As a kind of fancy yarn, slub yarn for knitting has a yarn structure different from ordinary knitting yarn. Due to its structural changes, some of the quality inspection items used for natural knitted yarn can be used as inspection content for slub yarn, but there are obvious differences in indicators, such as weight deviation, strength weight CV value, strength CV value, etc. Some items can be used as a reference to judge the accuracy of bamboo parameters. Such as the evenness spectrum spectrum. The main technical measures for spinning slub yarn for knitting.
Analysis based on the basic requirements and quality characteristics of spinning slub yarn. First of all, make sure that the spinning machine is in good condition. For the understretch structure, it is necessary to ensure stable pressure, and there is no slack in the top roller, apron, and upper frame. For the winding and twisting system, the steel ring, spindle, and yarn guide hook must be concentric and perpendicular to reduce winding as much as possible. Tension fluctuations during the process reduce yarn breakage. It is necessary to strengthen the maintenance of spindle discs and spindle belts to reduce twist differences caused by mechanical factors. The differences between the spinning process of slub yarn for knitting and the spinning process of ordinary knitting yarn are mainly in the understretch of the back area, speed, traveler configuration, and spacing block of the spun yarn. The main factor affecting the production efficiency and spinnability of slub yarn for knitting during the spinning process is the change of slub parameters, that is, the section thickness, section length and pitch.
The twist design of slub yarn is based on the base yarn, and then the twist is determined according to the length and thickness of the slub and the quality of the cotton blend. The twist coefficient of woven fabrics is generally controlled above 380. The twist coefficient of knitted fabrics is generally controlled at around 340-360. At the transition between the bamboo knots and the base yarn, try to adjust the knot shape to be as relaxed as possible, which is beneficial to both twisting and strength.
When determining the main parameters of the spinning process, the speed of the front roller of the spinning machine, the selection of travellers, and the selection of distance blocks have a great impact on the end breakage of the spinning yarn. They should be regarded as key tasks in the spinning process, and dedicated personnel should be implemented. Make timely adjustments according to production conditions.
Since the balloon shape of slub yarn for knitting changes frequently, the running trajectory of the traveler on the steel ring is also different from that of ordinary knitting, so the wear of the steel ring is different from that of spinning ordinary knitting yarn. The inspection, maintenance and replacement of steel rings should be strengthened to prevent large-area end-breaks in the spinning frame caused by severe deterioration of the steel rings.
According to the characteristics of knitting equipment, when determining the process parameters of slub yarn, attention should be paid to the selection of slub shape. If there are no special requirements, the pen tip type should be selected to reduce shaving or even breakage when the slub yarn passes through the needle eye.
Production practice has proved that the factors affecting the uneven strength of slub yarn are much more complicated than spinning ordinary plain yarn. In addition to the factors that affect uneven strength when spinning ordinary plain yarn, slub yarn has various phenomena caused by instantaneous acceleration and deceleration. For example, issues such as power balance and speed ratio synchronization between the servo motor and the middle and rear rollers. According to experience, the speed of spinning slub yarn is 5%-10% lower than that of ordinary plain yarn, and the twist is 5%-10% higher. The purpose is to improve the strength of slub yarn and reduce the breakage rate. If the roving twist is appropriately increased, the roving basis weight and the spun yarn drafting multiple are appropriately reduced, the servo motor speed change and the spun yarn drafting can be made more reliable. The purpose of this increase and decrease is also to improve the uneven strength of the slub yarn and further reduce the spun yarn. The broken ends make the slub yarn style more in line with the craft design.
During winding, in order to further improve the quality and reduce yarn defects and breakages during the weaving process, an electronic sand cleaner can be used to effectively remove “thick slubs” that are larger than the knot thickness parameter. The normal bamboo joints are retained.
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