ in hardness, melting point and penetrating properties and should be selected according to the raw material used, yarn type and knitting process requirements. Waxing devices also differ in the paraffin blocks used. In addition to longer run times, wider paraffin blocks reduce the need for wax regeneration. In this context, over-waxing is just as harmful as under-waxing, and both situations lead to high coefficients of friction. The waxing device is placed between the delivery rollers and the bobbin so that the thread lubrication process takes place thanks to the adhered wax particles as the thread passes over the paraffin mass. Since the yarns are bent sharply on the needles of the knitting machine, these particles are rubbed to ensure a smooth knitting process. The paraffin block will ensure constant contact by means of a spring.is pushed into the appropriate position. In yarn breaksThe rotating paraffin block is stopped. waxing deviceAlways balance spring or thread tension bar.Requires a yarn balancing device. waxingon the top or bottom of the deviceby caps and paraffin falling into the spinning cansIt is prevented from contaminating the feeding belts.
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