Popular Science | Knitted fabrics always have horizontal stripes. Why does this happen?

horizontal Stripes are a common weaving defect caused by factors such as machine adjustment and poor raw material quality during the production process of circular knitting machines. There are gen...

horizontal Stripes are a common weaving defect caused by factors such as machine adjustment and poor raw material quality during the production process of circular knitting machines. There are generally two types of weaving defects: hidden horizontal stripes and single-filament horizontal stripes. This article introduces the characteristics of circular knitting fabrics, analyzes the causes from the aspects of raw materials, mechanisms, machine parts and adjustment processes, and proposes corresponding preventive and rectification measures.

Causes of hidden horizontal bars and preventive and corrective measures

The hidden horizontal bar means During a cycle of machine operation, the size of the coils changes periodically and sparse and uneven patterns appear on the cloth surface. Generally speaking, the possibility of hidden stripes caused by raw materials is small. It is mostly caused by periodic uneven tension caused by untimely adjustment after mechanical wear, thus causing hidden stripes.

Cause of 1.1

a. Due to low installation accuracy or severe wear due to aging equipment, the horizontality and concentricity deviation of the circular knitting machine needle cylinder exceeds the allowable tolerance. A common problem occurs when the gap between the positioning pin of the large transmission gear plate and the positioning groove of the machine frame is too large, causing the needle cylinder to be unstable during operation, seriously affecting yarn feeding and unwinding.

In addition, due to equipment aging and mechanical wear, the main drive gear plate shakes longitudinally and radially, increasing the concentricity of the needle cylinder and causing deviations. Fluctuations in yarn tension can lead to abnormal loop sizes and, in severe cases, hidden horizontal stripes on the gray fabric.

b. During the production process, foreign objects such as flying flowers are embedded in the speed plate adjustment slide of the yarn feeding mechanism, causing the roundness to be affected. As a result, the speed of the synchronous toothed belt is abnormal and the yarn feeding amount is unstable, resulting in the occurrence of hidden horizontal stripes.

c. The circular knitting machine uses a passive yarn feeding mechanism, which is difficult to overcome the shortcomings of large differences in yarn tension during the yarn feeding process. It is easy to cause unexpected yarn elongation and differences in yarn feeding amount, thus forming hidden horizontal stripes.

d. For circular knitting machines that use intermittent coiling mechanisms, the tension fluctuates greatly during the coiling process, and the length of the coil is prone to differences.

1.2 Preventive and corrective measures

a. Appropriately thicken the electroplating of the positioning surface of the gear plate, and control the shaking of the gear plate between 1 and 2 wires. Polish and polish the bottom ball track, and add grease to the needle. The bottom of the cylinder is padded with a soft and thin elastomer, and the radial shaking of the needle cylinder is strictly controlled to be about 2 wires. The sinker triangle needs to be calibrated regularly so that the distance between the sinker triangle and the tail of the new sinker is controlled between 30 and 50 wires. , the triangle position deviation of each sinker should be controlled within the range of 5 wires as much as possible, so that the sinker can keep the yarn holding tension consistent during unwinding.

b. Control the temperature and humidity of the workshop. Generally, the temperature is controlled at around 25°C and the relative humidity at 75% to prevent the adsorption of flying dust caused by static electricity. At the same time, necessary dust collection measures are taken to maintain Clean and maintain the machine to ensure that all rotating parts operate normally.

c. Transform the passive mechanism into a storage sequence Actively feed the yarn mechanism to reduce the tension difference during the yarn guiding process. It is best to install a speed monitoring device to stabilize the yarn feeding tension.

d. Transform the intermittent coiling mechanism into a continuous coiling mechanism to ensure continuity during the cloth curling process and ensure Stable and uniform tension.

Causes of monofilament horizontal strips and prevention and rectification measures

Monofilament horizontal strip refers to a orIt is the phenomenon that several rows of coils are too large or too small compared to other rows of coils, and the density is uneven. In actual production, monofilament strips caused by raw materials are the most common.

2.1 Reasons

a. The yarn quality is poor, the single filament has color difference, such as tightly twisted yarn, the batch number of chemical fiber filament is not included, and the Mixing colored filaments or yarns of different yarn counts directly leads to the production of monofilament horizontal stripes.

b. The size of the yarn bobbin is greatly different or the yarn cake itself has convex shoulders and sagging edges, resulting in uneven unwinding tension of the yarn and easy to produce single-filament horizontal stripes. This is because the different sizes of the yarn packages will result in different winding points and diameters of the unwinding balloons, and there will inevitably be large differences in the change patterns of the anti-heat tension. During the knitting process, when the tension difference reaches the maximum value, it is easy to cause different yarn feeding amounts, resulting in uneven loop sizes.

c. When processing porous and ultra-fine denier raw materials, the silk path should be as smooth as possible. If a certain yarn guide hook is slightly rough or the grease is solidified, it is easy to cause multiple single filaments of the raw material to break, and the color difference of the single filaments will also occur. Compared with conventional raw material processing, the requirements for equipment are more stringent, and the finished fabric is more likely to produce monofilament horizontal stripes.

d. The machine is not adjusted in place and the needle triangle is too deep somewhere. Or too shallow, resulting in abnormal yarn tension and differences in the size of the loops formed.

2.2 Preventive and corrective measures

a. Ensure the quality of raw materials, use raw materials from famous brand manufacturers as much as possible, and have strict requirements on the dyeing and physical index changes of raw materials. The dyeing requirement standard is above 4.0, and the physical indexes vary. The coefficient of variation of the term should be small.

b. It is best to use fixed-weight silk cakes for processing. For fixed-weight silk cakes, select silk cakes with the same roll diameter and use them on the machine. If you find that the appearance of the silk cake is poor, such as silk cakes with convex shoulders and sagging edges, you must Eliminate use. When dyeing and finishing, it is best to follow the dyeing sample. If horizontal streaks appear, choose to change the dyeing to a non-sensitive color or add a horizontal streak treatment agent to eliminate or reduce the horizontal streaks.

c. When processing porous and ultra-fine denier raw materials, the appearance of the raw materials must be strictly controlled. In addition, it is best�Clean the wire path and check whether each guide wire structure is smooth. During the production process, observe whether there is tangled wool in the weft feeder. If found, stop the machine immediately to find out the cause.

d. Ensure that the depth of the pressure gauge triangle of each yarn feeding channel is consistent. Use a yarn length gauge to finely adjust the bending position of each yarn feeding triangle to keep the yarn feeding amount consistent. In addition, check whether each bending triangle is worn. The adjustment of the bending triangle directly affects the yarn tension, and the yarn tension directly affects the size of the loop formed.


1. Factors in the production of circular woven fabrics Monofilament horizontal stripes caused by raw material quality are the most common. Choosing raw materials with good appearance and good quality is very necessary for circular knitting production.

2. Routine maintenance of machinery is very important. The wear and tear of some machine parts that have been running for a long time will affect the level and concentricity of the circular knitting needle cylinder. Increased degree deviation can easily cause horizontal bars.

3. During the production process, the adjustment of the needle triangle and the sinking arc is not in place, causing abnormalities in the coils, increasing the difference in yarn feeding tension, resulting in inconsistent yarn feeding amounts, and horizontal stripes.

4. Due to the characteristics of its coil structure, circular woven fabrics have different sensitivities to horizontal stripes in fabrics of different organizations. Generally speaking, the probability of horizontal stripes appearing in single-area fabrics such as jersey is relatively high, and the requirements for machinery and raw materials are relatively high. high. In addition, fabrics made from porous and ultra-fine denier raw materials are more likely to have horizontal stripes.

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