The film blowing machine is a device for heating and melting plastic particles and blowing them into a film, which is mainly composed of a blown film and a winding. The function of the winding part is to take up the blown film into a roll, and make the roll film smooth and wrinkle-free, the curling is neat, and the film on the reel should be tightly stretched to prevent the film from being stretched and deformed to ensure the quality. Therefore, constant tension control should be used when winding. At present, the torque motor is mainly used in the industry to realize the above control, but there is a need to manually adjust during the use process, the operation is inconvenient, the torque motor has high heat when running for a long time, the controller is easy to damage, and the reliability is not high. .