Crossroads are a common and sensitive topic in circular knitting machines.
We will now discuss it from the following aspects. There are various forms of cross paths, including visible wide cross paths, monofilament cross paths, hidden cross paths, and the middle ones are divided into regular cross paths and irregular cross paths. We take the double-sided circular knitting machine as the object of discussion. General cross paths are mostly caused by problems with the machine itself and raw materials. The causes are:
1. The mechanical data is inaccurate. Because the assembly accuracy is not high. Or the aging of the machine and equipment, the roundness and flatness of a single piece of the needle cover, and the synchronization data exceeding the allowable range will cause changes and fluctuations in the tension of the yarn feeding, and finally lead to the size of the coil and cross paths. Such crosswalks will generally disappear after adjusting the machine data.
2. Problems with yarn feeding trays and thread feeding devices are caused by some manufacturers with a lot of fly flakes and poor dust removal systems. If the slider in the yarn feeding tray is not cleaned for a long time, the flying particles accumulated in the slider and the rubber sleeve of the slider are aging, causing the belt to slip and the speed to be abnormal. The amount of yarn feeding has a speed-dependent path. The yarn feeder accumulates flying particles, and the upper and lower gears are not in the transmission position, so that the yarn is in a negative state when the machine is turned on, resulting in cross paths.
3. Debugging issues: When debugging the machine, the needle depths of the upper and lower needle triangles are inconsistent, causing the coils on the cloth to vary in size and produce cross paths. Such cross paths are generally regular. Because the depth of the upper triangular press needle is difficult to see with the naked eye, when debugging the machine, we first adjust the lower press needle to a press needle depth position, and then adjust the upper press needle. At this time, the tension of the yarn is used as the standard. In this process, we will encounter a common phenomenon, that is, the rib strip has two straight vertical coils on the fabric surface, and the middle lane will be larger and smaller for a while. The reason is that the pressing needles are not pressed evenly. This phenomenon It is also found in cotton wool fabrics and ribbing machines, and the fabric surface will be ugly. In addition, the uneven division of the upper and lower triangular bases can also cause such cross paths. The concept of equal division is that the upper and lower parts of the circumference are not equally divided, so that the needle points of the upper and lower needles are inconsistent when forming a circle. This problem can be solved with your eyes. It’s hard to see.
4. Raw material problems. Raw material problems are more common. The resulting cross paths include yellow and white cross paths and irregular cloud spots. These cross paths can generally be solved after changing the yarn, but some are hidden cross paths. This type of cross paths are the most troublesome. , Poor yarn quality, color difference, uneven twist, and mixed yarn counts will all cause such problems. The horizontal stripes of spandex cloth are also one of the common problems. Some poor-quality spandex has more problems, such as too much stickiness and twist and fluffiness.
5. Color difference problem. Sometimes we encounter a situation where there are no horizontal paths on the blank and the fabric surface is very good, but when the blank comes out, there are all horizontal paths. At this time, the weavers will talk about bleaching and dyeing problems, and the bleaching and dyeing people will talk about weaving problems. I once heard a friend say to me: This is a color difference caused by the poor color absorption of the fiber in the raw material. It doesn’t matter if it is dyed in a light color or bleached. It seems to make sense. But I have no way of verifying whether this is really the case. I can only ask friends who are dyers to talk about this topic.
6. Creel yarn guide structure problem. This kind of problem occurs in the terry machine, especially when the F number of the open fiber yarn is high. It is generally caused by the cross path caused by the yarn guide structure being napping or tightening. This kind of cross path is not obvious, so some manufacturers’ debuggers will adjust the floor-standing creel. Check the tension between the yarn feeder and the yarn feeder by hand.
7. The problem of the stop cross path is generally the problem of the gap between the main shaft driving gear and the large plate gear, and the matching clearance between the large plate base and the large gear. The thicker the layout, the more obvious the stop cross path. The debugging of this type of cross path can be alleviated at most and completely eliminated. Unlikely, as it is factory determined.
To sum up, there are many problems with horizontal bars in the production of circular knitting machines. Specific problems should be analyzed in detail, so we try to do the following:
1. Routine maintenance of large circular knitting machines should be carried out regularly, and consumable parts should be inspected regularly and replaced in time, especially for double-sided machines.
2. To ensure the quality of raw materials, there must be strict requirements on the dyeing of raw materials and the variation of various physical indicators. The dyeing requirement should be above 4.0, and the variation coefficients of various physical indicators should be small.
3. When it comes to the issue of chemical fiber polyester network yarn, try to use good yarn. If there are cross paths, it is best to make a sample when dyeing and finishing, or change the dyeing to non-sensitive colors or bleach. In addition, you can add it to such raw materials. A horizontal stripe treatment agent to eliminate or lighten horizontal stripes. Note: This type of horizontal strip treatment agent is only suitable for chemical fibers and is useless for cotton yarn horizontal strips.
If you have other opinions, please leave a comment below.
Two additional points:
1. Inaccurate concentricity and leveling of the cloth roll surface and the needle cylinder will also cause hidden/cross paths
2. Uneven sizes of yarn or thread bobbins will also cause hidden/cross paths.
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