Evolving Aerospace Design Drives Advanced Material Development in Additive Manufacturing

By Regina Pynn and Jaime Tringale

As the aerospace industry continues its upward recovery, next- generation aircraft design continues to push forward with higher expectations than ever. New aircraft should be lighter, faster, safer, stronger, and of course, more cost-effective than those that they are replacing. The macro-trends in aviation are driving technology advancement for even the smallest parts in flying vehicles.

Aerospace vehicles require every component be optimized for weight, performance, and functionality. Additive Manufacturing, or 3D printing, has made a name for itself in the first two areas. With complexity decoupled from manufacturing cost, intricate parts can be designed to reduce weight without sacrificing performance in ways that traditional manufacturing methods cannot match. The performance capability of additively manufactured parts has been validated with increasing adoption on aerospace platforms, including Boeing’s CST-100 spacecraft. But what is the role for additive manufacturing when it comes to presenting multi-functional part solutions? What more can be asked of a simple bracket or close-out panel beyond the mechanical and environmental performance of the incumbent materials? Can we make the components multi-functional?

Hexcel brought together its additive manufacturing HexAM® team and its RF Interference Control Products team to look at multifunctional 3D-printed components that meet aerospace requirements. The result of that collaboration was HexPEKK® EM which enhances the electromagnetic properties of the proven HexAM® technology. As the latest addition to the HexPEKK® material portfolio, HexPEKK® EM provides the capability to additively manufacture multifunction production parts that meet both mechanical and electromagnetic performance requirements.

Electromagnetic Interference and RF Absorption

Complex electronic systems across the aerospace and defense industries continue to improve in performance and capability while operating at more frequency ranges than ever before. While increased performance is beneficial to the overall aircraft, electromagnetic interference (EMI) has become an increasing concern. EMI can stem from internal and external sources and electronic components can cause a considerable amount of unwanted interference within the aircraft. EMI poses a risk to the effectiveness of electronic systems, which can cause malfunctions or failures at various levels. With increasing compliance and safety regulations, EMI mitigation should be considered at the time of design. HexPEKK® EM improves the EMI performance of the existing HexPEKK® materials. Housings, brackets, and panels neighboring electronic systems manufactured with HexPEKK® EM can serve as a means to aid in the mitigation of EMI while taking advantage of the design freedom and weight savings advocated by additive manufacturing.

Low Resistivity

Management of static electricity buildup is an important consideration for primary and secondary structures in aviation applications. Low resistivity materials are necessary in aircraft assemblies due to build-up of static electricity caused by normal flight operation. Grounding considerations are essential in areas of sensitive electrical equipment. When static electricity builds up and is released, there is a shock as the electricity transfers, which can be hazardous to aircraft causing potential damage to sensors, processors, and other components critical to flight operation. Management of electrical discharge has been an obstacle to composite adoption for some applications. Hexcel’s flagship additive material, HexPEKK®-100, includes carbon in its formulation specifically to provide electrostatic discharge (ESD) requirements. Hexcel’s latest material offering, HexPEKK® EM, goes even further with a resistivity that is more than three orders of magnitude lower than HexPEKK®-100. HexPEKK® EM maintains all the advantages of high-performance 3D-printed PEKK thermoplastic making it suitable for many components on aerospace systems.

Conclusion

The next generation of aviation platforms will demand that each material and piece of hardware justify its place on increasingly small and lightweight platforms. Additive manufacturing technologies that are grounded in sound structural principles and also include multi-functional capabilities will have an increasing role to play in this design revolution.

About the Authors

Regina Pynn
Regina has over a decade of experience in aerospace owning the engineering, fabrication, testing and qualification of complex engineered systems. She has led development through LRIP/Entry Into Service activities for hydromechanical and electromechanical control systems on commercial and defense platforms. In 2017 she joined the Aerospace and Defense division of OPM as Program Manager and remained in that role when OPM was acquired by Hexcel. Today she leads Material and Process Engineering and the Program Management teams at Hexcel’s additive manufacturing plant in Hartford, CT. She holds a B.E. in Mechanical Engineering and an M.E. in Systems Engineering from Stevens Institute of Technology.

Jaime Tringale
Jaime has been with ARC Technologies, a Hexcel company, since 2014 and has served various roles across sales and marketing. She currently serves as the International Business Manager for our RF Interference Control products. She has a BBA degree in Marketing from the University of Massachusetts Amherst.

Article Reference Links: 
Reuters CST-100 article
FFA Concept of Operations for UAM 
Boeing briefer on aviation vibration 
Acousti-Cap 
Honeycomb 
RF Interference Control 
Additive Manufacturing