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Different Methods for Manufacturing Plastic Products

These different methods for manufacturing plastic products give you a clearer outlook on how to approach your plastic manufacturing project. They are options to choose from on which methods your products need.


Plastic products are part of our daily lives and they can be seen everywhere from our homes, offices, parks, malls etc. Even though plastic objects are everywhere in our environment, a lot of people do not really know how these products get manufactured. The plastic industry is a complex one but it is much better to add up to our stock knowledge. In this article, let us discover the 7 different methods for manufacturing plastic products and you can also check out other industry related topics here.

Process of manufacturing plastic products.

7 Plastic Manufacturing Methods

1. Plastic Injection Molding

Plastic injection molding is accountable for more than 75% of plastic products we see out there today and is the most popular way of manufacturing plastic products. It is the process of using molds or die made out of aluminum or stainless steel to create plastic. The mold consists of a cavity side and core side and is placed into the injection molding machine. Plastic material is molten and injected into the empty cavity of the mold. Under great hydraulic pressure, the plastic part is ejected out of the mold once it cooled and hardened. The plastic injection molding method is hugely popular among manufacturing companies because of its capability to produce thousands of plastic parts at once.

2. Rotational Molding (Roto)

Rotational molding or commonly known as roto molding is a plastic manufacturing method which also uses mold with a core and cavity side but follows a different process compared to injection molding. Plastic material is poured into the empty cavity and heated inside an oven. The mold is constantly rotated by two axes while gravity makes sure the plastic remains on the tool walls to build up the right amount of thickness. The part is allowed to cool before the tool gets opened and have the part removed.

3. Injection Blow Molding

Plastic manufacturers use gas pressure to force molten plastic into the mold with injectiion blow molding. This method is commonly used to create plastic bottles. Plastic material used for this method are usually PET (polyethelene terephthalate) or PEEK (polyether-ether-ketone) due to their clarity and is known to be safe to use for consumables. Both types of plastic are also easy to recycle which is a plus for the companies who intend to use the plastic bottles.

4. Extrusion Blow Molding

Extrusion blow molding uses parison which is molten plastic in the form of a balloon and is placed into a dual-piece clam-type mold. Once the mold is sealed, the parison is inflated until it fills the empty cavity of the mold. The sides are water-cooled so the plastic quickly hardens and can easily be ejected. Extrusion blow molding is best used to create plastic cups, small or regular-sized plastic containers and plastic bottles.

5. Reaction Injection Molding (RMI)

This type of plastic manufacturing method is best used to produce rigid plastic parts. The automotive industry is the biggest gainer of the RMI method since it is commonly used to create plastic vehicle parts such as dashboards, bumpers, stepping boards etc. It uses thermosetting plastic which undergoes a chemical reaction inside the mold causing them to expand and fill the cavity of the mold. Once the chemical reaction is complete, the plastic part take its final form. RMI is relatively considered to be an expensive plastic manufacturing option due to the material and intensive labor involved.

6. Vacuum Casting

Vacuum casting is ideal to create numerous plastic parts without a big capital for tools and plastic material. A 3D prototype of the product is enough to jumpstart this plastic manufacturing process which is then placed into a sealed box filled with silicone or urethane. Once the 3D image model is removed, a cavity is formed and that can be filled with plastic resin to resemble the original model. Vacuum pressure is applied to take out air of the mold.  However, plastic parts made out of this aren’t durable and can degrade after a few production processes.

7. Thermoforming

This process is much like vacuum casting except plastic is placed over a die which is heated until it becomes pliable. The plastic material is stretched on the surface while vacuum pressure is constantly applied to pull the sheet down until it takes its final shape. This method can be done with a rudimentary approach and different products can be expected off of it but you cannot expect top quality results compared to the other methods mentioned beforehand.


The following plastic manufacturing methods mentioned above are the most commonly used by plastic factories while plastic injection molding rules them all. However, there are variations to the processes since some companies try to enhance or modify the methods in order to cut down on resources and expenses as well as improve plastic production lead time needed to produce top quality plastic. The different methods for manufacturing plastic products still remain true to its course and the descriptions above are still applicable to this point.

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