The unevenness of spinning yarn is caused by many factors. Therefore, we should improve the design of drafting device, improve the control ability of fiber movement and reduce drafting wave, strengthen equipment management, ensure the machine in good working condition and reduce mechanical wave, strengthen the mixing, loosening, deburring and carding of raw materials, and reasonable control of semi-finished product quantity in each process and improvement of semi-finished product quality are the fundamental ways to improve yarn evenness.
(1) Reasonable selection of technological parameters: In production, reasonable technological parameters should be determined by comparing spinning tests according to the characteristics of products, the properties of spinning raw materials, the structure of roving and the type of drafting device used. When yarn quality requirements are high but necessary effective measures are lacking, the total draft and local draft distribution should not be close to the upper limit allowed by the model, and should be controlled on the small side, so as to improve yarn evenness. Roller gauge, roving feeding quantity and drafting type should be suitable for local drafting multiple. Roller pressure should be stable and uniform to ensure stable drafting efficiency.
(2) Reasonable arrangement of friction boundaries: Under certain conditions of drawing type, the distribution characteristics of friction boundaries have been basically fixed, but the distribution of friction boundaries can be changed and the control state of fibers can be improved by properly adjusting the distance between drawing rollers and properly moving forward or backward roller.