According to SmarTech, a manufacturing technology consulting company, aerospace is the second largest industry served by additive manufacturing (AM), second only to medicine. However, there is still a lack of awareness of the potential of additive manufacturing of ceramic materials in the rapid manufacture of aerospace components, increased flexibility and cost-effectiveness. AM can produce stronger and lighter ceramic parts faster and more sustainably-reducing labor costs, minimizing manual assembly, and improving efficiency and performance through design developed by modeling, thereby reducing the weight of the aircraft. In addition, additive manufacturing ceramic technology provides dimensional control of finished parts for features smaller than 100 microns.
However, the word ceramic may conjure up the misconception of brittleness. In fact, additive-manufactured ceramics produce lighter, finer parts with great structural strength, toughness, and resistance to a wide temperature range. Forward-looking companies are turning to ceramic manufacturing components, including nozzles and propellers, electrical insulators and turbine blades.
For example, high-purity alumina has high hardness, and has a strong corrosion resistance and temperature range. Components made of alumina are also electrically insulating at the high temperatures common in aerospace systems.
Zirconia-based ceramics can meet many applications with extreme material requirements and high mechanical stress, such as high-end metal molding, valves and bearings. Silicon nitride ceramics have high strength, high toughness and excellent thermal shock resistance, as well as good chemical resistance to the corrosion of a variety of acids, alkalis and molten metals. Silicon nitride is used for insulators, impellers, and high-temperature low-dielectric antennas.
Composite ceramics provide several desirable qualities. Silicon-based ceramics added with alumina and zircon have proven to perform well in the manufacture of single crystal castings for turbine blades. This is because the ceramic core made of this material has very low thermal expansion up to 1,500°C, high porosity, excellent surface quality and good leachability. Printing these cores can produce turbine designs that can withstand higher operating temperatures and increase engine efficiency.
It is well known that injection molding or machining of ceramics is very difficult, and machining provides limited access to the components being manufactured. Features such as thin walls are also difficult to machine.
However, Lithoz uses lithography-based ceramic manufacturing (LCM) to manufacture precise, complex-shaped 3D ceramic components.
Starting from the CAD model, the detailed specifications are digitally transferred to the 3D printer. Then apply the precisely formulated ceramic powder to the top of the transparent vat. The movable construction platform is immersed in the mud and then selectively exposed to visible light from below. The layer image is generated by a digital micro-mirror device (DMD) coupled with the projection system. By repeating this process, a three-dimensional green part can be generated layer by layer. After thermal post-treatment, the binder is removed and the green parts are sintered-combined by a special heating process-to produce a completely dense ceramic part with excellent mechanical properties and surface quality.
LCM technology provides an innovative, cost-effective and faster process for investment casting of turbine engine components-bypassing the expensive and laborious mold manufacturing required for injection molding and lost wax casting.
LCM can also achieve designs that cannot be achieved by other methods, while using far fewer raw materials than other methods.
Despite the great potential of ceramic materials and LCM technology, there is still a gap between AM original equipment manufacturers (OEM) and aerospace designers.
One reason may be resistance to new manufacturing methods in industries with particularly strict safety and quality requirements. Aerospace manufacturing requires many verification and qualification processes, as well as thorough and rigorous testing.
Another obstacle includes the belief that 3D printing is mainly only suitable for one-time rapid prototyping, rather than anything that can be put into use in the air. Again, this is a misunderstanding, and 3D printed ceramic components have been proven to be used in mass production.
An example is the manufacture of turbine blades, where the AM ceramic process produces single crystal (SX) cores, as well as directional solidification (DS) and equiaxed casting (EX) superalloy turbine blades. Cores with complex branch structures, multiple walls and trailing edges less than 200μm can be produced quickly and economically, and the final components have consistent dimensional accuracy and excellent surface finish.
Enhancing communication can bring together aerospace designers and AM OEMs and fully trust ceramic components manufactured using LCM and other technologies. Technology and expertise exist. It needs to change the way of thinking from AM for R&D and prototyping, and see it as the way forward for large-scale commercial applications.
In addition to education, aerospace companies can also invest time in personnel, engineering, and testing. Manufacturers must be familiar with different standards and methods for evaluating ceramics, not metals. For example, Lithoz’s two key ASTM standards for structural ceramics are ASTM C1161 for strength testing and ASTM C1421 for toughness testing. These standards apply to ceramics produced by all methods. In ceramic additive manufacturing, the printing step is just a forming method, and the parts undergo the same type of sintering as traditional ceramics. Therefore, the microstructure of ceramic parts will be very similar to conventional machining.
Based on the continuous advancement of materials and technology, we can confidently say that designers will get more data. New ceramic materials will be developed and customized according to specific engineering needs. Parts made of AM ceramics will complete the certification process for use in aerospace. And will provide better design tools, such as improved modeling software.
By cooperating with LCM technical experts, aerospace companies can introduce AM ceramic processes internally-shortening time, reducing costs, and creating opportunities for the development of the company’s own intellectual property. With foresight and long-term planning, aerospace companies that invest in ceramic technology can reap significant benefits in their entire production portfolio in the next ten years and beyond.
By establishing a partnership with AM Ceramics, aerospace original equipment manufacturers will produce components that were previously unimaginable.
About the author: Shawn Allan is the vice president of additive manufacturing expert Lithoz. You can contact him at sallan@lithoz-america.com.
Shawn Allan will speak on the difficulties of effectively communicating the advantages of ceramic additive manufacturing at the Ceramics Expo in Cleveland, Ohio on September 1, 2021.
Although the development of hypersonic flight systems has existed for decades, it has now become the top priority of US national defense, bringing this field into a state of rapid growth and change. As a unique multidisciplinary field, the challenge is to find experts with the necessary skills to promote its development. However, when there are not enough experts, it creates an innovation gap, such as putting design for manufacturability (DFM) first in the R&D phase, and then turning into a manufacturing gap when it’s too late to make cost-effective changes .
Alliances, such as the newly established University Alliance for Applied Hypersonics (UCAH), provide an important environment for cultivating the talents needed to advance the field. Students can work directly with university researchers and industry professionals to develop technology and advance critical hypersonic research.
Although UCAH and other defense consortia authorized members to engage in a variety of engineering jobs, more work must be done to cultivate diverse and experienced talents, from design to material development and selection to manufacturing workshops.
In order to provide more lasting value in the field, the university alliance must make workforce development a priority by aligning with industry needs, involving members in industry-appropriate research, and investing in the program.
When transforming hypersonic technology into large-scale manufacturable projects, the existing engineering and manufacturing labor skill gap is the biggest challenge. If early research does not cross this aptly named valley of death—the gap between R&D and manufacturing, and many ambitious projects have failed—then we have lost an applicable and feasible solution.
The US manufacturing industry can accelerate the supersonic speed, but the risk of falling behind is to expand the size of the labor force to match. Therefore, the government and university development consortia must cooperate with manufacturers to put these plans into practice.
The industry has experienced skills gaps from manufacturing workshops to engineering laboratories-these gaps will only widen as the hypersonic market grows. Emerging technologies require an emerging labor force to expand knowledge in the field.
Hypersonic work spans several different key areas of various materials and structures, and each area has its own set of technical challenges. They require a high level of detailed knowledge, and if the required expertise does not exist, this may create obstacles to development and production. If we do not have enough people to maintain the job, it will be impossible to keep up with the demand for high-speed production.
For example, we need people who can build the final product. UCAH and other consortia are essential to promote modern manufacturing and ensure that students interested in the role of manufacturing are included. Through cross-functional dedicated workforce development efforts, the industry will be able to maintain a competitive advantage in hypersonic flight plans in the next few years.
By establishing UCAH, the Department of Defense is creating an opportunity to adopt a more focused approach to building capabilities in this area. All coalition members must work together to train the students’ niche capabilities so that we can build and maintain the momentum of research and expand it to produce the results our country needs.
The now-closed NASA Advanced Composites Alliance is an example of a successful workforce development effort. Its effectiveness is the result of combining R&D work with industry interests, which allows innovation to expand throughout the development ecosystem. Industry leaders have worked directly with NASA and universities on projects for two to four years. All members have developed professional knowledge and experience, learned to cooperate in a non-competitive environment, and nurtured college students to develop to nurture key industry players in the future.
This type of workforce development fills gaps in the industry and provides opportunities for small businesses to innovate quickly and diversify the field to achieve further growth-conducive to U.S. national security and economic security initiatives.
University alliances including UCAH are important assets in the hypersonic field and defense industry. Although their research has promoted emerging innovations, their greatest value lies in their ability to train our next generation of workforce. The consortium now needs to prioritize investment in such plans. By doing so, they can help foster the long-term success of hypersonic innovation.
About the author: Kim Caldwell leads Spirit AeroSystems’ R&D program as a senior manager of portfolio strategy and collaborative R&D. In her role, Caldwell also manages relationships with defense and government organizations, universities, and original equipment manufacturers to further develop strategic initiatives to develop technologies that drive growth. You can contact her at kimberly.a.caldwell@spiritaero.com.
Manufacturers of complex, highly engineered products (such as aircraft components) are committed to perfection every time. There is no room for maneuver.
Because aircraft production is extremely complex, manufacturers must carefully manage the quality process, paying great attention to every step. This requires an in-depth understanding of how to manage and adapt to dynamic production, quality, safety, and supply chain issues while meeting regulatory requirements.
Because many factors affect the delivery of high-quality products, it is difficult to manage complex and frequently changing production orders. The quality process must be dynamic in every aspect of inspection and design, production and testing. Thanks to Industry 4.0 strategies and modern manufacturing solutions, these quality challenges have become easier to manage and overcome.
The traditional focus of aircraft production has always been on materials. The source of most quality problems may be brittle fracture, corrosion, metal fatigue, or other factors. However, today’s aircraft production includes advanced, highly engineered technologies that use resistant materials. Product creation uses highly specialized and complex processes and electronic systems. General operations management software solutions may no longer be able to solve extremely complex problems.
More complex parts can be purchased from the global supply chain, so more consideration must be given to integrating them throughout the assembly process. Uncertainty brings new challenges to supply chain visibility and quality management. Ensuring the quality of so many parts and finished products requires better and more integrated quality methods.
Industry 4.0 represents the development of the manufacturing industry, and more and more advanced technologies are needed to meet strict quality requirements. Supporting technologies include Industrial Internet of Things (IIoT), digital threads, augmented reality (AR), and predictive analytics.
Quality 4.0 describes a data-driven production process quality method involving products, processes, planning, compliance and standards. It is built on rather than replacing traditional quality methods, using many of the same new technologies as its industrial counterparts, including machine learning, connected devices, cloud computing, and digital twins to transform the organization’s workflow and eliminate possible products or processes Defects. The emergence of Quality 4.0 is expected to further change the workplace culture by increasing reliance on data and a deeper use of quality as part of the overall product creation method.
Quality 4.0 integrates operational and quality assurance (QA) issues from the beginning to the design stage. This includes how to conceptualize and design products. Recent industry survey results indicate that most markets do not have an automated design transfer process. The manual process leaves room for errors, whether it is an internal error or communicating design and changes to the supply chain.
In addition to design, Quality 4.0 also uses process-centric machine learning to reduce waste, reduce rework, and optimize production parameters. In addition, it also solves product performance issues after delivery, uses on-site feedback to remotely update product software, maintains customer satisfaction, and ultimately ensures repeat business. It is becoming an inseparable partner of Industry 4.0.
However, quality is not only applicable to selected manufacturing links. The inclusiveness of Quality 4.0 can instill a comprehensive quality approach in manufacturing organizations, making the transformative power of data an integral part of corporate thinking. Compliance at all levels of the organization contributes to the formation of an overall quality culture.
No production process can run perfectly in 100% of the time. Changing conditions trigger unforeseen events that require remediation. Those who have experience in quality understand that it is all about the process of moving towards perfection. How do you ensure that quality is incorporated into the process to detect problems as early as possible? What will you do when you find the defect? Are there any external factors causing this problem? What changes can you make to the inspection plan or test procedure to prevent this problem from happening again?
Establish a mentality that every production process has a related and related quality process. Imagine a future where there is a one-to-one relationship and constantly measure quality. No matter what happens randomly, perfect quality can be achieved. Each work center reviews indicators and key performance indicators (KPIs) on a daily basis to identify areas for improvement before problems occur.
In this closed-loop system, each production process has a quality inference, which provides feedback to stop the process, allow the process to continue, or make real-time adjustments. The system is not affected by fatigue or human error. A closed-loop quality system designed for aircraft production is essential to achieve higher quality levels, shorten cycle times, and ensure compliance with AS9100 standards.
Ten years ago, the idea of ​​focusing QA on product design, market research, suppliers, product services, or other factors that affect customer satisfaction was impossible. Product design is understood to come from a higher authority; quality is about executing these designs on the assembly line, regardless of their shortcomings.
Today, many companies are rethinking how to do business. The status quo in 2018 may no longer be possible. More and more manufacturers are becoming smarter and smarter. More knowledge is available, which means better intelligence to build the right product in the first time, with higher efficiency and performance.