Abstract:

Objective With the continuous increase of spindle position of the rotor spinning machine, when there is an occasional end breakage in a certain spindle position during the spinning process or when the full roll is automatically changed, a single spindle single-control manipulator splicing technology gradually replaces the splicing mode of the splicing trolley. This technology achieves automatic single spindle splicing through programmable logic controller (PLC) dual-level control. However, due to the unclear mechanisms underlying each splicing process step, it cannot flexibly adjust automatic splicing parameters based on varying process parameters, spinning component structures, or spinning materials. For this reason, this paper discusses in depth the timing control method of single spindle automatic starting and splicing process after yarn breakage, and introduces the development of a continuous spinning technology that can achieve high quality and high-speed splicing.

Method The function of single spindle automatic splicing were firstly analyzed, and an integrated control system based on PLC multi-level control technology was constructed to realize the function of single spindle automatic splicing. Then, a mathematical model of single spindle automatic starting and splicing was constructed by analyzing the function of single spindle automatic splicing and its mechanism, so as to control the reciprocating motion of splicing robot arm and the morphological structure of the splicing between the seed yarn and the fiber flow in the rotor cup. On this basis, 30 groups of experiments were designed and the results were compared and analyzed by a microscope and image processing (MatLab2023b).

Results The success rate of the splicing was 100% for the 30 sets of experimental splices carried out by manually interrupting the yarns, of which 10 sets were used for MatLab image processing and strip dryer to test the yarn diameter, and the other 20 sets were adopted to test the breaking strength of single yarns. The results were analyzed by comparing the parameters of the 30 tubes of yarns tested. The 10 groups of images processed yarns effectively removed the noise, hair feathers and other interference in the image, and obtained a clear yarn trunk, which laid the foundation for the accurate calculation of yarn diameter, and the average diameter of the splice was 0.578 mm, which was 1.778 times of the normal yarn diameter. In 20 groups of breaking strength tests, the average strength at the splice was 10.76 cN/tex, which was 88.1% of the average strength of 12.21 cN/tex of the designed normal yarn, all of which conformed to the quality index for splice of related industry standards.

Conclusion This paper is based on the automatic rotor spinning platform which can realize the function of single spindle automatic splicing, through the analysis of single spindle automatic splicing and splicing mechanism, constructed the corresponding mathematical model to guide the program to control the timing movement of the relevant mechanical structure, solved the problem of how to splice the yarn quickly after the yarn breakage of individual spindles due to the occasional breakage or full roll change in the process of rotor spinning, and verified the accuracy of the model through the relevant experiments. The digital splice technology with flexible adjustment of splice process parameters is realized. Although the final experimental results meet the relevant industry standards, the CV value of the yarn splice section is not satisfactory enough, which is a direction that needs to be further investigated in the future.

Key words: rotor spinning, single spindle with single control, automatic starting, automatic splicing, splicing model, digitalization and continuous spinning