Rosti - Injection Blow Moulding

Injection Blow Moulding

Injection blow moulding presents valuable opportunities for your manufacturing project. Rosti’s continual investment in this innovative technology has already enabled us to provide our customers with injection blow moulding as a well-established method for producing single-use bottles, but Rosti’s continuous investment and research in this area means that we now also use this technique in innovative ways to make lighting products and heavy-duty alternatives to glass. Whatever your needs, consult us to see whether injection moulding is your perfect manufacturing solution.

Get in touch
Rosti - John Kidd
John Kidd

Regional Technical Director Asia
E-mail: rosti@rosti.com

Rosti - Tony Austin
Tony Austin

European Technical Director
E-mail: sales@rosti.com

How does injection blow moulding work?

Injection blow moulding with Rosti lets you mass-produce hollow items in large volumes, cost-effectively with little waste.

It is a technique that is easy to understand, but difficult to master. Injection blow moulding comprises of key steps in a process that produces a seamless finished product. It first involves shaping the elastomer into a pre-form – this is essentially a tube of resin that will expand to become the finished product. The pre-form is inserted into the mould, and compressed air is then blown into it. Once it is fully expanded, the mould is opened and the moulded item is ejected.

The item is formed by being pressed against the inside of mould. That means that with careful toolmaking, we can give your product a beautiful, smooth finish without additional processing.

Injection blow moulding in more detail

1. Injection 

The machine for making the blow-moulded parts is comprised of an extruder barrel and the screw assembly. This produces the molten material that feeds through into the mould, which is designed to produce the final shape of the part or product. 

2. Blowing

The core rod rotates as the mould is opened up and it releases compressed air inside the mould, which then expands to produce the final shape of the hollow part. 

3. Ejection

The mould cools. It then opens and the core rod moves to the ejector point. The core rod is removed and the part is tested for leaks. The process includes more than one core rod so that the injection and blow moulding procedure can be completed simultaneously.

What are the advantages of blow moulding?

When working on any project, cost is a strong consideration. But it is especially critical when working at a large scale and in industrial applications. Injection blow moulding tends to be less expensive when compared to other methods that offer similar properties. It is also a highly customizable process, making it easily adaptable to different scales. Rosti works with clients on large and small projects around the world. 

Injection blow moulding is ideal for improving the consistency of the product quality and provides a stable and easily adjusted base for making parts. 

This technique is also extremely fast. Injection blow moulding is attractive for those looking for a rapid manufacturing solution. The procedure produces exceptionally large quantities of your product, with a rapid turnaround time. And you can run the process indefinitely. 

Plus, injection blow moulding is versatile. There are hundreds of potential uses for products manufactured using this technique, and more are being discovered every day.

History of injection blow moulding

This versatile technique has not been around forever. It is thanks to the foresight of a group of manufacturers in the 1930s that we can rely on the technology as we know it today. Plastic blow moulding was “invented” by Ferngren and Kopitke, a pair of inventors that discovered a new way to use the ideas inherent in glass blowing within plastics. The technique continued to develop during the coming decades, although it was not widely used since plastics were not in wide circulation. 

In the 70s, plastic blow moulding accelerated, with the rapidly increasing use of plastics in most industries. But it was the birth of the drinks bottle that revealed the full advantages of this technical method. Injection blow moulding could quickly produce the different sizes required for soda servings and the manufacturing process accelerated to keep pace with demand. 

Today, injection blow moulding produces bottles but it is also used for other purposes, including cosmetics packaging, dairy packaging, jars, and drums, as well as other parts made from plastic.

How Rosti have pushed the boundaries of injection blow moulding

Since its invention, as you can see above, this technique has mostly been used to make single-use plastic bottles. Rosti have been at the forefront of new production methods and uses and have been adapting and refining our injection blow moulding technique for many years. As a result, our methodology is reliable and versatile.

For instance, we can create bottles with varying thickness. This could be useful if you want to produce bottles that are thicker around the neck, to ensure that the neck is not a weak spot. Alternatively, you might need your bottles to have a heavier bottom, or to have greater tensile and burst strengths to contain carbonated drinks. We have a proven track record in innovative requirements and purposes for injection blow moulding and can help you whatever your plastics needs. 

Beyond this, we have made innovative use of different materials and resins. We have developed the mass-production of glass-like, thick-walled transparent plastics for use in reusable water bottles and lighting products. Through the controlled blowing of partially hardened plastic, we can manufacture attractive products with different colour and transparency.

Our injection blow moulding capabilities are continually expanding and we help you take your projects to the next level.

Finding the right method for you

Above all, Rosti prides itself on leading our customers from concept to reality. We use our years of experience to advise you of the right material, thickness, shape, and tool design to meet your needs. Injection blow moulding is a complex process and not for everyone, but it has critical advantages when used in the right way. 

We are available throughout the entire process, to make sure that you get the right end-product for your needs and goals.

It is possible that we will discover during the design process that another moulding technique would be better for your project. That is one of the benefits of working with a partner with such a wide range of knowledge, experience and capabilities – by seeing the big picture we can help you to create your product in the most efficient way possible.

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