For many people, talking of the infinite vastness of the universe conjures up stories of science fiction, usually told by a Hollywood film studio. However, in real life, more than in any other area, it is arguably in space travel that a strong will and clear vision are vital for creating the necessary technology and readying it for deployment in the cosmos. This was the challenge faced by Swiss technology group RUAG in the construction of its Sentinel satellite, designed for observing our planet from on high. Even here, beyond the Earth's atmosphere, additive manufacturing is playing a key role.
To some extent it squares the circle: we have been able to make a component significantly lighter and yet simultaneously more robust. The component characteristics have proven their worth in tests carried out with the requisite stringency for the aerospace sector. We will be hearing a lot more about additive manufacturing in the coming years – I'm convinced of that!
In such cases, the complete production chain plays an important role, particularly in the aerospace sector. “Obviously, the immense advantages of producing components using additive manufacturing was of great interest to us," explained Franck Mouriaux, General Manager of Structures at RUAG. "For example, design freedom and complex components help us to save weight. The ability to integrate functions is also very helpful. In the end, however, it is a case of identifying these potential advantages, implementing them in an ideal fashion and acquiring the necessary the corresponding authorization. The simplest component serves no purpose if it cannot be used."
Fundamental suitability and rigidity testing formed the starting point of the antenna bracket's design. The next step comprised the selection of material, definition of processes and initial basic tests in respect of the material characteristics. The initial test structures then constructed, to serve as the starting point for the topological optimization of the component. RUAG was eventually able to achieve the – theoretically – perfect form for the antenna bracket, through a combination of intensive work with a CAD and FEM system from Altair and guidance from EOS on design and construction using additive manufacturing.
The approximately 40 cm long antenna bracket was produced by citim GmbH from Barleben in Germany using of the EOS M 400. With a construction volume of 400 x 400 x 400 mm, it was possible to produce two antennas, 30 tensile test pieces and various test items in a single construction order. The construction time was approximately 80 hours. The parameter set used was for a layer thickness of 60 µm, optimized for surface quality and productivity.
The aluminium alloy used, EOS Aluminium AlSi10Mg, is characterized by high strength and strong resistance to dynamic stress, making the material perfectly suited for use with high-stress components. Comprehensive tests were carried out to demonstrate the required characteristics – in the aerospace sector, these comprise up to 80 % of the total scope of a project. Specially manufactured structures were used for testing. Among other things, engineers examined the brackets in computer tomographs. Various mechanical and physical procedures were also performed. At times, the stresses brought to bear on the component deliberately exceeded the load limits, ultimately leading to the destruction of the test pieces.
EOS combines innovation with great experience in additive manufacturing. The systems offer really interesting possibilities for all markets across every sector.