Difference between Blow Moulding and Injection Moulding

by Naman A. Well-Motivated Digital Marketer

Today, the demand for plastic products has skyrocketed and parallel to this demand, the plastic industry has been growing exponentially over the course of the years. 

To make this production more convenient and efficient, certain innovations took place and with them came into being different plastic processing machinery which today have become the backbone of this industry. 

Two prominent ones amongst these are blow moulding machines and injection moulding machines, which while following different procedures and producing different kinds of products are key to the working of this said industry. 

So, today let’s decipher the working of the plastic industry and have a look at what exactly blow moulding and injection moulding is and what is the difference between the two.

What is Blow Moulding?

Within the plastic manufacturing industry, blow moulding is a process using which hollow objects of plastic are made. The products made using a blow moulding machine include your everyday plastic items like shampoo bottles, milk and water bottles, plastic drums and automotive parts like air ducts. So, everything which is hollow and made of plastic is manufactured using the blow moulding technique.

Basic steps of Blow Moulding.

1. Through a screw or hopper, depending on the machine, plastic pellets are inserted into the blow moulding machine.
2. These pellets are then heated to their melting point within these machines and are converted into a tube-shaped object, called a parison.
3. Then compressed air is pushed into the parison, where it inflates and takes the desired shape.
4. When cooled down, the product is taken out and undergoes various labelling and decoration processes to become the products that you see around every day.

 

What are the advantages of Blow Moulding?

 

1. Without the blow moulding machine, the plastic manufacturing industry would be left lifeless. With them are produced every plastic container that you use in your household or workspace.
2. Of all the plastic processing machinery, blow moulding machines are the most economic and cost-effective. Also, as it’s a one-step process, you can reduce your labour costs.
3. With blow moulding, you can engage in the mass production of diverse products in a limited time frame.
4. Blow moulding machines allow the use of not one but many techniques and use different materials including Acrylonitrile Butadiene Styrene (ABS), High-Density Polyethylene (HDPE), Low-Density Polyethylene (LDPE), K-Resin Styrene-Butadiene Copolymer (K-Resin SBC), etc.

What is Injection moulding?

Unlike blow moulding machines using which hollow objects of plastic are made, injection moulding machines are used to create solid objects of plastic. The products created using this process include but are not limited to electrical knobs and fixtures, disposal bins, toys, roofing vents, wire ties and storage racks. In injection moulding also the plastic pellets are heated to reach their melting point to increase their malleability. The production cycle includes four processes namely, clamping, injection, cooling and ejection.

Basic Steps of Injection Moulding

1. Pellets are inserted into the barrel through the hopper of the injection moulding machine.
2. The screw rotates, creating friction and this friction melts the pellets.
3. Then this melted material is pushed into the tool cavity where it cools down. Here, it’s important that all the air passes through the vents, otherwise, it could hinder the production process.
4. Once the product reaches its ideal ejection temperature, it is pushed out through the tool opening.

 

What are the advantages of Injection moulding?

 

1. The high pressure involved in injection moulding allows greater flexibility in terms of design.
2. Injection moulding machines allow the use of fillers and these fillers could be used to enhance the durability and strength of the products.
3. Using the co-injection technique, different types of plastic could be used simultaneously without worrying about the result.
4. Being an automated process, you can save up a lot on your manufacturing costs.

What are the major differences between Blow moulding and Injection Moulding?

 

While both blow moulding machines and injection moulding machines are two prominently used plastic processing machinery, they are not interchangeable. To understand this let’s have a look at the major difference between the two.

1.   The kind of products produced.

The basic difference between blow moulding and injection moulding is the kind of products produced. As mentioned before, blow moulding machines are used to produce hollow plastic containers whereas injection moulding is used to produce solid plastic products.

2.   The role of air.

Another major difference between injection moulding and blow moulding lies in the technique itself. In blow moulding, air plays an integral part in the expansion of the product but when it comes to injection moulding, air can hinder the entire process. In injection moulding, all the air needs to be released through the vents to ensure that no bubbles or air pockets are formed within the product.

So, this is all that you need to know about blow moulding and injection moulding, including the steps involved, advantages and major differences. Our experts at Mitchell Industries specialize in both these techniques and can help you through the entire process. If you are looking for any related services, you can contact our experts and they would be happy to help you out.

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Created on Nov 22nd 2021 19:29. Viewed 349 times.

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