Faces of EUMEPS: Rainer Hormann, Pre-expander Pioneer at HIRSCH

As we delve into the intricacies of the EPS production process, Rainer Hormann stands out as a pivotal figure in the development of pre-expander technology. With decades of experience at HIRSCH, Rainer recounts his journey from an electrician to becoming a pre-eminent expert in the field. His insights shed light on the critical role of pre-expanders in EPS manufacturing and their evolution over the years. This interview explores Rainer’s profound knowledge and the innovative strides he has taken to optimise this essential equipment.

Rainer Hormann. Credit: HIRSCH.

Rainer, could you recount your career trajectory with HIRSCH and describe how you became the expert on Pre-expanders that you are today?

It all began on 1 February 1990, when I was hired as an electrician, primarily to build electric cabinets for HIRSCH machines. After a while, I started working on the external wiring of the machines. Once I had mastered this too, I was taught how to mechanically manufacture a “pre-expander”. Thanks to the expertise I had acquired, I was then also able to test the pre-expanders with raw material and prepare them for delivery.

The next step was to make a start-up. In 1994 I was finally sent to France alone for my first commissioning. As we started to build more and more pre-expanders and also added training and service assignments, I never really had time to concentrate on anything other than pre-expanders.

My knowledge was also helpful for sales support and development work. Today I can say that because of the insight I had into all areas, I was able to develop very well!

My know-how today is a collection of information over decades, especially a collection of failures. That’s exactly how I learnt what works and what doesn’t!

It was also always important to realise that the processing of EPS is not static and that you must adapt permanently. That’s why our pre-expanders were developed from the EPS converter’s point of view and not from the view of a machine manufacturer. That’s our most important USP which we gain every day from our own EPS processing plants in Europe.

It was also very important to work closely with our customers to find the right solutions and to incorporate their suggestions for further improvement. These then very often became a “must-have”.


Pre-expanders are central to the EPS production process—could you illuminate their significance and explain why proficiency in their operation is crucial?

As the pre-expander is the first step in EPS processing, there is a lot you can do right here to achieve the desired performance in the next steps. If you don’t do this, it can quickly become expensive!

For example, if the density tolerance is too high, this can lead to increased material consumption and subsequently to increased rejects. If the part weight is too high = loss; and if the parts are too light – complaints with return deliveries = loss. The desired parameters are then often not achieved in the quality control tests.


Considering your extended experience since 1990 – when you joined HIRSCH – how have advancements in pre-expander technology transformed the EPS industry?

The pre-expansion process and the steps are basically the same as in 1990.

However, by understanding the foaming process better and improving our ability to control and regulate the media, we have succeeded in optimising the use of raw materials and energy. Recording the data has also contributed a great deal to this. Whereas density tolerances of 3 – 5 % were normal in 1990, today we are talking about 1 % and even less under optimum conditions!


The pre-expanders, often dubbed the “Money-Expander,” are vital in our industry’s supply chain. Could you discuss their impact on productivity and efficiency?

The aim is to obtain the maximum output and best quality from the material used. Because if I waste money or produce bad quality at the beginning of the production chain, I won’t make up for it during the production cycle. Every end-product has certain defined properties. The first step is to obtain the right raw material. To get the perfect end-product, it is important to produce the specified density with minimal deviations.


In light of HIRSCH’s “HIRSCH:REuse initiative”, how do pre-expanders contribute to environmental sustainability, and what innovative steps are being taken to improve their ecological footprint?

The production cycle always starts with a pre-expander. It offers enormous potential for saving resources. We are currently equipping our pre-expanders with additional dosing systems for the addition of recycled EPS raw material.

Since EPS is 100% recyclable and in the course of a functioning circular economy, it is becoming increasingly important to bring the material back into the loop.


Managing complex machinery is a task that comes with its challenges. What are the most testing aspects of your role, and how do you manage them?

The biggest challenge is to bring together the interests of all those involved so that, at the end of the day, we can offer our customers a pre-expander that leaves nothing to be desired. To work out solutions, you have to know who has what strengths in the company. Then it’s a case of “talking brings people together”, that is, finding the right solutions with a lot of persuasion and backing up with facts.


Could you share an account of a significant problem you’ve faced with the pre-expanders and the approach you took to resolve it?

When I started in the industry, the density tolerance was between 3 – 5 % and the particle size distribution was not very good! By closely observing the process and studying many foaming protocols, I managed to find a way to reduce the tolerance to 1 %, which solved the particle size problem by itself! Every customer learns how to do this during training on our HIRSCH pre-expander.


As technology surrounding pre-expanders advances, in what ways does this affect the entire EPS manufacturing sector?

When an EPS converter sees what is possible with our pre-expanders, they immediately compare it with what they currently have. It then quickly becomes clear that switching to our technology goes hand in hand with saving material and energy!


What initially piqued your interest in EPS technology, and what motivates you to continue pursuing innovation within this realm?

When you work in this industry and see a lot of different companies a year, you get a lot of impressions and are constantly faced with problems that need to be solved. Customers’ requirements are constantly changing, so things are always moving forward. Having satisfied customers is what drives me!


From your vantage point, what are the essential considerations for customers looking to invest in new pre-expander technology?

You can very quickly calculate what savings potential there is using the current density tolerance and personnel deployment. The “downtime” of the existing system can also be calculated. Furthermore, in the event of a problem, support is available in the shortest possible time to continue production.

Every customer can calculate this using their annual raw material consumption. Therefore, they can quickly realise that the product quality has increased as a result of the changeover!


For those looking to embark on a career in the EPS industry or in a speciality similar to yours, what advice could you impart?

It was important for me to communicate with everyone in the industry. This starts with the customer, the raw material manufacturer, then goes on to the machine operator, especially in our own EPS production facilities, the designer and programmer, right through to sales and management. If you have information from all areas, it makes it easier to achieve a successful product! It is also important to never let up if you are convinced of something or absolutely want to realise it!

I would like to take this opportunity to thank everyone who has supported me in the past and continues to do so! The fact that our pre-expander is the market leader is thanks to all of us. We are like a clockwork in which one cog meshes with another. I am the pendulum!


Rainer Hormann’s expertise illuminates the significant strides in pre-expander technology that have enhanced the EPS industry’s efficiency and sustainability. His dedication to innovation and customer collaboration has not only advanced HIRSCH’s machinery but has also contributed to the broader goals of resource conservation and environmental responsibility. As we conclude our insightful conversation, it’s clear that Rainer’s impact on the EPS landscape extends far beyond the machinery he helps perfect, embodying the forward-thinking spirit crucial for the industry’s future.

Testing before delivery to customer.


Double dosing for the addition of recycled “raw” EPS during preexpansion

*A pre-expander is a machine which expands the Polystyrene raw material bead with steam to the right size and density needed for various EPS products.