Why do knitted fabrics appear to be horizontal?
Why do old knitwear strips appear? The horizontal bar is a relatively common woven fabric caused by poor machine adjustment and raw material quality during the production process of the circular machine, generally has two kinds of hidden horizontal strips and single-filament horizontal strips. In this paper, through the introduction of the characteristics of the circular woven fabric, the reasons for its origin are analyzed from the aspects of raw materials, mechanisms, machine parts and adjustment processes, and corresponding preventive measures are proposed. 
I. Causes of hidden horizontal bars and prevention and rectification measures The hidden horizontal bars refer to the phenomenon that the coil size changes periodically and the sparse unevenness appears on the cloth surface during the one cycle of the machine operation. In general, the possibility of causing hidden horizontal strips is small, and most of them are periodic tension unevenness caused by untimely adjustment after mechanical wear, thereby causing hidden horizontal strips.
1.1 Causes
a. Due to the low installation accuracy or severe wear due to aging of the equipment, the levelness and concentricity deviation of the circular machine cylinder exceeds the allowable tolerance. A common problem occurs when the gap between the positioning pin of the transmission large gear wheel and the positioning groove of the machine frame is too large, which causes the syringe to be not stable enough during operation, which seriously affects the yarn feeding and the retraction.
In addition, due to equipment aging, mechanical wear, causing the longitudinal and vertical sway of the main drive gear plate to increase the deviation of the concentricity of the syringe, causing fluctuations in the yarn feeding tension, resulting in abnormal coil size, serious hidden strips on the fabric .
b. In the production process, the shifting disc of the yarn feeding mechanism adjusts the foreign matter such as flying flowers in the slider, and the roundness is affected. The speed of the synchronous toothed belt is abnormal, and the yarn feeding amount is unstable, resulting in the generation of hidden horizontal strips. .
c. The circular machine adopts the negative yarn feeding mechanism, it is difficult to overcome the shortcomings of the yarn tension difference in the yarn feeding process, and it is easy to cause the yarn to be unexpectedly elongated and the difference in the yarn feeding amount, thereby forming a hidden horizontal strip.
d. The circular machine adopting the intermittent winding mechanism, the tension fluctuation is large during the winding process, and the length of the coil is easy to be different.
1.2 Prevention and Corrective Measures
a. The gear disc positioning surface is plated appropriately and thickened, and the control gear disc is shaken between 1 and 2 filaments. Polish and polish the bottom ball track, add grease to flatten the bottom of the syringe with a soft elastic body, and strictly control the radial movement of the syringe to about 2 wires. The sinker triangle needs to be regularly corrected, and the distance between the sinker triangle and the tail of the new sinker is controlled between 30 and 50 filaments. The triangular position deviation of each sinker is controlled within 5 filaments as much as possible, so that the sinker is retreating. Keep the grip tension consistent during the circle.
b. Control the temperature and humidity of the workshop. Generally, the temperature is controlled at about 25 °C, and the relative humidity is controlled at 75% to prevent the adsorption of flying dust caused by static electricity. At the same time, necessary vacuuming measures are taken to maintain cleanliness, strengthen machine maintenance, and ensure the operation of various rotating parts. normal.
c. Transform the passive mechanism into a storage type active yarn feeding mechanism, reduce the tension difference in the yarn guiding process, and preferably install the speed monitoring device to stabilize the yarn feeding tension.
d. The intermittent coiling mechanism is transformed into a continuous coiling mechanism to ensure the continuity of the fabric curling process and ensure the stability and uniformity of the coil tension.
2. Causes of monofilament horizontal strips and prevention and rectification measures Monofilament horizontal strips refer to the phenomenon that one or several horizontal coils on the surface of the fabric are too large or too small and unevenly distributed compared with other transverse coils. Monofilament strips caused by raw materials are most common in actual production.
2.1 Causes
a. The yarn quality is poor, and the color difference of the monofilament is such as tight silk, non-woven number of chemical fiber filaments, non-colored filaments or different yarns, which directly lead to the generation of monofilament strips.
b. The difference in the size of the bobbin is large or the shoulder and the sag are formed in the silk cake itself, resulting in uneven yarn unwinding tension and easy to produce a monofilament cross bar. This is because the difference in the size of the bobbin will make the winding point and the diameter of the unwinding balloon different, and the variation law of the deflagration tension will inevitably have a large difference. During the weaving process, when the tension difference reaches a maximum value, it is easy to cause the yarn feeding amount to be different, resulting in uneven coil size.
c. When processing with porous and ultra-fine denier raw materials, the thread path should be as smooth as possible. A certain yarn guide hook is slightly rough or the grease stain is solidified, which easily causes the single filament of the raw material to break, and the monofilament color difference will also occur. Compared with the processing of conventional raw materials, the requirements for equipment are more severe, and the fabric is more likely to produce monofilament strips.
d. The machine is not adjusted properly, and the needle triangle is too deep or too shallow at some point, so that the yarn tension is abnormal, and the size of the formed coil is different.
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