Quality Considerations for Aerospace Manufacturing

Originally published on fastradius.com on July 6, 2020

Manufacturers who work with aerospace customers know that parts produced for aerospace applications are held to strict functional and regulatory requirements. Aerospace parts not only tend to be more specialized than parts created for applications in other industries; they are also more likely to be mission critical, meaning that failure would result in the loss of equipment and potential harm to operators, passengers, or bystanders. 

Engineers need to ensure that every part produced will perform consistently and reliably to the requirements of the application, which necessitates that components be held to rigorous standards, testing and inspection, in order to verify proper functionality and to ensure safety is prioritized. 

Aerospace projects tend to have higher budgets and longer development cycles, which typically means that more initial planning is involved to ensure the ultimate success of the project. This article will highlight a few key design and engineering considerations for aerospace parts that product teams are likely to encounter.

Regulatory requirements and vendor certification expectations

Because of the number of international, federal, and industry-specific regulations that stipulate how parts are made, aerospace companies generally work exclusively with suppliers and manufacturers who have the proper certifications.

One of the most widely used aerospace quality management standards is AS9100, which provides universal definitions and expectations for quality management of manufacturers designing, producing, and inspecting aerospace parts. The standard has gone through multiple versions over the years, the most recent being ASD9100D, which was released in 2016. 

Manufacturers who demonstrate that they are in compliance with ASD9100D can also demonstrate compliance with the broader ISO 9001 standard (which the AS9100 quality management system contains in its entirety). Manufacturers also need to consider ASA-100 certification, a standard that complies with FAA Advisory Circular 00-56, which provides a standardized quality system for civil aircraft parts distributors.

Functional requirements

Aerospace parts require a unique blend of properties. Many components need to be extremely strong and stiff — characteristics often associated with harder, heavier materials. However, reducing weight wherever possible is critical for nearly all aerospace manufacturing applications, which can also enable product teams to design parts with unique or complex geometries. It is common for manufacturers to go through iterations of design, engineering, and testing to ensure the part will function properly, meeting all functional requirements, while also optimizing to remove as much weight as possible from the part, without compromising performance. 

Additive manufacturing methods provide a significant advantage here because they enable the production of parts using the minimum amount of material necessary to satisfy the functional requirements of a component. 

Materials

The need for parts that are stiff and strong yet flexible and light has led to manufacturing aerospace components with materials like titanium, tungsten, and carbon fiber. However, many of these exotic materials react when they encounter one another, which can lead to galvanic corrosion or dissimilarities between coefficients of thermal expansion. Additive manufacturing methods again offer a unique alternative, as the vast majority of materials used in these processes are nonreactive and provide a broad range of material properties at lower densities than the aforementioned materials.

For decades, carbon fiber was viewed as a risky material for use in aerospace applications because of its incompatibility with certain metals, anisotropic properties, and its unique means of manufacture. As the means of manufacture matured and use cases for highly optimized geometries and material properties increased, the use of carbon fiber increased extensively in the aerospace industry. 

Today, carbon fiber is commonly found in many aerospace applications. Similarly, the technology used in additive manufacturing has changed so drastically in the past few years that there are now far fewer material restrictions for the parts that can be made through additive means. 

Additively manufactured parts are following a similar trajectory in aerospace applications, allowing engineers to control and optimize component geometries like never before. In addition to component weight reduction, the maturity of additive manufacturing technology and process control has allowed engineers to optimize component properties, like stiffness and strength, with the precision of traditional manufacturing methods. 

This is drastically increasing the use cases for additively manufactured parts within aerospace applications every year, and because of this, it is increasingly common to see additively manufactured parts filling the roles of components that were once traditionally manufactured in the aerospace industry.

Testing criteria

While all parts need to be tested to ensure their proper function, this is especially important for aerospace applications, as many of the components are critical parts. Many of these parts require specific mechanical properties and are key to ensuring safety, so it’s prudent for product teams to have their testing criteria defined early and in detail — before testing begins. Knowing what success looks like gives engineers clear benchmarks and allows designers to efficiently refine the part design against that target.

Risk mitigation

Aerospace customers will also likely want to see risk assessments. Due to the high number of critical parts used in aerospace applications, it’s vital that product teams feel confident that their parts are reliable and pose little to no risk to human health and safety. 

By using well defined risk analysis methodologies, like Failure Modes and Effects Analysis (FMEA), engineers can determine the various ways in which a part could fail, as well as the consequences associated with those failures, so product development teams can proactively mitigate risks. This helps teams determine the costs they’re willing to incur to ensure that certain failures never occur, which can, in turn, lead to further design changes or building in redundant systems to mitigate their effects. 

Powering aerospace with additive

While additive manufacturing isn’t going to be the best option for every application, the technology has advanced and matured in such a way that the number of potential applications in aerospace increases every year. In many cases, additive manufacturing allows for specific or complex parts to be made in purposeful ways to fulfill the strict requirements within the aerospace industry. 

Some critical parts will obviously be better suited to other manufacturing methods, but the speed and flexibility of additive technologies presents an increasingly economical option. Ultimately, engineers and product development teams should invest in robust preparation before starting production to ensure that their aerospace parts meet all necessary functional and regulatory requirements, are manufactured with the ideal materials, and are designed to mitigate risk. 

At SyBridge, we thrive on exceeding expectations, and we’re well-positioned to help product teams navigate the many considerations at play in any product development project. We’re a passionate team of designers and engineers looking to make lasting business partnerships that push at the boundaries of what’s possible through modern manufacturing. Our aerospace customers hold us to a higher bar not only for manufacturing, but for design and engineering advisement. Contact us today to get started.