At present, many aerospace companies have realized the unique advantages of the additive manufacturing technology and turned to additive manufacturing (AM) in order to minimize the production of complex parts and create lighter substitute products. In general, companies in the industry have been looking for ways to reduce the weight of aircraft and other aircraft in order to optimize travel conditions and reduce fuel consumption.
Liebherr, the world’s leading supplier of aviation industry, has been in the industry supply system for more than 50 years. Equipment developed, produced and maintained includes flight control and braking systems, landing gears, air management systems, gears and gearboxes.
About six years ago, Liebherr launched a plan to increase manufacturing materials. Its goal is to introduce new technologies to improve customers’ quality and economic products and maintain competitiveness in the industry. Especially in industrial 3D printing based on powder bed, Liebherr finally chose EOS metal 3D printing technology.
In order to break through the limit that 3D technology can achieve, Liebherr View replaces the traditional main flight control hydraulic parts with AM parts that meet all flight certification requirements. With partial financial support from the German Federal Ministry of Economy and Energy, Liebherr carried out the project in cooperation with Airbus and Germany’s Kamnitz University of Technology.
The traditional manufacturing process for flight control hydraulic components (i.e. hydraulic control valves) is forging, followed by machining, trimming, drilling and assembly. The process is time consuming and complicated, and there is little room for optimization. After verification, this complex process can be optimized and improved by 3D printing technology.
The solution turns to EOS equipment to produce lightweight 3D printing components, especially high-pressure hydraulic valve blocks, with fewer parts and an efficient process chain. Firstly, the hydraulic structure is determined and the auxiliary part is removed by analyzing the original hydraulic valve block. The positions of the main components were reconsidered in order to make overall optimization in the design of new parts.
EOS M 290 system is selected for manufacturing hydraulic components. The EOS M 290 has a construction volume of 250x250x325 and can directly use CAD data to produce metal parts quickly, flexibly and cost-effectively. Intuitive user interface, intelligent software concept combining open and standardized parameter sets and improved filter system are designed for industrial production. Powerful system design and 400 watt fiber laser can realize reliable and high performance of the product.
“For industrial 3D printing, complexity is no longer a problem. On EOS system, components are made up of a large number of thin layers, each of which has a thickness of 30 to 60 μm, which enables us to construct complex geometric shapes. The functional elements are directly connected to each other through bent pipes. This avoids the need for complex piping systems with a large number of transverse holes, thus saving production time. ” Alexander Altmann, Liebherr AM’s chief engineer of research and technology, explained.
Titanium alloy was chosen as printing material because of its light weight, stable mechanical properties and good corrosion resistance. Suitable for all conditions of aviation parts manufacturing. Compared with the parts manufactured conventionally, the weight of the main flight control hydraulic parts printed in metal 3D is reduced by 35%, and 10 parts are saved. Alexander Altmann added: “This may also be AM’s slogan-using fewer and lighter parts to make products of the same or better quality happens to be an important step for us Liebherr.”
In addition, the main flight control hydraulic pressure of metal 3D printing also meets all certification requirements for flight. The 3D printed valve block has successfully passed the flight test of Airbus A380.
Valve body manufactured by traditional method (left) and optimized metal 3D printing valve body (right). (Source: Liebherr)
Production scale investment
After the completion of this specific project, it was proved that EOS technology was feasible for manufacturing key major flight components, and Liebherr invested fully in 3D printing. For example, it now takes one day to manufacture hydraulic valve blocks, but they found that if EOS M 400-4 is used, the manufacturing time can be reduced by more than 75%.
EOS M 400-4 is specially designed for industrial applications. It can provide a build volume of 400x400x400 and combines four lasers to increase productivity by four times. It meets the most demanding requirements of modern production environment in terms of efficiency, scalability, usability and process monitoring, breaking the manufacturing boundaries. Modular platform design can be easily integrated into the existing production environment and flexibly integrated with future innovations. Sister system EOS M 400 only uses a single 1000W laser to operate, while EOS M 400-4 is four times the production capacity of EOS M 290, both of which ensure reliable direct metal laser sintering quality. All EOS M 290 processes can be transferred to EOS M 400-4 while maintaining the same part performance.