How to improve sizing quality by reforming equipment？
Release time: 2021-06-16
Sizing is an important part of weaving department. The quality of warp sizing is directly related to the normal weaving process and the final quality of fabric. Therefore, textile enterprises have always attached great importance to sizing process. In this issue, we share with readers the experience of improving sizing quality through equipment transformation.
Method 1: the warp frame was modified to improve the unwinding tension unevenness of sizing machine
At present, most sizing machines adopt negative unwinding mode, which is often equipped with yarn tension adjustment device on the axle frame. There are two common types: belt hammer type and elastic compression clamp type. The adjustment effect is greatly affected by the operator's experience level. Once the adjustment is not in place, the uneven tension will not only cause yarn waste, but also cause weaving difficulties and affect the quality of grey fabric. In practice, we found that the problem of unevenness of unwinding tension of sizing machine can be solved by modifying the unwinding part of warp shaft and adding tension sensing device.
For this reason, we have installed fixed short shafts on the warp frames on both sides of the sizing machine, so that the swing frame can swing around the short shaft. A pointer is set on the swing frame, and the tension roller is installed on the swing frame, which can swing with the swing frame. The swing frame is a double arm structure. The tension roller is installed on one arm, and the counterweight is installed on the other arm, which can prevent the guide roller from producing large additional tension on the warp. During unwinding, the tension roller senses the yarn tension on the warp layer. As long as the display result of each axis pointer is consistent, the tension between the axes can be consistent. The tension can be achieved by adjusting the clip on the warp shaft.
Through repeated tests, we found that the following points should be paid attention to when making the tension sensing device: the short shaft should not be made into a through shaft, and the length should not be within the working width of the warp, so as not to affect the operation of the warp; The tension roller can be made of seamless steel pipe with a diameter of 50 mm. Small shafts are welded at both ends and the surface is antirust treated; The tension roller should not be too thin to prevent bending deformation from affecting its rotation flexibility; The pendulum counterweight must be adapted to the quality and tension of the guide roller to prevent the yarn from being over stretched. In addition, in the production process, we should pay attention to the yarn unwinding mode, do not use mutual unwinding mode, to ensure the independence of each warp tension. Through sizing practice of warp 72.9 tex flax viscose blended yarn, the expected effect has been achieved.
Method 2: three sizing slots sizing machine was used to eliminate the big difference of warp coverage
At present, a remarkable feature of sizing technology is that on the basis of high count and high density, sizing technology of different diameter fiber and yarn dyed fabric varieties has developed rapidly, but these sizing technologies still have some shortcomings. For example, due to different fabrics, the proportion of different diameter fibers in the total number of warps will be greatly different. Sometimes, the total number of warps is nearly 10000, and the number of different diameter fibers is less than 1000, or even less. This makes the warp coverage coefficient of the two sizing slots of the double sizing slot sizing machine very different, and it is difficult to control the warp elongation and tension, thus affecting the sizing quality. At the same time, the yarn dyed fabric is developing towards the direction of high difficulty, not only the total number of warp is increasing, but also the pattern and color are changing a lot, and the organizational structure tends to be complex. In order to prevent the different colors of warp from shifting each other during sizing, different sizing grooves need to be used separately for sizing, which leads to the fact that the double sizing groove sometimes can not meet the warp sizing requirements of multi-color fabric varieties, and the three sizing groove sizing machine is applied.
Taking ga311 three size slot sizing machine as an example, through practical production, we found that the same product has many advantages under the same Sizing Pressure and the same size formula: due to the reduction of sizing and drying coverage coefficient, the hairiness of sizing is reduced by 20%, the size film is more uniform, and the improvement rate of sizing wear resistance is increased. At the same time, we also found that the loom efficiency can be increased by more than 10% when sizing on ga311 sizing machine. When ga311 sizing machine produces multi-color products, it can meet the requirements of different color yarn sizing by slot and drying by layers, reduce the problem of "color matching" between yarn and yarn, reduce the hairiness of sizing yarn and improve the abrasion resistance of yarn, and reduce the self color fiber fouling and cross color caused by the fiber shedding of dark warp into the light color area of fabric in the process of weaving friction, The first-class product rate of the product is excellent, and the number of defective fabrics with sizing pollution is significantly reduced.
Method 3: change the structure of the pressure roller to solve the problem that the pressure roller can not hold the yarn
GA308 sizing machine is an advanced double groove sizing machine in China. In the process of using the sizing machine, the operator once reflected that the middle part of the pressure roller could not hold the yarn, and the middle part of the yarn was seriously retracted to the dry area when cutting the yarn on the lower axle. When the operator increased the pressure, the greater the pressure, the more serious the yarn retraction.
It is generally believed that the pressure is evenly distributed along the length direction of the roller, and the yarns on both sides and in the middle are pressed with the same pressure. However, in fact, because the traction roller and pressure roller are not rigid, they will deform under pressure. The greater the pressure is, the greater the deformation will be. The direction of deformation will increase the pressure of yarn at both ends of the two rollers and the pressure of middle yarn. When the pressure reaches a certain level, the pressure at both ends of the two rollers will increase rapidly, while the pressure at the middle will decrease, Even the gap appears in the middle of the two rollers, and the pressure on the yarn disappears.
Through the analysis, we have mastered the law of force deformation of the traction roller, that is, there is a peak value of yarn pressure in the middle of the roller, and the pressure of the roller on the yarn increases when the pressure increases at the beginning; When the pressure reaches the peak value, the pressure on the yarn in the middle of the roller will decrease with the increase of the pressure, and the pressure on the yarn in the middle of the roller will disappear with the further increase of the pressure. There is an interval where the greater the pressure, the looser the yarn. In fact, this situation also exists in the sizing roller. In order to solve this problem, the designer changed the structure of the grouting roller, connecting the extension shaft with the head end of the roller, and pressurizing at the head end of the roller. Instead, the extension shaft is connected with the middle of the roller, and pressurizing at the middle of the roller. In addition to solving the problem of loose yarn caused by too much pressure in the middle of the towing roller, and increasing the stiffness of the roller, we also connected a pressure regulating valve in series in the pressure air circuit of the towing roller to adjust the pressure of the pressure regulating valve to the pressure corresponding to the larger pressure on the yarn in the middle of the roller, which can effectively prevent the occurrence of excessive pressure.