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A Comprehensive Guide to Injection Molded Plastic Packaging

Injection Molded Plastic Packaging

Among several techniques for molding plastics, injection molding is the most popular one. This technique has applications in multiple industries- food and beverages, household products, electronics, automotive parts, packaging, and many others. Regarding the packaging industry, the injection molding method is used to manufacture various molding packages for cosmetic products, household chemicals, food and beverages, PET bottles, and perfumes. Read further to know what injection molding consists of and the plastic packaging manufacturing process using this technique.

What an Injection Molding Consists?

Injection molding is used to create plastic packaging for several users in different forms. The injection technique is mainly used to manufacture the molding package, including containers and lids for packing food, packaging for household chemicals, bottles for perfumes and body care products, etc.

The injection molding technique involves injecting plasticized material into an injection mold, where this liquid material solidifies. Plastics in the form of granules are used during this process. This material can also use some other forms of processing, which use prepolymers and agents that polymerize during the injection molding process. This specific injection molding method is known as reaction injection molding (RIM).

Now that injection molders can be used for molding thermosetting and thermoplastic materials, they are important for manufacturing plastic packaging.

Injection Molded Plastic Packaging Manufacturing Stages

Below given is the injection molded plastic packaging manufacturing stages:

Heating and Melting Plastic 

In the first stage, the plastic material is heated and melted. The material is dosed from a container using a mainly designed screw revolving inside a cylinder, and then it’s heated using the heating elements. The plastic’s temperature increases due to friction on the cylinder walls. The rotational motion further distributes the heat evenly around the cylinder, and plastic is formed due to the high pressure within the screw.


The screw moves in rotational and reciprocating motion resulting in the molten plastic being injected into the injection mold.

Stabilizing the Plastic 

Once the plastic is poured into the form, it’s heated or cooled depending on its type. For instance, thermoplastic plastic requires cooling, and thermosetting plastics require heating. An appropriate method is used to stabilize the plastic, which helps maintain the mold’s shape when it cools down.

Creating and Polishing Packaging

The plastic mold is emptied via automatic ejection. The manufactured packaging is further cleaned of plastic residue that might have solidified in the feeding channels or on the parts connecting the mold’s two halves. This step is conducted mechanically – unnecessary elements are cut down, and the packaging is polished.


Different types of molding package that can be manufactured using the injection molding technique are plastic shipping containers, thin-walled injection packaging, injection molded boxes and jars, industrial packaging, etc. Along with packages, this technique also allows the manufacturing of closures for different types of packaging. Since injection molding has diverse applications in the packaging industry, it’s essential to install suitable machines and tools. Additionally, a manufacturer needs to figure out if it’s worth using a single-stage or double-stage injection molding method to create plastic packaging.