What is the difference between injection molding and extrusion blow molding

Everyday we use blow-molded products, however, we hardly know anything about blow molding. The plastic industry is one of the largest industries in the world. Plastic makes life easy by producing cost-effective products and options.

While working in the plastic molding industry, you need to know the exact difference between injection molding and extrusion blow molding to use these processes correctly at the right time. So, here is some information on both these terms to make the concepts clear for you:

Blow molding is used to manufacture plastic products. Any hollow plastic container can be made with blow molding. There are a few different types of blow molding processes. The difference in the processes is caused due to the size of the parison, how they form the parison or how the parison moves between the molds.

Extrusion Blow Molding (EBM)
• Injection Blow Systems (IBS)
• Injection Stretch Blow Molding (ISBM)

These are the three main types of blow molding processes.

What is Extrusion Blow Molding?

In extrusion blow molding, the manufacturers melt the plastic and extrude it into a hollow tube, which is commonly known as a parison. Then this hollow tube is placed inside a cooled metal mold and the air is blown into it to give it the shape of the mold. Once the plastic cools down, the mold is opened and the newly formed plastic product is taken out.

It is one of the methods that is highly used for the formation of plastic products. You can use different types of plastic in this method for the molding process. It is safe and the best method to be used in China in the plastic industry.

Some advantages of extrusion blow molding include

Now, when you are using this method, you need to know about its different advantages so that you can use it to the fullest. So, here are some of the benefits of extrusion blow molding:

1. EBM blow molding needs lower pressure, hence the cost of machinery is very less compared to other processes. It is one of the most cost-effective and best technologies available today. EBM machines also reduce labor cost and the cost of producing plastic products is also less.

2. Mass production of plastic goods quickly and efficiently is possible with extrusion blow molding. It is faster and provides higher volume outputs within time.

3. The extrusion blow molding is a versatile method that can be used in a variety of unique applications such as fuel tanks, flower pots, vehicle seal support, plastic containers, etc.

4. Being an automated method, it helps in the formation of a precise receptacle and so, very little flash is produced around the material.

5. This method helps in achieving seamless part incorporation. Along with this, it is capable of molding complex parts and can incorporate the handles.
There are various other benefits of this method, which varies from one manufacturer to the other.

What is Injection Molding?

An injection blowing molding process is utilized in the production of hollow objects in large quantities.

In injection molding, the polymer is injection molded upon a core pin and then this core pin is rotated to a blow molding station to inflate and cool it down completely. It is the method of blow molding that is least used out of the three.

In the factory, this method is used for the production of small medical and single-serve bottles, such as syringes. It is a process that is divided into 3 steps- injection, blowing and ejection. And, each of these steps is required to be done carefully and perfectly to get the desired results of the products.

Some advantages of injection molding include

Before you start using an injection molding method, you need to be aware of all of its benefits that are mentioned below:

1. It is one of the highly-efficient methods for the production of plastic products. It is the method that helps in making the products at high speed. It is an extremely fast process that helps in producing high-volume of products. While we are talking about the speed of the process, you need to know that it varies from material to material.

2. It is having the capability of complex part designing. It can form millions of virtually identical parts. Using this method, you can make the right design of the products and get consistent and high-quality products.

3. With this method, you are going to get strong plastic products. It is known that the customers demand products with maximum strength, and this method is capable of making the products with the required strength.

4. It is a flexible method that can mold plastic of different types. It can make different products with different materials.

5. It is an automated process that helps in saving a lot of money and time. It saves you the cost of labor required in completing the task.

6. It is good to use this method, as it reduces waste. It is going to offer you a high-volume of production without creating too much waste to harm the environment.

So, you can use this method for the production of plastic to avail of these benefits.


As both of these methods are used for the production of plastic, there are a few differences between them:

1. The first difference is that both of the methods are used for making different types of products. While the extrusion blow molding process is creating 2-dimensional products, the injection blow molding process is used in creating 3-dimensional products in the final output.

2. The second difference is in the tool used in both methods. In the extrusion blow molding process, a die is used to get the final output and in the injection blow molding process, a mold is used to get the final product.

3. The production time also differs in both methods. The extrusion blow molding process is slower than the injection blow molding process.

4. Now, talking about the scrap or residue that is left behind is different in these methods. In the extrusion blow molding process, the scrap is with flash and trimming, while, in the injection blow molding process, the scrap is without flash and trimming.

5. At this point, we are going to talk about the part thickness of the machine used in both the process. In the extrusion one, the part thickness depends on the stretchability of the material during the process and, in the intrusion on, the part thickness relies upon the relationship between the core and the mold.

6. At the end, the extrusion blow molding process is seen as a pocket-friendly process in comparison to the injection molding process.

Looking at these differences, you need to choose these methods keeping your needs and their features in mind to get the desired results.

So, this is the information you need to know while working in the plastic mold industry. You need to be well aware of both these methods to get the desired products. Also, you can easily find the suppliers for the selling of the products made with these processes.

Blow Molding Machine Manufacturer

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