By Melissa Donovan
Participants in the aerospace industry turn to additive manufacturing (AM) to minimize complex parts production and create a lighter weight alternative. Overall, companies in this industry constantly looking for ways to decrease weight in airplanes and other flying machines to optimize travel conditions and reduce fuel consumption.
Pushing the Limits
Liebherr-Aerospace celebrates over five decades supplying systems for the aviation industry. Equipment developed, produced, and serviced includes flight control and actuation systems, landing gear, air management systems, gears, and gearboxes.
Roughly six years ago, Liebherr launched its AM program with the goal of working with new technologies to remain competitive in an industry with rising fuel prices and a lack of alternative energy sources. Looking at powder bed based industrial three-dimensional (3D) printing in particular, it chose EOS metal 3D printing technology.
To push the limits of what 3D technology can accomplish, it looked to substitute a conventional primary flight control hydraulic component with an AM part that fulfilled all certification requirements for flight. Partly funded by the German Federal Ministry of Economic Affairs and Energy, Liebherr collaborated on this project with Airbus and the Chemnitz University of Technology in Germany.
Conventionally, flight control hydraulic components—in this scenario a valve block—are forged from raw material that is then machined, trimmed, drilled, and assembled. Time consuming and complex, the process leaves little room for error but the number of steps illustrates possible improvements made with 3D printing technologies.
The solution, turning to an EOS device to manufacture a lightweight 3D printed component, specifically a high-pressure hydraulic valve block, with fewer parts and in an efficient process chain.
First, the original hydraulic valve block was analyzed. Hydraulic structures were identified and auxiliary sections removed. The positioning of the main components was reconsidered for full optimization in the design of the new part.
An EOS M 290 system was used to build the hydraulic component. With a build volume of 250x250x325 millimeters (mm), the EOS M 290 allows for fast, flexible, and cost-effective production of metal parts directly from CAD data. An intuitive user interface, intelligent software concept with a combination of open and standardized parameter sets, and improved filter system are specially designed for industrial production. The robust system design and the powerful 400-watt fiber laser enable a reliably high performance.
“With industrial 3D printing, complexity is suddenly no longer an issue. On the EOS system, components are built up from a large number of thin layers, each 30 to 60 µm thick, which enabled us to build complex geometries. The functional elements were directly connected to one another using curved pipes. This avoids the need for a complex system of pipes with lots of transverse bores, saving time in production,” explains Alexander Altmann, lead engineer AM research and technology, Liebherr.
Titanium alloy was chosen for the build material because it is light, mechanically stable, and offers good corrosion resistance. All reasons for it being suitable in the construction of aviation parts.
The metal 3D printed primary flight control hydraulic component was 35 percent less weight and ten parts were eliminated compared to the conventionally manufactured part. “That might as well be the tagline for AM—making the same things but with less mass and fewer parts—however this is a significant step for us at Liebherr,” adds Altmann.
In addition, it fulfilled all certification requirements for flight. The 3D printed valve block was successfully tested on a flight with an Airbus A380 aircraft.
Fully Invested
After this specific project, proving that AM with EOS technology is feasible for building critical primary flight components, Liebherr is fully invested in 3D printing. For example, it now takes a day to manufacture a hydraulic valve block, but the company sees potential in decreasing building time by more than 75 percent if using the EOS M 400-4.
Designed for industrial applications, the EOS M 400-4 offers a large building volume of 400x400x400 mm combined with four lasers for up to four times higher productivity. It shatters boundaries of manufacturing as it meets the most demanding requirements of modern production environments in terms of efficiency, scalability, usability, and process monitoring. The modular platform design easily integrates into existing production environments and flexibly consolidated with future innovation. While the sister system EOS M 400 runs with a single 1000W laser, the EOS M 400-4 multiplies the capacity of the EOS M 290, both ensuring proven direct metal laser sintering quality. All EOS M 290 processes can be transferred to the EOS M 400-4 while retaining equivalent part properties.
Liebherr continues to partner with EOS. It participated in the pilot phase of EOSTATE Exposure OT, which is a new module of the EOS monitoring suite that enables seamless and real-time component inspection.
Simplification
With EOS 3D printing technology Leibherr was able to take a common hydraulic part and simplify it drastically. The result was a lighter weight and a diminished build time, both important cost and time savings for the company.
Apr2020, Industrial Print Magazine