During the operation of the bottom sealing bag machine, the stability of film conveying is crucial to the quality of bag making. As a key part, the tension control system plays a role in ensuring that the film maintains appropriate tension during conveying and avoids problems such as relaxation or over-stretching.
The tension control system of the bottom sealing bag machine is usually composed of a tension sensor, a controller and an actuator. The tension sensor is responsible for real-time detection of the tension of the film, converting the tension signal into an electrical signal and transmitting it to the controller. The controller compares and analyzes the received signal with the preset tension value, and then issues a command to the actuator. The actuator is generally a motor or a brake, etc., which changes the tension of the film by adjusting its operating state.
The tension control system uses a feedback adjustment mechanism to achieve precise control of the film tension. When the tension sensor detects a change in the film tension, such as an increase or decrease in tension due to a change in the film roll diameter or an adjustment in the bag making speed, the sensor will quickly transmit the change signal to the controller. The controller calculates the amount of adjustment required for the actuator according to the preset control algorithm, and then controls the actuator to restore the film tension to the preset value. This feedback adjustment mechanism can respond to changes in tension in real time and ensure that the film maintains a stable tension throughout the entire conveying process.
In order to ensure the stability of film conveying, the tension control system of the bottom sealing bag machine usually adopts a constant tension control strategy. During the bag making process, no matter how the roll diameter of the film changes or how the bag making speed is adjusted, the system strives to keep the tension of the film constant. This is achieved by the controller automatically adjusting the output of the actuator according to different working conditions. For example, when the roll diameter of the film gradually decreases, in order to maintain constant tension, the controller will gradually reduce the speed of the motor and reduce the conveying speed of the film, thereby avoiding the increase in tension caused by the decrease in roll diameter.
In order to further improve the stability of film conveying, the tension control system will also set up damping and buffering devices. The damping device can suppress the vibration and jitter of the film during the conveying process and reduce the tension fluctuation caused by mechanical vibration and other factors. The buffer device can play a buffering role when the film is subjected to sudden tension or impact force, avoiding the film from breaking or wrinkling due to instantaneous tension changes. For example, buffer rollers are set at the feed end and discharge end of the film. When the tension of the film changes suddenly, the buffer rollers can absorb energy through a certain displacement to slow down the change rate of tension.
For some complex bottom sealing bag making processes, it may be necessary to control the film tension differently at different conveying stages, i.e., multi-stage tension control. For example, in the unwinding stage of the film, a larger tension is required to prevent the film from loosening; and when the film enters the heat sealing area, the tension needs to be appropriately reduced to prevent the film from overstretching and affecting the heat sealing quality. The tension control system achieves precise tension control of the film at each stage by setting tension sensors and corresponding control mechanisms at different positions, thereby ensuring the stability of film conveying and the quality of bag making during the entire bag making process.
The tension control system of the bottom sealing bag machine effectively ensures the stability of film conveying through the coordinated work of its components, using a variety of methods such as feedback adjustment mechanism, constant tension control strategy, damping and buffering design, and multi-stage tension control. This not only improves the quality and efficiency of bag making, but also reduces material waste and equipment failure caused by unstable film conveying, providing strong support for the stable operation and high-quality bag making of the bottom sealing bag machine.
