Injection Molding : What it is, How it works [2023]

What is an injection molding machine and how does a plastic injection molding machine work? These two queries are widely asked or searched about the plastic injection molding machine.

To understand how plastic injection molding machines work you should first understand/know what the injection molding process or machine is.

So let’s understand the above mentioned injection molding terms from scratch!

What is plastic injection molding?

what is Injection molding machine

Injection molding is a one of the plastic products manufacturing process from the plastic granules/powder form material.

 In Plastic injection molding process basically plastic material is molten by giving heat then it forwarded into the closed mold where material takes shape of product inside closed mold then cooled properly thereafter mold opened and ejected the final shaped product.

Large number of identical complicated pieces production/manufacturing is possible within a short time period.

Whether you want to manufacture small or large quantities of identical shape products/parts then injection molding is the best process (But keep in mind that for every plastic product you may have seen so far are not injection molded so only this process can be used for certain shape products.)

Injection molding machines are electrical, Hydraulic available.

How does an injection molding machine work?

To explain how the injection molding works, I have simplified this process by breaking it down into steps.

But before getting into steps you should know this. 

Injection molding has three zones : Feed zone, Transition zone, Metering zone. 

Now let’s understand step by step so In Plastic injection molding process happens in five steps: Feeding raw material, Heating & Melting, molding, cooling, ejection of final products.

First raw material is fed through hopper which located at the top of injection molding machine in feed zone then feeded material comes at the bottom of feed zone then it forwarded to transition zone and in transition zone consists the barrel, heaters above barrel, and reciprocating screw so in transition zone material is melt due to high temperature and then melted material forwarded by rotating reciprocating screw through nozzle into the mold.

Once material is filled into closed mold for a while (cycle time will depend upon shape or product)it is kept inside and then it also cooled inside closed mold once it cooled mold opens to eject the part/product.


 Are injection molding machines electrical or hydraulic?

Yes Injection molding machine both type available electrical as well as hydraulic. Injection molding selected by considering several factors.

In which form is plastic processed in injection molding?

Usually plastic raw material or resin comes in two forms: granules and powder. The best thing is granules and powder in both forms plastic material can be processed.

Where is the hopper located?

Hopper is located at the top of the injection molding in the feed section.


I hope you enjoyed reading about what injection molding is and how an injection molding machine works. If you have any other query or suggestion then feel free to comment in the comment section below.

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