The aerospace industry has been seeking additive manufacturing to improve efficiency and reduce waste, and has become an early and enthusiastic adopter of additive manufacturing. Additive manufacturing technology has been used to manufacture brackets inside aircraft; it has been used to print engine parts, which has greatly reduced the number of components; it has even been used to produce 21 kg drones to test new technologies.
ExOne, an adhesive-jet additive manufacturing technology company, believes that parts made with 3D printing technology are commonly used in aerospace products. An example is the Sikorsky CH-53 heavy helicopter, which uses a composite air duct made of ExOne 3D printing tools. This benefit is two-way, and the interest of aerospace companies has also encouraged the advancement of 3D printing. The aerospace industry has a strong demand for the functions of additive manufacturing. Large aerospace manufacturers around the world are telling their 3D printing stories. It has been verified, which allows people to take more demanding applications more seriously.
GE Aviation: Improving the innovative capabilities of additive manufacturing
For various reasons, aerospace is attracted by additive manufacturing. First of all, the aviation industry widely uses expensive metals, such as titanium. In traditional subtractive manufacturing, more than 90% of the material is removed, resulting in a severe buy to fly ratio (BFT: buy to fly ratio). 3D printing enables new shapes, which means that the number of parts that need to be manufactured will be reduced. With 3D printing, less material is wasted. Oak Ridge National Laboratory (ORNL) believes that aerospace products must use large amounts of titanium, and will get a lot of waste. In terms of cutting tools, titanium is cruel. Titanium is difficult to machine, increasing downtime and tool costs, but titanium is easy to 3D print.
3D printing is also seen as a way to use lighter materials. In addition to titanium, such materials include aluminum, carbon fiber, and composite materials. For some parts, the weight can be reduced by about half. Lightweighting is important-the heavier the thing, the greater the energy required to keep it in the air. The aerospace industry is willing to pay a premium for additive manufacturing parts. All aerospace companies have done calculations and declared how additive manufacturing can improve their competitiveness.
General Electric has always been one of the leading adopters of additive manufacturing. CFM is a flat-share joint venture between GE Aviation and the French Safran Group. It has four 3D printed parts certified by the US Federal Aviation Administration. They are the T25 sensor and CFM LEAP fuel nozzle head for GE90-94B, as well as the GEnx-2B electric door opening system (PDOS) bracket and GE Passport gas-oil separator.
The fuel nozzle system of the CFM LEAP engine was first put into production at a factory in Alabama in 2015. This is one of the first aerospace systems known for 3D printing. Last year, the plant produced the 30,000th fuel nozzle head, which is also used in GEnx PDOS brackets. GE has also developed GE Catalyst, a turboprop engine that can combine 855 conventional parts into 12 components, while GE9X combines more than 300 conventional parts into only 7 3D printed components. GE Aviation said it has confirmed more than 80 parts to be 3D printed.
GE Aviation's additive manufacturing started with the introduction of a large number of new products, but the focus has shifted to reducing the cost of existing products. Additive manufacturing provides GE engineers with a new degree of creative freedom, fundamentally changing the way they design. The paradigm between manufacturing cost and design complexity has been subverted. Using additive manufacturing, the design can be optimized to improve performance. 3D printing can speed up part production and testing. Due to faster part output, the company completed the bench test of the Catalyst combustion chamber six months in advance.
GE also invested in this technology by acquiring a majority stake in German concept laser company and Swedish Arcam AB. As GE Additive Manufacturing develops, its business can provide feedback and make adjustments within hours instead of months. As the company continues to develop additive manufacturing engineering and manufacturing capabilities, these investments have made GE Aviation a better supplier of additive manufacturing equipment. ORNL believes that GE has made great contributions to the development of 3D printing in the aerospace field.
Airbus: Rapid production of spare parts to meet demand
Airbus Group is another manufacturer of aircraft that uses 3D printing. Since 2015, Airbus has conducted test flights of its small pilot drones that 'test high-tech targets in reality.' About 90% of its structural components are 3D printed from plastic polyamide powder. Airbus described THOR as 'a platform for realizing low-risk and rapid development of different technologies under actual flight conditions.' Airbus used additive manufacturing technology to increase THOR's development speed, which took seven weeks to print The 60 structural parts took another week to assemble the aircraft.
Airbus has expanded its use of additive manufacturing in other ways. Five years ago, the company began to use 3D printing or so-called 'additive layer manufacturing' (ALM) to make stents. Airbus said this is the first step in a long-term strategy to gradually introduce ALM technology. Over the past 5 years, Airbus has gradually increased the number of ALM applications in volume production and in-service aircraft. The company has produced and installed more than 70,000 3D printed parts on Airbus aircraft. Most of the parts are printed with polymers, but more and more titanium and nickel-based alloys are used.
3D printed spare parts made of polymers have been used on A350 XWB series aircraft. Some A320neo and A350 XWB test aircraft are equipped with metal printed cockpit brackets and fuel lines. The company said that more metal parts are in the process of certification. Special additive manufacturing technologies used by Airbus include filament deposition and powder bed polymer technology, metal powder bed and metal wire directional energy deposition. Currently, Airbus is satisfied with the amount of materials available for 3D printing. The qualification of using ALM in the aviation industry is very demanding in terms of cost and time. Therefore, the focus of Airbus is to introduce this technology on several common metal alloys that have identified value creation opportunities.
Airbus is collaborating with Autodesk's generative design to use artificial intelligence to redesign parts that are now designed for other manufacturing technologies and now need to be 3D printed. In 2015, Airbus introduced the so-called 'bionic partition', which is a metal 3D printed wall and rear seat support structure that separates the cabin from the aircraft kitchen. The separator is about 45% lighter than conventionally manufactured separators, and Airbus intends to produce the separator for the A320 aircraft. However, Airbus expects the cost of metal 3D printing to fall faster. Autodesk is slightly modifying the design so that it has many of the same advantages. This second design requires a 3D printed plastic mold of the separator, which will be cast from an alloy that has been certified for flight. The mold still allows for more complex shapes, and the second version of the separator is in the process of certification.
New metals in the aerospace market
Additive manufacturing companies are working hard to meet the needs of the aerospace market. For example, EOS is an industrial 3D printer manufacturer that uses direct metal laser sintering and has begun to introduce more metals for printing. In the past 5 years, the company has developed 10 more metals, which is not a lot. People want to ensure that high-quality parts can be manufactured, and there are always challenges, and it takes time to develop them.
For EOS, the key aerospace market is rocket engines. One of the customers is Launcher, established in 2017, dedicated to the development of rockets for launching satellites. Last year, Launcher successfully tested the ignition performance of 3D printed copper alloy engines printed on EOS machine tools. EOS has studied the progress of engine development with Launcher and expects to manufacture engines with very large payloads in the future. More and more private companies are involved in rockets, and 3D printing has accelerated this development-people can complete the design today or within a week or two, in fact, they can also put parts on the desk, and can do some of it test. The rocket industry now looks very exciting.
Another EOS customer was able to reduce weight through 3D printing. They put a small bread-sized aluminum box inside the satellite through additive manufacturing to reduce its weight by about 20%. ExOne is also active in the aerospace industry. Since 2002, ExOne's Sand 3D printers have entered the industrial market including aerospace, and they manufacture cores for metal casting. Now the time to design a mold and obtain a good part can be greatly reduced from weeks and months to days or hours. In addition to increasing complexity without increasing cost and mold storage, 3D printing also allows rapid design iterations. The foundry is moving towards 3D printing, and 3D printing sand casting has been actively adopted.
ExOne invented an erosion tooling for sacrificial tooling for laminated composite materials (including carbon fiber and glass fiber composite materials). ExOne has developed a process for flushing 3D printing tooling with water. The material remains water-soluble up to 180 degrees Celsius. The process is being used to manufacture composite materials for Sikorsky, a subsidiary of Lockheed Martin, and Royal Engineering Composites. ExOne also provides a complete series of metal 3D printers that can directly print metals such as Inconel 718, and it can also print ceramics such as silicon carbide. 3D printing has been able to penetrate the aerospace field, people tend to have more complex castings, ExOne and Sikorsky have done a lot of work.
It is expected that 3D printing will make more progress in the next five years. It will be tested, tested and retested. The additive supply chain will actually grow in the next five years. Airbus said it will follow its plan and gradually expand its application areas and related value creation opportunities. Compared with traditional technologies, competitiveness and market share will gradually increase with the rise of new applications. ORNL believes that 3D printing will become larger and larger in the aerospace field, and large structural components are areas that some companies have begun to study. People's confidence in the aerospace industry is increasing day by day, and additive manufacturing will bring greater changes in the future.