Tension control in slitting machine

Tension control is directly related to the quality of the finished product after slitting when slitting rolls, especially thin films and foils that are stretchable. Sometimes if the tension control is not ideal, the material even will break during the slitting process, which will cause the slitting to fail.

Common tension control methods in general film slitting machines include automatic tension control and taper tension control.

Automatic tension sensor control and taper tension control are two different solutions mostly used in slitting machines.

Automatic tension control is realized by tension sensor and signal amplifier with magnetic powder brake or motor. The user first sets the tension used for slitting the current material on the tension controller. The tension sensor detects the pressure of the material on the guide roller installed on the tension sensor between the unwinding part and the winding part of the slitting machine, and then convert pressure variations into an electrical signal, amplify the signal by the signal amplifier, and input to the PLC. The PLC calculates the motor torque or brake torque compensation value that matches the current speed, and outputs it to the unwinding side and the rewinding to adjust the torque, so as to realize the automatic control of the constant tension of the slitting machine. This kind of tension control method is mostly used for high-speed slitting of materials with uniform thickness, smooth and non-sticky surfaces, and there is no frequent and large vibration of the material tension during the slitting process.

The taper tension control is actually regarded as automatic control. The difference from the automatic sensor controlis that the user needs to cut and set the initial tension of the unwinding and receiving and the decreasing and increasing slope. The initial tension and slope have been set properly, and the slitting machine will automatically adjust the tension of unwinding and rewinding according to the change of the roll diameter of the unwinding material and the rewinding material. The cost of this tension control method is slightly lower than the previous one, and it is mostly used in slitting machines for materials that have skipped changes in the unwinding tension of raw materials (such as adhesive tape) and materials that do not require high tension control accuracy.