Simple Guide To Plastic Molding 2024

Plastic has been the most used material for almost a century. Due to its characteristics, price and the possibilities it provides, we find plastic everywhere. From water bottles to car parts, it is literally everywhere around us. Also, we are all accustomed to the fact that if we need a product made of this material, we can very easily order and get exactly what we wanted, which is certainly not possible with other materials. But we believe that you have not thought about the process that needs to happen in order for you to get the desired product. To explain how it all works, below you will read a simple guide to plastic molding.

What exactly is that?

At the beginning let us first explain to you the general concept of plastic molding. It is the conversion of raw, molten material into a product. This is done by pouring the molten plastic into a mold that has the desired shape. Then the required temperature and pressure are applied until the product completely takes the shape of a mold and then all that remains is to cool down. There are various types of how this is done, and we will write about it later in the text, so you will gain a complete insight into the whole process.

How did it all start?

Throughout the eighteenth and nineteenth centuries, billiard balls were made of ivory. We all know how expensive ivory is and how it is obtained in a very cruel way. And for the purpose of billiard balls, it was not very effective, so people turned to the famous American inventor John Wesley Hyatt. Their request was that he devised a new material for the production of billiard balls, of higher efficiency and to be cheaper. He found celluloid, which became a material that completely replaced ivory, except for the purpose of making jewelry and revolutionized many industries. A few years later, John Wesley Hyatt, who had over a hundred patents in addition to this one, devised the first injection molding machine. It was a very basic machine compared to today’s and worked on the principle of a hypodermic needle. However, with its advent, plastic became even more prevalent and many products began to be made from it. To this day, many new types are being found and it is used in all industries, as we have already said.

The most common manufacturing processes

1. Compression molding

img source:

One of the simplest methods is to heat the plastic and put it in a mold. Compression achieves exactly the look you want. The product created in this way will be very strong due to the process of heating and compression. It is most often used in the automotive industry, because in this way parts are obtained at a much lower price than those made of metal, and they last a very long time. However, this is a more expensive process compared to others, so mostly only large companies use it. If you notice that we said that parts are cheap and the process is expensive, we say that because of the investment at the beginning, which is big.

2. Injection molding

img source:

This has become the most used process by far. It enables the production of a large number of products, of very good quality and at affordable prices. It is clear to you that this is a bullseye for any company. The resin goes through five parts of processing until you get the final product. A lot of products can be produced in a short time using this method. Due to the way the whole process takes place, it is very easy to increase production as needed. If a large order arrives, you will not have to enter new equipment but will be able to with the existing one. And the higher the production, the lower the costs. Check this for even more information on the injection process.

3. Rotational Molding

img source:

This method has many advantages, the biggest of which is that the material does not waste at all during processing. A large rotation creates a centrifugal force and thus makes products that are hollow. Eventually, it is just taken out of the mold when it has cooled. When you need something hollow, this is a safe choice.

4. Thermoforming

img source:

You cannot start production immediately using this technique, as it will take several weeks before the thermoforming mold is ready for use. The process takes place by first heating the material and then creating the desired shape and finally finishing to correct potential irregularities.

5. Blow molding

img source:

To most easily understand how this works, we will compare it to glass blowing because the process is very similar. First, the plastic is heated, and then hot air is added. This is followed by cooling. In the end, hollow products are obtained, and also due to the way of processing, the walls are thin. That’s why it’s ideal for making bottles and things like that.

6. Extrusion Molding

img source:

This is most different from all the others we have changed because there is no mold, but die processes the product and gives it its final shape. Very useful for making things like pipes and is not an expensive method, but there is a very limited number of different things that can be made this way.

The most common mistakes

The most common mistake people make is to think that they can do everything themselves and not master the necessary skill, as well as that all employees do not have the necessary skill. When starting this business, it is normal for a mistake to happen, but it must be limited to as few as possible. There are many common mistakes that will be detrimental to a company’s budget. But if you properly research all the methods and decide on exactly the one you need, and then learn the skills, there will be no problem.


This simple guide introduces you to the world of plastic processing and introduces you to some of the endless possibilities they offer. It is up to you to be further informed after the initial knowledge you have gained by reading this text.