This article we will cover some things you need to know about blow molding. We will include the following:

  • What is blow molding

  • Types of blow molding

  • Advantages of blow molding

  • Products of blow molding

So first, let us read on to find out what exactly is blow molding.

What is Blow Molding

Blow molding is a form of manufacturing used to create plastic products. The process involves heating a plastic tube (known as a parison), and placing it inside of a mold. Then compressed air gets released into the tube. Expanding and inflating the plastic to take the shape of the mold. This mold is hollow inside and depending on the amount of plastic used it defines its thickness.

What is blow molding? This involves blowing plastic into a mold. We often see blow molding used to make plastic bottles. We blow melted plastic into plastic bottle mold. Then before you know it, we can see these popular blow molding products on store shelves!


There are actually two main types of blow molding. Both are quite similar in how they function, in that they both use a parison/tube. We can see more information on these below:

Extrusion blow molding – EBM involves melting plastic. This plastic is then extruded into a tube. Extrude meaning forcing or pushing something into. This is then expanded with compressed air, after which the product cools down. Usually, it is hollow products produced with this form of plastic blow molding. Think of containers or bottles. EBM is a common molding process in the manufacturing industry. As it can mass produce a large volume of objects with the same shape and sizes.

Injection blow molding – This blow molding process is like that of injection molding. Injection blow mold is when a heated material gets injected into a core pin. After which the pin rotates around a molding station. The heated material is then given time to inflate and then cool. While both types of blow molding get used, injection isn’t as common between the two. Injection blow molds are often considered for smaller, hollow objects.

Below we can see an image of an injection blow molding process. We can see the parison, between two blow moulds. The shape of the blow molders we can see is that of a plastic bottle. The molds surround the tube and the parison expands, completing the plastic product.

Blow Molding 101: Advantages

There are several advantages why some choose to blow mold parts. Let’s take a look at some of the main reasons why:

Price – One of the biggest benefits of blow molding is that of cost. Part of the reason for this is that blow molding involves fewer tools. But also the fact that the cost of the machinery is lower too, when compared to injection molding.

No assembly required – Blow molding works well for products which are one single piece. This cannot be possible in some of the other manufacturing techniques. This means that products do not need to get connected or assembled, they are complete and ready to go.

Reduced flash – Flash refers to the little pieces of plastic which bleed around the seams of a product. Flash can be troublesome, as it results in an extra step during the production process. That step is having to finish and sand off a part before it gets shipped. The blow moulding process results in little or no flash. Resulting in faster turnaround times for your blow molding parts!

Plastic blow molding was viable in the 1900s, but blow molding has been around for at least 2000 years! Its earliest stages were in the form of glass blow molding. Where smiths would blow into heated glass and mold the glass into different shapes. Nowadays we see plastic blow molds instead of glass. With blow molding manufacturing machines instead of smiths.


We use blow moulding equipment to make a wide variety of products. These products range from a large selection of different industries. From automotive to food packaging. With any hollow type of plastic product, chances are blow molding created it. Thanks to its inexpensive costs, easy mass production and quick turnaround times. Some of the products that are blow molded products include:

  • Barrels and barriers

  • Stadium seats

  • Fan housing

  • Coolers

  • Planters and watering Cans

  • Toys

  • Bottles

  • Mud guards

  • Fenders

  • Containers and cans

  • Hoses

  • Drums

Blowmolding equipment is incredible. We use the blow moulding process to create all kinds of amazing shapes and sizes. A blow molder machine can make something like a childs toy or an automobiles mud guards. To watering cans or the thousands of seats found in a football stadium!

Blow Molding 101: Conclusion

Today we have covered everything we need to know about blowmolding. Looked at the two main types of the blow mould process. Looked at the many blow molding products you can find today. Compared the advantages of blowing molds over other manufacturing techniques too.

Looking for one of the finest blow molding companies out there? Consider Prototype Finder. We here at Prototype Finder know a great deal about blow molded solutions. This is because we are a prototype manufacturing company! We have worked with blow injection molding many times. Along with using a wide variety of plastic bottle molds. We built blowing mold products as a manufacturer for many years.

Should your project include plastic bottle molding? Need an injection molder to help decide the best bottle molding technique? If you are not sure what to do next, contact us and request a quote! Or you can indeed ask us any questions and we will be more than happy to assist in any way we can!

If you enjoyed this article make sure you take a look at some of our other posts on many other materials and topics. Try Blow Molding vs Injection Molding to see how they compare. Or read everything about Overmolding. Then there is Titanium vs Aluminum. These and more are on our Blog.

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