The new additively manufactured valve block offers the same performance as the conventional one, but is 35% lighter and is made from a titanium alloy.
The company, whose additive manufacturing program was launched six years ago, wanted to substitute a conventional primary flight component, in particular a high-pressure hydraulic valve block, with an additively manufactured one. Amid increasing ecological awareness, and rising fuel prices, there’s an growing call for lightweighting in the aviation sector. Liebherr Aerospace wanted to utilise additive manufacturing to deliver a lighter component, while meeting safety and efficiency regulations.
Traditionally, the manufacture of a valve block starts from forged materials, which is machined, trimmed, drilled and then assembled. It’s a time-consuming process, complex too, and leaves little room for optimisation, and even smaller margin for error. But this only strengthened the argument for a simpler process.
Liebherr led a project, which had contributions from Airbus and a research team from the Chemnitz University of Technology and was funded by the Federal Ministry for Economic Affairs and Energy (BMWi), to find a solution. After analysing the conventional part, the hydraulic structures were identified and auxiliary sections removed. Some of the main components were re-positioned according to the new-found space, and due to interface requirements which sought to optimise intelligent and short connection lines.
“With industrial 3D printing, complexity is no longer an issue,” said Alexander Altmann, Lead Engineer Additive Manufacturing, Research & Technology at Liebherr Aerospace. “On the EOS M 290 system, components are built up from a large number of thin layers, each 30 to 60 μm thick, which enables us to build complex geometries. The functional elements were directly connected to one another using curved pipes. This avoided the need for a complex system of pipes with lots of transverse bores, saving time in production.”
The part was printed in titanium alloy, suitable for aviation applications because of its lightness, mechanical properties, and resistance to corrosion. Having been successfully trialled in a test flight on the Airbus A380 aircraft, the 3D printed valve block has proved functional and safe. It also offers the same performance as the conventionally made part, and is 35% lighter and made from fewer parts. Liebherr was also able to integrate ten functional elements into the new valve block, eliminating the complex system of pipework with multiple transverse bores.
“That might as well be the tagline for additive manufacturing – making the same things but with less mass and fewer parts,” Altmann summarised. “Today, it takes about a day to manufacture a valve block and we see the potential to decrease building time by more than 75% with the EOS M 400-4. This is a significant step for us at Liebherr Aerospace.”
Since the demands placed on aircraft components are so high, Liebherr has a firm focus on additive manufacturing processes to ensure parts made with these methods are reliable. EOS, while providing the technology for Liebherr to 3D print the valve block, also lends a hand in the quality assurance of the components made with its 3D printing systems. The partnership between the two companies saw Liebherr participate in a pilot phase of the EOSTATE Exposure OT, a new module of the EOS monitoring suite for real-time component inspection.
“In the future, this will speed up the identification of material defects during the industrial 3D printing process and will help to reduce the need for downstream quality assurance processes, such as computer tomography,” Altmann said.