Research And Design Of Automatic Strip-off Control System Of Drawing Frame Based On PLC

With the development of the technology of the drawing frame, the delivery speed has been greatly improved, which results in sharp increase of the frequency of replacement of cylinders. The speed and success rate of strip-off operation restrict the productivity efficiency of the drawing frame directly. As the domestic research of automatic strip-off technology are very few, this paper has studied on the structures and theories of strip-off machine, and then designed a new method of automatic strip-off with high-reliability, wide applicability, high success rate. Furthermore,the control system of hardware part and software part has been designed.Research work of this paper can provide theoretical support for the design of the new automatically strip-off system and technical support to improve the level of automation of the drawing frame.In this paper, the main work is as follows:(1)Studied on technology of the strip-off and analysed the theories of the automatic strip-off method from three aspects, including the friction force distribution, shift theory and drawing theory. It provides theoretical support for the design of the new automatically strip-off system.This paper proposed a method of the fine strip-off based on digital servo control.The digital control of drawing roller speed and the draw ratio make fiber to form a section of the fine sliver according to settings. And then it will be moved to the place between coiler and cylinder. During can-doffing, the pulling force made from the displacement and pressure and friction from the sliver coiler will act together to separate the sliver realizing automatic strip-off.(2)Then according to the requirements of technology of the fine strip-off based on digital servo control,the paper made a overall program of the control system and the analysis and design of its hardware systems and software systems. Furthermore, control system of hardware part and software part has been designed. Hardware system mainly includes: Programmable Logic Controller controls frequency converter and the main motor to change the speed of the front roller by conveyor and spindle. And the PLC also controls servo drives and servo motors to change the speed of the middle roller and the back roller by conveyor belts and train wheel group. Hardware system achieves interacting with a computer and parameters setting through the touch screen. The software system mainly includes: to design programming to control frequency converter, servo drives and so on, as well as programming design to the fine strip-off parameters setting and touch screen setting.(3)Designed a control system of automatic breaking of fine slivers of the drawing frame from the cooperative enterprise.In experiment four kinds of cotton material: cotton, viscose, fiber and blending were used, and the statistics and analysis of the experimental data were carried out. And made the comparison of success rate and time of different ways of sliver breaking of cotton. The results show that the method of fine strip-off has broader applicability and higher success rate when compare with other domestic strip-off methods in consideration of the time and the success rate.(4)Made a summary of the study of the automatic strip-off technology and discuss the subsequent study direction.