Causes of hidden horizontal stripes and preventive and corrective measures
Hidden horizontal stripes refer to the phenomenon that the coil size changes periodically during a machine operation cycle, resulting in sparse and uneven appearance on the fabric surface. Generally speaking, the possibility of hidden horizontal stripes caused by raw materials is small. Most of them are caused by periodic uneven tension caused by untimely adjustment after mechanical wear, thus causing hidden horizontal stripes.
Causes
a. Due to low installation accuracy or serious wear caused by aging of equipment, the horizontality and concentricity deviation of the circular knitting machine cylinder exceeds the allowable tolerance. Common problems occur when the gap between the positioning pin of the transmission gear plate and the positioning groove of the machine frame is too large, resulting in the cylinder not being stable enough during operation, which seriously affects the feeding and retraction of the yarn.
In addition, due to aging of equipment and mechanical wear, the longitudinal and radial shaking of the main transmission gear plate increases the concentricity of the needle cylinder and causes deviations, resulting in fluctuations in the feeding tension, abnormal coil size, and serious hidden horizontal stripes on the grey cloth.
b. During the production process, foreign objects such as flying flowers are embedded in the speed adjustment slider of the yarn feeding mechanism, affecting its roundness, abnormal speed of the synchronous toothed belt, and unstable yarn feeding, resulting in the generation of hidden horizontal stripes.
c. The circular knitting machine adopts a negative yarn feeding mechanism, which is difficult to overcome the disadvantage of large differences in yarn tension during the yarn feeding process, and is prone to unexpected elongation of the yarn and differences in yarn feeding, thereby forming hidden horizontal stripes.
d. For circular knitting machines using intermittent winding mechanisms, the tension fluctuates greatly during the winding process, and the length of the coils is prone to differences.
Sinker
Preventive and corrective measures
a. Appropriately thicken the positioning surface of the gear plate by electroplating, and control the gear plate to shake between 1 and 2 threads. Polish and grind the bottom ball track, add grease and use a soft and thin elastic body to level the bottom of the syringe, and strictly control the radial shaking of the syringe to about 2 threads. The sinker needs to be calibrated regularly, so that the distance between the sinker cam and the tail of the new sinker is controlled between 30 and 50 threads, and the position deviation of each sinker triangle is controlled within 5 threads as much as possible, so that the sinker can maintain the same yarn holding tension when withdrawing the circle.
b. Control the temperature and humidity of the workshop. Generally, the temperature is controlled at about 25℃ and the relative humidity is controlled at 75% to prevent the phenomenon of adsorbing flying dust caused by static electricity. At the same time, take necessary dust removal measures to maintain cleanliness and hygiene, strengthen machine maintenance, and ensure the normal operation of each rotating part.
c. Transform the negative mechanism into a storage sequence positive yarn feeding mechanism, reduce the tension difference during the yarn guiding process, and it is best to install a speed monitoring device to stabilize the yarn feeding tension.
d. Transform the intermittent winding mechanism into a continuous winding mechanism to ensure the continuity of the cloth winding process and ensure the stability and uniformity of the winding tension.
Post time: Jun-04-2024