Industry NewsWelcome to PPD Film Rewinder Machinery

1. Changes in the unwinding tension If the tension in cling film changes, it will cause changes in its elongation, and the registration of multi-color printing must be affected. If the tension is too large or too small, it may even cause the printed plastic wrap material to break or fail to operate normally.

Caused by the changes in the tension of the printing materials, the speed of the machine, the non-uniformity of the tensile properties of the material, the irregular shape of the roll, and eccentricity. The tension changes caused by these reasons are irregular.

When the speed of the plastic wrap rewinding machine and the rewinding film rewinding machine are constant, it is assumed that the braking torque acting on the reel is constant. When the diameter of the reel gradually decreases, the roll tension of the printing material must increase gradually. . Although the braking torque can be adjusted and changed, whether it is manual or automatic adjustment, it is always performed after the change of tension is measured. Therefore, the change of unwinding tension always exists.

2. Detection of tension change In the popular plastic wrap rewinding machine and stretch film rewinding machine, the operator has found that the tension of the unwinding coil is changed visually and sensibly, and the friction brake is manually adjusted to restore the proper tension value. Manual adjustment can only control the tension roughly, and the adjustment operation is frequent, which is a backward adjustment method. In the unwinding tension automatic control system, a floating roller mechanism is generally used to detect the tension change. The floating roller is a guide roller whose axis can be translated up and down, and the bearing seats at both ends thereof are installed in the sliding track or guide groove. As for the coil is not round, the tension change caused by the unequal tensile properties of the material is rapidly alternating, and the position of the floating roller cannot be changed up and down by changing the tension, and the length of the tape can be lengthened or shortened. If the tension becomes larger, the floating roller moves down, and the printing material between the floating roller and the two adjacent rollers is released, so that the tension can be reduced. In other words, the displacement of the floating roller can change the length of the tape and absorb the rapid disturbance of the tension. Of course, the amount of displacement of the floating roller should be large enough, otherwise the automatic device will be frequently adjusted forward and backward, instead making the tension unstable.