What Is the Plastic Manufacturing Process?

V. Saxena

The plastic manufacturing process refers to the series of steps required to turn raw oil and natural gas into plastic products, such as cups, hoses, pipes, and straws. It is a very complicated process that first begins with transforming oil and natural gas into hydrocarbon monomers that are then linked together into long chains known as polymer plastics. Based on the type of monomers linked together, the process can produce a variety of different types of polymer plastics, such as polyethylene terephthalate (PET), high density polyethylene (HDPE), and polyvinyl chloride (PVC).

The plastic manufacturing process is what turns raw oil and natural gas into plastic products.
The plastic manufacturing process is what turns raw oil and natural gas into plastic products.

Once these plastic polymers have been created, the next step in the process is to transform these simple polymers into complex consumer products. The four sub-processes that may be used to do this are injection molding, extrusion molding, blow molding, and rotational molding. Each process produces a different type of plastic product.

PVC pipe fittings.
PVC pipe fittings.

Injection molding is a plastic manufacturing process wherein plastic polymers that have been compressed into plastic pellets are fed into an injection molding machine. These machines mold the pellets into the correct shape and add additives to give them the correct color and texture. This process produces plastic products such as butter tubs, yogurt containers, closures, and fittings.

A plastic toy with with multiple injection-molded parts.
A plastic toy with with multiple injection-molded parts.

Extrusion molding is practically the same as injection molding, in that it molds plastic pellets into shapes. The difference is that this process also uses a shaped die to give the plastic mold a tube like shape. As such, this plastic manufacturing process is used to create pipes, tubes, and wire insulation.

A plastic bag.
A plastic bag.

Blow molding is a more complicated process that is used to create hollow plastic products with an opening or neck. The two types of blow molding are injection blow molding and extrusion blow molding. Both processes involving turning plastic pellets into molds and then injecting air into the molds to make them hollow. The difference is that injection blow molding can only produce small containers, whereas extrusion blow molding isn’t limited by size.

The fourth plastic manufacturing process, rotational molding, is the most complicated and expensive. Like the other processes, it turns plastic pellets into a mold. The difference is that the mold is then rotated to create complex hollow shapes. Where rotational molding differs from blow molding is that the hollow products it produces are entirely closed, and they do not have an opening. Such products include plastic toys and furniture.

During the manufacturing process plastic pellets are melted and molded.
During the manufacturing process plastic pellets are melted and molded.

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Discussion Comments


The big business of plastic products manufacturing and how to recycle the unwanted products is an important issue.

In addition, the plastic bottle manufacturer and all of us consumers has a great responsibility to get these bottles recycled.

I know that some methods have been developed to recycle some types of plastic products, but there are other kinds of plastic that, at this time, are not able to be recycled. I wonder how well the recyclable products break down and is the quality of the new plastic as good as the original?

Plastic bottles are a huge problem. Some gracious people do put them into recycling bins. But so many just toss them wherever they are when they're done with them. The beaches, forests and trash cans are full of them. They will sit for eons before they start to break-down.

I've heard that even when plastic bottles are recycled, the new bottles are thinner and collapse when held.


The use of oil is used in the process of manufacturing plastics. I know we wouldn't have all the products that we have, if more items were made of other materials. But still, what is to become of our oil reserves if we continue on this path.

I don't know just how much oil it takes to make plastics. But when I think of all the plastics there are in our environment, it must be quite a bit.

When I just look around my house and yard, I'm amazed at how many items are made from plastics.

I guess plastic is here to stay. But I would like to have more items made from wood, even if they are old and need re-doing.


When I think about the number of plastic water bottles that are used at a sporting event, amusement park or concert, the thought can be overwhelming.

It makes you wonder if plastic bottle manufacturers have any idea of the number of bottles that are thrown in the landfill, as opposed to those that are recycled.


When you become aware of how many plastic manufacturing companies there are, and all the steps that are taken for this process to take place, it makes you appreciate all the plastic recycling efforts.

A lot of time, money and resources go in to making plastic products, and it makes so much sense to recycle and reuse these plastic items as often as possible.

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