Italian OEM and Tier 1 supplier Leonardo collaborated with the CETMA R&D department to develop new composite materials, machines and processes, including induction welding for on-site consolidation of thermoplastic composites. #Trend#cleansky#f-35
Leonardo Aerostructures, a leader in the production of composite materials, produces one-piece fuselage barrels for the Boeing 787. It is working with CETMA to develop new technologies including continuous compression molding (CCM) and SQRTM (bottom). Production technology. Source | Leonardo and CETMA
This blog is based on my interview with Stefano Corvaglia, material engineer, R&D director and intellectual property manager of Leonardo’s aircraft structure department (Grottaglie, Pomigliano, Foggia, Nola production facilities, southern Italy), and an interview with Dr. Silvio Pappadà, research engineer and head. Project of cooperation between CETMA (Brindisi, Italy) and Leonardo.
Leonardo (Rome, Italy) is one of the world’s major players in the aerospace, defense and security fields, with a turnover of 13.8 billion euros and more than 40,000 employees worldwide. The company provides comprehensive solutions for air, land, sea, space, network and security, and unmanned systems worldwide. Leonardo’s R&D investment is approximately 1.5 billion euros (11% of 2019 revenue), ranking second in Europe and fourth in the world in terms of research investment in the aerospace and defense fields.
Leonardo Aerostructures produces one-piece composite fuselage barrels for parts 44 and 46 of the Boeing 787 Dreamliner. Source | Leonardo
Leonardo, through its aviation structure department, provides the world’s major civil aircraft programs with the manufacture and assembly of large structural components of composite and traditional materials, including the fuselage and tail.
Leonardo Aerostructures produces composite horizontal stabilizers for the Boeing 787 Dreamliner. Source | Leonardo
In terms of composite materials, Leonardo’s Aerospace Structure Division produces “one-piece barrels” for the Boeing 787 central fuselage sections 44 and 46 at its Grottaglie plant and the horizontal stabilizers at its Foggia plant, accounting for approximately 14% of the 787 fuselage. %. The production of other composite structure products includes manufacturing and assembling the rear wing of the ATR and Airbus A220 commercial aircraft at its Foggia Plant. Foggia also produces composite parts for the Boeing 767 and military programs, including the Joint Strike Fighter F-35, the Eurofighter Typhoon fighter, the C-27J military transport aircraft, and the Falco Xplorer, the latest member of the Falco unmanned aircraft family produced by Leonardo.
”Together with CETMA, we are doing many activities, such as in thermoplastic composites and resin transfer molding (RTM),” Corvaglia said. “Our goal is to prepare R&D activities for production in the shortest possible time. In our department (R&D and IP management), we also seek disruptive technologies with lower TRL (technical readiness level-ie, The lower TRL is nascent and farther from production), but we hope to be more competitive and provide help to customers around the world.”
Pappadà added: “Since our joint efforts, we have been working hard to reduce costs and environmental impact. We have found that thermoplastic composites (TPC) have been reduced compared to thermoset materials.”
Corvaglia pointed out: “We developed these technologies together with Silvio’s team and built some automated battery prototypes to evaluate them in production.”
”CCM is a great example of our joint efforts,” Pappadà said. “Leonardo has identified certain components made of thermoset composite materials. Together we explored the technology of providing these components in TPC, focusing on the places where there are a large number of parts on the aircraft, such as splicing structures and simple geometric shapes. Uprights.”
Parts manufactured using CETMA’s continuous compression molding production line. Source | “CETMA: Italian Composite Materials R&D Innovation”
He continued: “We need a new production technology with low cost and high productivity.” He pointed out that in the past, a large amount of waste was generated during the manufacture of a single TPC component. “So, we produced a mesh shape based on non-isothermal compression molding technology, but we made some innovations (patent pending) to reduce waste. We designed a fully automatic unit for this, and then an Italian company built it for us. “
According to Pappadà, the unit can produce components designed by Leonardo, “one component every 5 minutes, working 24 hours a day.” However, his team then had to figure out how to produce the preforms. He explained: “In the beginning, we needed a flat lamination process, because this was the bottleneck at the time.” “So, our process started with a blank (flat laminate), and then heated it in an infrared (IR) oven. , And then put into the press for forming. Flat laminates are usually produced using large presses, which require 4-5 hours of cycle time. We decided to study a new method that can produce flat laminates faster. Therefore, in Leonardo With the support of engineers, we developed a high-productivity CCM production line in CETMA. We reduced the cycle time of 1m by 1m parts to 15 minutes. What’s important is that this is a continuous process, so we can produce unlimited length.”
The infrared thermal imager (IRT) camera in the SPARE progressive roll forming line helps CETMA understand the temperature distribution during the production process and generate 3D analysis to verify the computer model during the CCM development process. Source | “CETMA: Italian Composite Materials R&D Innovation”
However, how does this new product compare with the CCM that Xperion (now XELIS, Markdorf, Germany) has used for more than ten years? Pappadà said: “We have developed analytical and numerical models that can predict defects such as voids.” “We have collaborated with Leonardo and the University of Salento (Lecce, Italy) to understand the parameters and their Impact on quality. We use these models to develop this new CCM, where we can have a high thickness but can also achieve high quality. With these models, we can not only optimize temperature and pressure, but also optimize their Application method. You can develop many techniques to evenly distribute temperature and pressure. However, we need to understand the impact of these factors on the mechanical properties and defect growth of composite structures.”
Pappadà continued: “Our technology is more flexible. Similarly, CCM was developed 20 years ago, but there is no information about it because the few companies that use it do not share knowledge and expertise. Therefore, we must start from scratch, only Based on our understanding of composite materials and processing.”
”We are now going through internal plans and working with customers to find the components of these new technologies,” Corvaglia said. “These parts may need to be redesigned and requalified before production can begin.” Why? “The goal is to make the aircraft as light as possible, but at a competitive price. Therefore, we must also optimize the thickness. However, we may find that one part can reduce weight, or identify multiple parts with similar shapes, which can save a lot of money cost.”
He reiterated that until now, this technology has been in the hands of a few people. “But we have developed alternative technologies to automate these processes by adding more advanced press moldings. We put in a flat laminate and then take out a part of it, ready to use. We are in the process of redesigning parts and developing flat or profiled parts. The stage of CCM.”
”We now have a very flexible CCM production line in CETMA,” Pappadà said. “Here we can apply different pressures as needed to achieve complex shapes. The product line we will develop together with Leonardo will be more focused on meeting its specific Required components. We believe that different CCM lines can be used for flat and L-shaped stringers instead of more complex shapes. In this way, compared with the large presses currently used to produce complex geometrical TPC parts, we can make the equipment cost Keep it low.”
CETMA uses CCM to produce stringers and panels from carbon fiber/PEKK one-way tape, and then uses induction welding of this keel bundle demonstrator to connect them in the Clean Sky 2 KEELBEMAN project managed by EURECAT. Source|”A demonstrator for welding thermoplastic keel beams is realized.”
”Induction welding is very interesting for composite materials, because the temperature can be adjusted and controlled very well, the heating is very fast and the control is very precise,” Pappadà said. “Together with Leonardo, we developed induction welding to join TPC components. But now we are considering using induction welding for in-situ consolidation (ISC) of TPC tape. To this end, we have developed a new carbon fiber tape, It can be heated very quickly by induction welding using a special machine. The tape uses the same base material as the commercial tape, but has a different architecture to improve electromagnetic heating. While optimizing the mechanical properties, we are also considering the process to try to meet Different requirements, such as how to deal with them cost-effectively and efficiently through automation.”
He pointed out that it is difficult to achieve ISC with TPC tape with good productivity. “In order to use it for industrial production, you must heat and cool faster and apply pressure in a very controlled way. Therefore, we decided to use induction welding to heat only a small area where the material is consolidated, and the rest Laminates are kept cold.” Pappadà says that the TRL for induction welding used for assembly is higher. “
On-site integration using induction heating seems extremely disruptive-currently, no other OEM or tier supplier is doing this publicly. “Yes, this may be disruptive technology,” Corvaglia said. “We have applied for patents for the machine and materials. Our goal is a product comparable to thermoset composite materials. Many people try to use TPC for AFP (Automatic Fiber Placement), but the second step must be combined. In terms of geometry, This is a big limitation in terms of cost, cycle time and part size. In fact, we may change the way we produce aerospace parts.”
In addition to thermoplastics, Leonardo continues to research RTM technology. “This is another area where we are cooperating with CETMA, and new developments based on the old technology (SQRTM in this case) have been patented. Qualified resin transfer molding originally developed by Radius Engineering (Salt Lake City, Utah, USA) (SQRTM). Corvaglia said: “It is important to have an autoclave (OOA) method that allows us to use materials that are already qualified. “This also allows us to use prepregs with well-known characteristics and qualities. We have used this technology to design, demonstrate and apply for a patent for aircraft window frames. “
In spite of COVID-19, CETMA is still processing the Leonardo program, here is shown the use of SQRTM to make aircraft window structures to achieve defect-free components and speed up pre-forming compared to traditional RTM technology. Therefore, Leonardo can replace complex metal parts with mesh composite parts without further processing. Source | CETMA, Leonardo.
Pappadà pointed out: “This is also an older technology, but if you go online, you can’t find information about this technology.” Once again, we are using analytical models to predict and optimize process parameters. With this technology, we can obtain a good resin distribution-no dry areas or resin accumulation-and almost zero porosity. Because we can control the fiber content, we can produce very high structural properties, and the technology can be used to produce complex shapes. We use the same materials that meet the autoclave curing requirements, but use the OOA method, but you can also decide to use a fast curing resin to shorten the cycle time to a few minutes. “
”Even with the current prepreg, we have reduced the curing time,” Corvaglia said. “For example, compared to a normal autoclave cycle of 8-10 hours, for parts such as window frames, SQRTM can be used for 3-4 hours. Heat and pressure are directly applied to the parts, and the heating mass is less. In addition, the heating of liquid resin in the autoclave is faster than the air, and the quality of the parts is also excellent, which is especially beneficial for complex shapes. No rework, almost zero voids and excellent surface quality, because the tool is in Control it, not the vacuum bag.
Leonardo is using a variety of technologies to innovate. Due to the rapid development of technology, it believes that investment in high-risk R&D (low TRL) is essential for the development of new technologies needed for future products, which exceeds the incremental (short-term) development capabilities that existing products already possess. Leonardo’s 2030 R&D master plan combines such a combination of short-term and long-term strategies, which is a unified vision for a sustainable and competitive company.
As part of this plan, it will launch Leonardo Labs, an international corporate R&D laboratory network dedicated to R&D and innovation. By 2020, the company will seek to open the first six Leonardo laboratories in Milan, Turin, Genoa, Rome, Naples and Taranto, and is recruiting 68 researchers (Leonardo Research Fellows) with skills in the following fields ): 36 autonomous intelligent systems for artificial intelligence positions, 15 big data analysis, 6 high-performance computing, 4 aviation platform electrification, 5 materials and structures, and 2 quantum technologies. Leonardo Laboratory will play the role of an innovation post and the creator of Leonardo’s future technology.
It is worth noting that Leonardo’s technology commercialized on aircraft may also be applied in its land and sea departments. Stay tuned for more updates on Leonardo and its potential impact on composite materials.
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Post time: Feb-09-2021