Special Order from Lund, New large-scale instrument at ZEA-1
Manufacturing high-precision components at the limit of what is technically feasible? No problem for the new five-axis machining centre at ZEA-1. Engineer Dr. Yannick Beßler is responsible for the first order – with an important component for the ESS neutron source in Sweden.
It sits like a bungalow in the middle of the ZEA-1 hall – covering about 80 square metres, with large windows. Glancing through the windows, however, you will not see any tables or sofas. Instead, this is where high-precision tools mill metal, forming unusual components, sometimes over several weeks. Welcome to the new five-axis machining centre, which has been in operation at ZEA-1 since mid-May!
Engineer Dr. Yannick Beßler and his colleagues at ZEA-1 simply call the new addition, which weighs around 40 tons, “the big milling machine” – while the €-1.6-million machine is one of the best of its kind. “Five axes mean that we can process the material from all directions and angles,” says Beßler, who is responsible for the first major order with the technology giant. “Even a sixth axis can be used locally, which allows the production of particularly complicated shapes.” Besides, the sheer size of the device is something extraordinary. “We can use it to produce high-precision components ranging from a few millimetres to two metres in size,” says the engineer with some pride.
The heart of the neutron source
According to the 38-year-old, who has been working at ZEA-1 for ten years, the large machine is not only convincing at milling, however. “For example, it can change up to 120 different tools on its own.” The heavy parts no longer have to be complicatedly and tediously replaced by hand. “Since many other things are automated as well, the milling machine can even run alone, to some extent, overnight,” says Beßler. In addition, digital 3-D models of the desired component can be fed directly into the device. This saves time and prevents errors that can creep in during manual programming, according to the engineer. In keeping with the extraordinary capabilities of the device, the first task is already quite a challenge: “We are manufacturing the heart of the neutron source of the ESS,” says Beßler.
ESS stands for European Spallation Source, a €-2-billion, large-scale research facility under construction in Lund, Sweden. From 2023 onwards, it is intended to provide neutrons for scientists from different research fields. “For example, this enables us to observe plants growing on the molecular level,” says Beßler. Since Forschungszentrum Jülich leads the way in neutron research in Germany, it holds the leading role of Germany’s involvement in the project. Beßler and his colleagues are responsible for building the neutron source’s so-called twister.
The clock is ticking!
For the sheathing of the twister, a total of nine individual parts – each of them one and a half metres long – are currently being milled at the five-axis machining centre. Ten tons of specially manufactured stainless steel worth € 200,000 are used for this purpose. In the future, the sheathing will shield the high-energy neutrons from the outside, thus protecting electronics and people, among other things. “In order for this not to go wrong, the individual components must fit extremely accurately,” explains Beßler. In addition, very different three-dimensional geometries, such as fine cooling channels, are being milled. The production of one single component can take weeks. “Industry doesn’t venture to address complex ESS neutron source projects like our twister in the first place,” he says. As soon as all parts are finished, they will be assembled with the other components of the twister at Jülich. Time is pressing, but Beßler is confident that the functional twister will be delivered to Sweden at the turn of the year, as planned – despite the corona pandemic. This would be the first practical test for the five-axis machining centre, and the next challenges are already waiting on Forschungszentrum Jülich’s campus.
Helpful for Jülich research
The new milling machine is a real benefit for Forschungszentrum Jülich as a whole. The colleagues at ZEA-1 can now produce a much wider range of components for the scientific community on site. Many Jülich research areas – such as neutron, energy and climate research – can benefit from this, and other technology units will also be able to use this special machine.
First order: the twister for Lund
The twister for the ESS is a kind of huge brake block for tiny particles – and part of the target station there (pictured), where the neutrons are released. While the twister is 6.5 metres long and weighs 14 tons, the diameter of the neutrons is about one trillion times smaller than that of a grain of sand. Usually the tiny creatures are firmly anchored in atomic nuclei. In order for researchers to be able to use them for their experiments, they must first be released. This is done with the help of similarly tiny particles, the protons, which are accelerated in a tube several hundred metres long and then shot at a layer of heavy metal. This bombardment releases neutrons from the metal atoms, which then fly fast and helter-skelter. The twister from Jülich decelerates the particles to similar speeds and bundles them into a uniform beam that can be used for experiments.