Design And Implementation Of The Pressure Control System For Twin Extruder

With the rapid development of rubber industry, the design and manufacture of equipment for rubber mixing machines in our country has achieved the level of advanced countries in the late 1990s, which can satisfy the requirement of the domestic production of tyre. Except for the super mixer, the other machines such as mill, mixer and extruder are all manufactured in our country. Furthermore, the rubber machines manufacutured in our counctry have been exported to other countries. The rubber mixing machines are the inevitable devices in rubber industry. The capability of the rubber machine have a direct effect on the quality of the rubber mixing. The machines which are often used are the mill, mixer and the auxiliary equipments of them. The system of extruder is one of the most important component in the product line. So the requirement on the pressure control and velocity control is very severe.Now, in the field of the rubber extruder manufacure, the speed control of the extruder is still simply implemented by the detection of the pressure transformer which has a share of more than 80% of all the control method and can satisfy the requirement of the customers in a certain extent. But, the shortcoming of this method is that there is obvious fluctuations on the extruding pressure and velocity of the motor, which will worsen the stability of product.In this paper, in order to get over the shortcoming of the pressure control, the feedback of the motor curcuit is introduced in the PLC programme. When the amount of the rubber become more, the load of the motor will increase simultaneously. Then the motor, curcuit will increase as the load. When the motor curcuit increase, the motor will be controlled to slow down and vice versa. The application of the Fuzzy-PID control to the pressure and velocity is also discussed. The experiment data is acquired by monitoring the feedback of the pressure and velocity. The experimetn result shows that the Fuzzy-PID control can restraint the fluctuation of the twin extruder below±50 Bar and so have a better performance than the traditional control method. As is adjusted more quickly and more effectively, the extruding products can have higher quality than before. All these studies is based on the Pressure Control System of Twin Extruder of the Dalian Rubber & Plastics machinery Corporation Limited.