Composition of traditional roll changing mechanism for blown film machine

With the increasing competition in the plastic industry, blown film machines are developing towards high speed and wide width. blown film machines also require the diameter of the film roll to be larger and the quality of the rolled film to be higher. With the development of pneumatic technology, high-speed automatic blown film machines can achieve a folding width of up to 2.1m, a speed of over 80m/min, a roll diameter of up to 1m, and a production capacity of 400kg/h for films with high roll quality. Traditional roll changing mechanisms are not only difficult to operate and require high physical labor intensity during the roll changing process, but also prone to generating waste when cutting into multiple films (more than 3 films on one side) or frequently changing small films. In order to solve the above problems, this article introduces how to use PLC to control the roll changing mechanism of high-speed blown film machine and achieve automatic roll changing.

The composition of traditional roll changing mechanism:
The traditional roll changing mechanism of the blown film machine consists of a lower turntable device, a length counting device, a dual station winding machine, etc.
The turntable device is located on the winding rubber roller, which is shaken by the winding handle and driven by a chain to flip the turntable bracket and mechanical arm.
The length counting device receives signals from the proximity switch and transmits them to the counter, counting once per meter. The length of the film is pre-set, and when the winding reaches the set length, the alarm bell and light will sound.
The dual station rewinding machine consists of A rewinding and B rewinding, adopting a passive rewinding form. It uses the frictional force between the rolling large rubber roller and the rewinding roller to wind the film under constant tension.
A. The drive of the B winding rubber roller is controlled by two vector frequency converters to drive the deceleration motor separately. A. The speed of the B winding rubber roller is the same, and the direction is opposite, so as to achieve the goal of synchronous winding on both sides at the same time. A. The winding speed and tension of the B winding rubber roller can be adjusted separately without affecting each other, thus achieving the best winding effect. This rewinding system adopts passive rewinding, and the quality of rewinding largely depends on the curved surface trajectory of the guide rail where the rewinding inflation axis is located.
The traditional roll changing process: When the diameter of the roll reaches the required level, the roll is changed by moving the pre inflation roller above the rubber roller (preparation station), manually separating the film, moving the film roll to the bow shaped tail of the fish belly plate, and then shaking the roll changing handle. The newly replaced winding inflation shaft slowly moves to the winding station, and the roll changing is completed.
The drawbacks of traditional roll changing mechanisms:
1. During the roll changing process, the physical labor intensity is high: when the roll is full, an alarm is triggered. One person shakes the roll changing handle to move the inflation shaft on the turntable to the waiting area, while two people simultaneously move the full roll to the rewinding area and manually cut off the film. The entire process requires the cooperation of three people.
2. When cutting into multiple films (more than 3 films on one side) or changing rolls of small films, more people need to cooperate to complete it. Inexperienced cooperation or improper operation can easily generate waste.
How to solve the above problems
Manual roll change to automatic roll change: On the basis of traditional roll change mechanisms, an automatic roll change mechanism integrating functions such as automatic winding, automatic cutting, and automatic feeding has been added.
Transformation of automatic roll changing system:
Automatic rewinding: On the basis of manual rewinding, the rewinding handle is removed, and a deceleration motor is modified on it to be controlled by PLC as a flipping power source.
Automatic cutting: Add a cutting cylinder (rodless cylinder) on the flipping frame, and the cylinder shaft is connected to a precision pressure reducing valve, shuttle valve, air lock valve, pilot operated one-way valve, flow valve and other control components to form an air path. The air force is used to push the flying knife on the rodless cylinder shaft to perform reciprocating cutting motion; At the same time, add a magnetic cylinder on each side to control the pneumatic circuit of the rodless cylinder.
Automatic winding: Add a magnetic cylinder and a robotic arm on each side of the winding rubber roller, connected by a shaft in pairs, and add a precision pressure reducing valve, shuttle valve, air lock valve, pilot operated one-way valve, flow valve and other control components to the air path. When the winding is full, the translation cylinder releases pressure, causing the translation cylinder to extend forward and push out the full roll to the winding area, which is locked by the mechanical lock. The rear translation cylinder retracts into place, and the translation cylinder maintains pressure.