The square bottom valve bag making machine can be used to make valve pockets of various materials such as paper valve pockets, plastic woven heat sealing valve pockets, multi-layer kraft paper bag making machines, etc. The gluing process is used for bonding to present a square shape. The heat sealing process and principle of the square bottom valve bag making machine.
Heat sealing process and principle of square bottom valve bag making machine
1. Heat sealing knife gap
The gap of the heat-sealing knife refers to the pressure interval from which the predetermined heat-sealing pressure is transmitted to the heat-sealing surface when the upper heat-sealing knife contacts the bottom plate. Usually the gap of the heat sealing knife is set at 1.0 ~ 1.5mm, which is related to the bag making speed, film thickness, transfer function, etc. At the same film thickness and the same heat sealing speed, the heat sealing time of the heat sealing knife is relatively small, and the heat sealing strength of the product will decrease.
2. Heat sealing times
General heat sealing usually requires more than 2 times of heat sealing. After the bottom of the square bottom valve pocket is formed, there are generally at most eight layers. Usually, there are 5 sets of transverse heat sealing equipment for the square bottom valve pocket. Ultrasonic welding is used for heat sealing of zippers. Nice bag. The heat sealing strength is not easy to form in the center of the base material, and it is easy to cause a root break phenomenon if it is heat sealed too many times.
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