In recent years, there have been many reports on two new spinning methods, compact spinning and siro spinning. The effect of these two new spinning processes on improving yarn quality is also recognized by everyone. This article will introduce the two spinning methods. The characteristics of the process and the quality of the yarn are analyzed.
Although the compact spinning process is different in mechanical structure, one thing is the same, that is, after completing the drafting required by the process and before twisting, the former The wider yarn slivers output by the roller nip are gathered, making the yarn sliver width very narrow, and the single fibers are arranged more closely, and try to keep it in this state before entering the twisting zone. Although some reports say that this eliminates the “twisting triangle”, in fact the width of the yarn before and after twisting is different. Therefore, there is still a very small so-called “twisting triangle area” at the jaws of the twisting roller in compact spinning, but of course its harmfulness has been reduced to a minimum. It is precisely because of the above-mentioned yarn forming mechanism that the spun yarn spun by the compact spinning process has the following characteristics:
1. Since the single fibers in the yarn are fully straightened before twisting, They are parallel to each other and closely arranged, so at the nip of the twisting roller (also called the twist roller, because it prevents the transmission of twist), the diameter of the yarn becomes very small, so the “twisting triangle area” is basically eliminated. , because the single fibers are fully straightened and parallel before twisting, and there is no hairiness extending out of the main body of the yarn, so the yarn has very little hairiness, especially the hairiness above 3 mm is very little.
2. In spun yarn, since each single fiber is twisted in a straight and parallel state, when the single yarn is subjected to tension, the force of each single fiber is basically the same, so the strength of compact spinning is higher than that of traditional single fibers. Yarn high. And because the single fibers in the compact yarn are closely arranged and have strong cohesion with each other, this also helps to improve the strength of the yarn.
3. In the compact spinning process, the yarn is gathered after completing the draft specified by the process, so the unevenness of the yarn has not been greatly improved, but there is some improvement in the gathering area. It has a finishing effect on the yarn, and when twisting at the twisting roller nip, the transfer of the inner and outer layers of fiber is not as strong as in the traditional process, so the compact yarn has uneven slivers, and its thickness and detail indicators are better than those of traditional yarns.
4. Due to the above characteristics of compact yarn, it provides very good conditions for the next process. Compact yarn has less hairiness, so it reduces the pressure of sizing, singeing and other processes. In shuttleless looms When the weft yarn uses compact yarn, the resistance of weft insertion is greatly reduced and the efficiency of the loom is improved.
5. Because the fibers of compact yarn are closely arranged and have a smaller diameter than traditional yarns of the same number, the cloth woven with the same warp and weft density has good air permeability and a flat and smooth surface. It is an ideal yarn for high-end textiles.
Although the compact spinning process has many advantages, it also has some shortcomings, as described below:
1. Compact spinning The cost of equipment is relatively high, which increases equipment investment in spinning mills.
2. There is a suction port corresponding to each yarn. The negative pressure at the suction port varies greatly between spindles. If you want to improve the consistency, you need to add a suction port to each straw (or Each spindle position) is equipped with a control valve that can automatically adjust the air volume. This is not only costly, but also difficult to maintain.
3. Except for the great improvement in the hairiness index, other yarn indexes such as evenness, thickness, details, etc. have not improved much.
4. After the compact yarn goes through the winding process, more hairiness will be added. Siro spinning feeds two rovings at a certain distance on the same spindle position. The two rovings are drafted separately. After the yarn is output from the front roller, the two yarns are twisted together due to the twisting effect. , forming a fine yarn. Practice has proved that the yarn forms less twist after being output from the front roller and before twisting. Two weakly twisted yarns are twisted together at the center of each other to form a unique style of Siro yarn.
The characteristics of Siro spinning are as follows:
1. Because two rovings are pulled separately at the same time Extension, according to the merger theory, CX=CA/√n, in the formula, CX is the unevenness after merger, CA is the unevenness before merger, n is the number of merger roots, where n is equal to 2. So CX=0.7×CA. Of course, the above formula is theoretical data and is somewhat different from the actual situation. But it also shows:
Yarns spun using the siro spinning process have a very obvious effect on improving evenness and reducing roughness and details, which is what countless spinning mills are striving for. Our company’s experiments over the past few years and the mass production practices of many users have fully proved this point.
2. After the siro spinning yarn is output from the front roller, when twisting, the two weakly twisted yarn slivers are rolled into a siro yarn centered on each other. During the winding process, the hairiness extending out of the main body of the yarn is rolled into the yarn and is well held. Therefore, the hairiness of Siro yarn is less than that of other spinning methods, and because the hairiness is wrapped in the spun yarn by two yarn strips, the hairiness will not increase as much as other spinning methods during the winding process. This is different from other spinning methods. Unmatched by spinning methods.
3. Siro spinning yarn is basically not twisted at the nip of the front roller, so there is no so-called “twisting triangle area”, which greatly reduces fly waste in the workshop.
4. After the winding process, Siro yarn has less hairiness than compact yarn, so it has superior performance in the sizing, weaving, and singeing processes.
5.SiroDuring the twisting process of the yarn, the degree of internal and external transfer of fibers is small. After the yarn is formed, the fibers are arranged regularly. The yarn strength is better than that of single yarn and lower than that of plied yarn. In addition, Siro yarn has fewer details, which is also good for the yarn. Increasing yarn strength helps.
6. Siro spinning equipment has a simpler mechanism than compact spinning, has less equipment investment and is easy to maintain. It is easy to carry out modifications on old machines.
7. Siro yarn has similar properties to ply yarn and can replace ply yarn in many cases. However, Siro spinning does not need to go through a twisting machine, and the process flow is shorter than the conventional process, saving energy and labor.
In summary, the siro spinning process has advantages that other spinning processes cannot match, but it also has its shortcomings. place. </p
