Bühler’s new flagship hammer mill

Ten years of innovation packed into one machine

How do you successfully bring innovation to a proven machine category? The hammer mill has been around for a century and is used today in scores of different industries worldwide, yet a team at Bühler thought there was potential for improvement and set themselves this challenge. The Granulex® 5 Series Hammer Mill portfolio is the result – a machine that brings together a decade of development to make a huge leap in performance.


 ONE OF THE MOST  widely used and adaptable pieces of grinding equipment, hammer mills are found in most industrial food, feed, and grain processing facilities. There are many applications, and for each one there is a specific hammer mill design. Indeed, the variety of designs on offer is so great it can sometimes be difficult for customers to decide which is the best for their application. A team at Bühler set out to tackle this challenge by creating one hammer mill to meet all the different requirements. “We decided to make the best, most flexible hammer mill system available,” explains Dean Ekkaia, Product Management Director at Bühler.

To do this they looked not just at applications for animal feed production, but also across Bühler’s  Grains & Food business. The team drew on over  10 years of research and development (R&D) in  hammer mill technology. “Over the past decade we  have made many individual developments. We built  test grinding labs and tried out hundreds of new  designs and concepts all around the world. All of  this R&D is packed into our new flagship hammer mill,” says Ekkaia.

The result is the Granulex® 5, a modular system  that can be configured in 360 different customized  and  optimized arrangements using only four machine footprints. This enables the customer to  choose and install the most efficient equipment to  meet their specific requirements in their industry.  The new hammer mill also has the highest through- put ranges, an improved granulation profile, and  reduced energy use per ton of ground product, all  brought together in an operator-friendly design and  that can be connected to Bühler Insights to enable  data-based decision making.


We decided to make the best, most flexible hammer mill system available for our customers.

DEAN EKKAIA, Product Management Director at Bühler

> 10%

capacity increase

> 10%

reduction in energy per ton


reduction in changeover time

Video gallery 🎥

Driven by changing market requirements

Doing more with less is what everyone in business seeks to do, but in today’s difficult energy markets this has become a much more pressing requirement. As grinding is one of the most energy-consuming process steps in many plants, hammer mill customers are keen to find solutions that allow them to get more out with less energy. The Granulex® 5 represents a big jump in performance compared to the competition. “That’s a huge benefit for our customers. They get a better quality of grind and higher throughput with less energy and lower costs – all key factors, in today’s highly com-petitive markets,” Ekkaia explains. Flexibility is also becoming more important for customers due to new requirements on the market. 

Take just one example: the animal feed market. In Europe, animal welfare is an increasingly important factor for consumers. In many supermarkets, meat products are labelled with an animal welfare score. One of the contributors to the score is whether the animal is given feed that is adjusted to its needs. This is where the new hammer mill comes in. “Getting the right level of granularity plays a key role in ensuring the feed is appropriate,” says Reto Bischof, Research & Development Manager at Bühler. “The new Granulex® 5 allows customers to get exactly the level they require.”



Another industry where grinding plays a key role is pet foodmanufacturing. The requirements here are increasing too. With people increasingly seeing their pets as part of the family, they become choosier about the pet food they buy. Pet food manufacturers therefore need a machine that can provide the qual-ity of product that the market demands.“There was a need for a machine that could handle all these shifts in requirements – that could deliver the perfect process for the perfect product,” Bischof explains. “With our new machine we can address these demands.”

Besides the changing nature of the products manufactured using hammer mills, there has also been a change in size requirements, with customers looking for larger machines. The reason behind this is, again, the search for increased efficiency. “Customers want to run one big line rather than two smaller lines. This enables them to increase capacity without having to increase the size of their building to house a second line,” says Bischof.The modular design of the Granulex® 5 meets this need. Similar to the way that automobiles are designed today, Bühler’s new hammer mill offers a basic platform that allows a choice of machine size. The smallest machine size has a single grinding chamber and feeding unit; the largest size has four grinding chambers. With each addition comes a bigger feeding unit and bigger motor, all standing on a sturdy machine base.

Optimized processes

“The grinding chamber is where the magic happens,” says Bischof. Courser or finer grinding can be delivered depending on what is required. The options are covered by two different rotor diameters, either of which can be installed in the same housing and on the same platform. 

The machine can also be configured to achieve many different process parameters, for example by using different screens or with additional impact plates that increase the grinding work applied to the product. The hammer mill can also be run at different speeds and the distance between the hammer and screen can be adjusted.


Our new hammer mill is fully flexible and can adapt to each and every product and end target.


“Today, a customer needs to buy different machines for different applications. We can configure this machine to every application and fine-tune it for every process. This not only produces the best results out of every raw material – it also brings energy efficiencies.”

A decade of innovation

The team also thought hard about how to reduce time and therefore cost in operation. For example, customers often have to change screens, so these have been made more accessible and easier to handle so that they can be changed over very quickly. Some operators change screens once or twice a day, so speed is a huge customer requirement. 

Another time-saving development relates to the hammers themselves. Instead of exchanging hammers one at a time, the novel hammer cage allows groups of hammers to be replaced at the same time. The task can be carried out by a single operator, even for the biggest version of the Granulex® 5. “We have the industry’s fastest screen and hammer changeover for this type of hammer mill,” Ekkaia explains. “That reduces operating expense and downtime.”

The design is both robust and equipped with standard vibration and temperature sensors. The Granulex® 5 is also ready to connect to Bühler cloud applications, enabling further optimization and supporting customers in better decision-making with data transparency and preventive information. It’s an impressive result that has already met with approval from early customers including those who tested the prototype and visitors who witnessed it firsthand at VIV Victam in the Netherlands in early June this year. There isn’t just one key to this success, according to Bischof, but many.

Live development with customers

Customers were involved in the development process from early on. An early version of the machine was installed onsite with Agravis, one of the largest manufacturers of compound feed in Germany. At their plant in Münster, Agravis produce nearly 500,000 tons of feed a year, primarily for pigs, cattle and poultry, and in every structure – flour, pressed and granulated. Rising energy costs mean that the business has been looking for energy-optimized processes. 

With the prototype machine running for hundreds of hours at the Agravis plant, the Bühler team gained insights into the performance and operation and could see and deal with issues directly. Agravis were impressed by the results. “We have an improved feed structure, and we can influence granulation more precisely,” explains Heiko Almann, Managing Director at Agravis. “That’s good for animal welfare and performance. And in comparison to our existing hammer mills, we see energy saving." 


granulex sid view mock up granulex sid view mock up The innovative machine design ensures consistent grinding quality even in demanding industries with high requirements and scaled output.
Watch the video about our customer Agravis who is using Granulex® 5

Gaining early traction in the market

Meanwhile, the machines in the Bühler labs ran next to the development process. This made it possible to see each loop of development directly – as each new feature was implemented, the team could see immediately what worked and fix what didn’t.

This hands-on, design-thinking process means that every element of the Granulex® 5 already has data behind it and is already industry-proven ready for the launch. “We know if it makes the cut and delivers benefits for the customer. And we can prove the performance because we have tested it all along,” says Ekkaia. “We know how the machine performs and how it is optimized. We know about the dependencies in the design, and we also increased our understanding of the principles and specifics of the physics of grinding. It has stepped up our expertise and that is a benefit for our customers.”

There is already high awareness of the new hammer mill, and a lot of demand and interest picked up even prior to the official launch. “We got a good market response from VIV/Victam International in the Netherlands – the most important animal nutri-tion fair in Europe – and at Victam Asia exhibition in Bangkok, the feeling among customers was that our hammer mill is set to become the new benchmark for grinding in the animal feed market,” Bischof explains.

With the new Granulex® 5, customers get finetuned granulation at a lower energy and operational cost. “By pulling together 10 years of R&D, putting all the elements to the test, and bringing all the best pieces together in a modular platform, we’ve succeeded in bringing new innovation to an old machine category,” says Ekkaia. The new hammer mill portfolio will be launched on the market at the end of 2022.


The design process for the Granulex® 5 Series hammer mill was unique for Bühler in that the team started building the machine in the lab even as the development process was ongoing – so each loop of development was directly implemented in the lab, and they could see everything that worked and everything that didn't.

The reason for this is that while computer simulation plays a key role in design, it is not possible to replicate everything in the digital world – particularly not the physical act of grinding a natural product. For this, only hands-on experimentation could deliver the insights that were needed. 

The team therefore built a functional prototype at the application center at Bühler headquarters in Uzwil, Switzerland. It was like a live twin of the digital concept. Whenever they came up with a new feature or module, it was installed in the lab.

This hands-on innovation method was proven when the first machine, installed with an early customer, was switched on. They pushed the green button, and it worked the way they expected, meeting all the requirements from day one.

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