In the production of plastic bags, rewinding is one of the key links in the film blowing process, which directly affects the flatness, thickness uniformity of the film material, and the smooth progress of subsequent printing and bag making. The following are the main precautions during the rewinding process:

1. Stable tension control
Excessive tension: It will cause the film material to be stretched and deformed, uneven thickness, and even wrinkled during rewinding.
Too little tension: It will cause the film material to be loose, the rewinding is not tight, and it is easy to bubble or slip.
It is recommended to use an automatic tension control system to achieve constant tension operation.

2. Keep the film material fully cooled before rewinding
If the film material is not completely cooled and shaped, it is easy to cause adhesion, wrinkles, deformation and other problems during rewinding.
It is recommended to strengthen the cooling effect of the air ring or extend the rising distance of the film material to make it fully cooled.

3. The edges of the rewinding should be neat
Untidy rewinding on both sides will affect the subsequent printing positioning and slitting.
It can be equipped with an automatic deviation correction system (EPC) to prevent the film cylinder from swinging left and right and ensure that the edges are neat.

4. Adjust the appropriate winding speed
The film blowing speed and winding speed must be coordinated. Winding too fast will pull the film material, and winding too slowly will backlog and wrinkle. Generally, it should match the extrusion volume to avoid "film extraction" or "film stacking".

5. Match the winding pressure with the type of film
LDPE film is soft and requires moderate winding pressure; HDPE film is harder and needs to increase the winding tension appropriately. For composite film, thick film, and smooth film, the pressure of the pressure roller needs to be adjusted specifically.

6. Prevent static electricity accumulation
Friction during film blowing can easily generate static electricity, which will cause problems such as film adsorption, adhesion, and foreign matter adsorption. It is recommended to install an electrostatic eliminator in the winding section.

7. Pay attention to the selection and installation of the winding shaft
The winding shaft should be smooth, concentric, and cannot be bent.
The core paper tube needs to match the width of the film to avoid skew and wrinkling of the film material.

8. Environmental cleaning and temperature and humidity control
Avoid dust or impurities in the air from being adsorbed on the film surface, affecting transparency and printing quality.
Control the ambient temperature to prevent thermal shrinkage of the film material or bubbling of the roll material.

A good winding process should meet the following requirements:
The film roll is tight and not loose
The edges are neat and not deviated
The thickness is consistent and there is no film pulling
The roll surface is smooth without bubbles or wrinkles