The plastic material is first melted in a heating cylinder of the injection molding machine, and then a method of forming the melt by a reciprocating screw to push the melt into a cavity of the closed mold.
It can not only produce high-precision, high-quality products under high productivity, but also has many varieties of plastics that can be processed. The output is large (about 1/3 of the total amount of plastics) and the use is wide. Therefore, injection molding is important in plastic processing. One of the molding methods.
2. Extrusion molding
Extrusion is a method in which a plastic is continuously passed through a die in a flowing state by heating and pressurizing in an extruder.
It is generally used for the forming of sheet, pipe, monofilament, flat wire, film, wire and cable, etc. It has wide application and high output. Therefore, it is one of the important molding methods in plastics.
3. Foam molding
It refers to the addition of a suitable foaming agent to the foaming material to produce a porous or foamed product. The foamed product has the advantages of low relative density, high specific strength, low raw material dosage, sound insulation and heat insulation, and foaming material. There are PVC, PE and PS.
Products include: film, sheet, pipe, and profiles. Foaming can be divided into chemical foaming and physical foaming.