Control scheme of friction winding system of film
Article Source:This siteData:2020-07-16
Control scheme of friction winding system of film blowing machine
Process requirements:
1. The thickness of the extruded film is completed by changing the speed ratio of the main motor and the induction motor, so the steady-state speed accuracy of the frequency converter is high, and the fluctuation of the speed will cause the uneven film thickness;
2. Tension control is required between the take-in and the second nip roller, the second nip roller and the left and right winding. Different materials have different tension requirements, and the tension must be independently adjustable;
3. The take-up shaft leans on the take-up rubber roller and relies on the friction between the take-up rubber roller and the take-up shaft to drive the take-up shaft to rotate, thereby retracting the material on the shaft. The tension of the material has nothing to do with the roll diameter. ；
plan description:
1. Use the speed difference method for tension control;
2. Use the high-speed pulse port to ensure the basic synchronous proportional relationship between the take-in, the second nip roller, and the winding roller, and then use the tension potentiometer to set a superimposed speed to generate a speed difference with the system speed to form tension;
Program advantages:
1. The tension is generated by the speed difference. The frequency converter works in the open-loop vector control speed mode, and the dynamic response is fast, which overcomes the small acceleration tension of the torque motor and the large deceleration tension;
2. During speed control, the motor has a constant torque output. When the line speed and tension are constant, the speed of the winding rubber roller remains constant, and will not change due to changes in material diameter, load, etc., so it overcomes the need to continuously adjust the output torque in order to maintain a constant tension when the torque motor changes from empty to full Shortcomings. The system is easy to operate.
