Plastic Film Production Line Transformation Based On PLC

In the process of BOPET Film Production, for different size of thickness, it is need diverse precision requirement of the resin's humidity, the melt temperature and the extrusion pressure. The traditional method of using relay for control can hardly meet the requirements of both lower the cost of the improvement of the production line and improve the level of the safety and economy of the production line. So it is necessary to modify the electrification of the production line.This article firstly introduced the present situation of the research of BOPET Film Production and the trend of its development, emphasis on analyzing the methods and the problems faced in the temperature control of the production process.The accurate control of the temperature of the mold and dies of the extruder is one of the important technologies which related to the quality and the performance of product. According to the features of the extruders' temperature control system that parameter time varying, large time delay and strong coupling. In this paper it used the adaptive setting strategy which combined with conventional PID and the fuzzy control, which plays the rapidity of the fuzzy control meanwhile using the PID control to make up the defects of inadequate precision and poor accuracy. By the simulation it is show that this method is useful for the systems which parameter time varying, pure time delay and strong coupling. It has good shadowing property and it has achieved satisfactory control effects in the practical operation.Based on the requirements of the production process of the film, the BOPET film production control system is designed which based on the field bus technology, and the system is of functions of detection, control and management. After transformation, the system is a level 2 process control system. It used S7-300 PLC produced by Siemens companies for the basic automatic control which realizes the control of the equipment running like the heater, the draw machine, the tractor. As well as it used industrial computer produced by advantech co. for the monitoring station which is used to complete the functions of monitoring, alarming and tabulation. Also the operation of the system is very simple, the picture innervation is visual, the control effect is well, the reliability and the stability have greatly improved. It is proved by long time running that the equipment running well, the maintenance cost decreased, the product quality improved and the enterprise economic benefit increased.