The document discusses various plastic film manufacturing processes. It describes three primary molding processes: injection molding where plastic is heated and injected into a mold; extrusion where plastic is pressed through a die to form sheets and other profiles; and blow molding where plastic is blown to form hollow shapes. It then briefly mentions additional secondary molding processes like thermoforming, compression molding, calendering, pultrusion, vacuum forming, and rotational molding.

1. Plastic film manufacturing process
As a polymer, plastic has now become one of the most widely used
materials for human beings. Because of its flexible molding process, it is
widely used in various fields. Generally speaking, the most common
plastic molding processes are injection molding, extrusion molding and
blow molding. But when it comes to secondary molding, three moldings
are even more.
1. Injection molding
The main method of processing plastics is injection molding. In this
process, the plastic is placed in a hopper, then heating and injects the
plastic, which is pushed through a long chamber with a reciprocating
screw. It is then softened into fluid state. The nozzle is located at the end
of the chamber, and the fluid plastic is forcedly cooled through the nozzle,
close the mold. When the plastic is cooled and solidified, the
semi-finished plastic product is ejected from the press.

2. 2. Extrusion

3. The extrusion process is usually used to make films, sheets, tubes,
profiles, rods, jacket wires, filaments, wires, and cables. With the
injection molding machine, the dry plastic is placed in a hopper and fed
into a long heating chamber. At the end of the chamber, the material is
pressed out with a small opening, or in the shape of the desired end
product mold. After the plastic leaves the mold, it is placed on a conveyor
belt and cooled. Blower is sometimes used during this process to help
cool it down.
3. Blow molding
4. Thermoforming
The sheet is clamped on the frame and heated into softened state, and it is
brought into close contact with the mold surface under the action of an

4. external force to obtain a shape similar to the mold surface. After cooling
and shaping, the product is finished after trimming. This process is also
used in rubber processing.
5. Compression Molding
6. Calendering

5. 7. Pultrusion
8. Vacuum Forming

6. 9. Rotational Molding