Turning 10,000 AM parts into full-scale production at GA-ASI

General Atomics Aeronautical Systems, Inc. (GA-ASI) is a leading designer and manufacturer of Remotely Piloted Aircraft (RPA) systems. In a talk at the AMUG 2023 Conference—one of the most captivating among several great presentations—GA-ASI’s Additive Manufacturing Department Manager Steve Fournier revealed exactly how deep GA-ASI’s commitment to AM goes, from polymer (FDM, SLS), to metal (L-PBF, DED-W), to composite tooling (LSAM, BJP). The next step is full workflow integration via a collaboration with the experts and pioneers at Divergent, to implement their DAPS capabilities. “The future of AM,” Fournier said, “is bright”.

AM-centric

In 2021 General Atomics Aeronautical Systems established a new Center of Excellence for Additive Design and Manufacturing (AD&M). The Center is focused on rapid-reaction manufacturing of GA-ASI’s line of Unmanned Aircraft Systems (UAS) using fully functional and flight-ready additive manufacturing applications, research and development, large-scale tooling and next-generation flight hardware.

Over the past decade, GA-ASI has invested in the onboarding of AM technologies, as well as leading the formation and rapid growth of a dedicated department five years ago. Fournier explained that the centralization of AM activities has proven to be a strong catalyst for AM adoption, leading to successful initiatives in AM technology insertion, application industrialization, flight hardware manufacturing, risk reduction for R&D and knowledge transfer.

GA-ASI has qualified over 350 flight components across the different AM modalities used for production. To develop and qualify flight-capable AM applications, the company is expanding its AM ecosystem, which is composed of the key elements required for bringing an AM application from a prototype stage (print right once) to a production-level stage (print right always).

Mr. Fournier revealed that GA-ASI is now additively manufacturing about 7,500 parts per year. Overall, on their latest UAS platform, the MQ-9B SkyGuardian, the company has saved over $2 million in tooling costs and over $300,000 per aircraft in recurring cost avoidance (with approximately 240 AM parts on that aircraft platform). The number of AM applications continues to grow rapidly, fueled by the AM ecosystem, with more than 10,000 additively manufactured components on the aircraft it has produced. In particular, the MQ-9B SkyGuardian and SeaGuardian models are leading the industry in the use of AM parts. In total, AM components already registered over 300,000 combined flight hours.

“GA-ASI is continually looking for ways to enable, accelerate and integrate Additive Manufacturing technologies into our designs, our operations and our products,” explained GA-ASI President David R. Alexander. “Through our AD&M Center of Excellence, we’re using a structured and stringent qualification process for AM applications that deliver a positive business case for us over conventional manufacturing methods. Through a comprehensive and holistic approach, our team of AM professionals are working to increase the adoption of AM parts for the benefit of our aircraft and ultimately, our customers.”

A foundation for the future

GA-ASI’s AM ecosystem has enabled the advancement of repeatable and reliable production-grade 3D printing within the company, but this is not as easy as it may seem. The foundational ecosystem for AM at GA-ASI is based on a dozen different elements, ranging from material allowables and equivalencies to R&D and CapEx funding.

This has been supplemented by ecosystem-controlled processes, the establishment of an applications team, and a well-defined expansion roadmap. GA-ASI performs some recurring production activities at its AD&M Center of Excellence, but the demand for rapid-reaction and low-rate manufacturing has required the development of a strong AM manufacturing supply chain for the overflow production of complex end-use thermoplastics and metal parts.

As Fournier explained, “The depth of the AM ecosystem is specific to each AM application and is driven by [aspects such as] application mission criticality, qualification requirements from the airworthiness authority, QA/process control availability and application track record.”

More specifically, the use of AM in GA-ASI’s product lifecycle starts very early, even before the product is even conceived. At a purely business analysis level it helps to increase P-win. In the concept phase it helps to accelerate time to market. In the design phase it also enables high integration. Coming to the actual prototype, it enables tool-less manufacturing. When it comes time to move into production, AM plays a key role in reducing costs for LRIP (low-rate initial production), also via tool-less manufacturing and high level of integration. For many of GA-ASI’s products, these benefits continue to be applied at full production scale, resulting in improved system availability, and especially in the sustainment of existing products during their life cycle. The higher the integration and part complexity, the clearer the AM’s value proposition becomes. Today AM represents about 1% of the bill of materials (BOM): the goal is to grow to 5% BOM on larger platforms and as much as 30% to 90% of BOM on small UAS.

Getting down to the AM

What does it all come down to in terms of the types of AM parts produced? Looking at polymer AM technologies, exclusively thermoplastic-based, FDM is used primarily for part consolidation and substitution. This means replacing laminate parts, creating large conformal air management systems, lamination tooling and adapted ground control equipment. Future applications will include fuel compatible (i.e. chemically resistant) materials as well as continuous fiber-reinforced 3D printed parts for metal replacement applications.

Polymer PBF applications (for now only SLS) also include laminate part conversions while also leveraging the technology’s greater geometric freedom for complex manifolds, conformal tooling and large ducting assemblies. Future development will look at increasingly large assemblies. A particularly interesting application is the collaboration with Hexcel to leverage HexAM technology for the selective laser sintering of PEKK-based composites (originally developed by Oxford Performance Materials) for the production of outer and inner mold lines (OML and IML). The complex geometries enabled by AM provided design freedom and an easier manufacturing process to improve the performance and operation of UAV systems.

In metals, LPBF is also primarily seen as a solution for parts consolidation and substitution, with applications in laminate-to-AM conversions, integrated fluid manifolds, OML (outer mold line) fairings, as well as engine and exhaust components. Another very interesting application is seen in integrated heat exchangers (HX). GA-ASI partnered with Conflux Technology on the design and manufacture of a new Fuel Oil Heat Exchanger (FOHE) for its MQ-9B SkyGuardian and SeaGuardian. Altogether the two companies have worked on four different AM projects since 2018 and most recently developed a cold plate heat exchanger that provides additional cooling capacity for the high-dissipation Line-Replaceable Unit (LRU) used in various GA-ASI’s UAS platforms. The way forward for metal L-PBF applications consists of larger consolidations, integrated gimbles and more space applications.

Metal DED technology, which uses wire as feedstock, is seen as a potential key enabler for making large parts at significantly reduced costs. GA-ASI has been working on completing the AM ecosystem qualification for titanium class A & B components and on supplier qualification in collaboration with Norsk Titanium. Other DED partners include Lincoln Electric for applications focused on complex INVAR and steel lamination tooling. Future growth is targeting additional Inconel applications.

Many current AM applications at GA-ASI (mainly for tooling) also focus on large-format 3D printing technologies both in composites (LSAM) and sand (binder jetting). LSAM parts, such as those produced by Thermwood, are used for RT mill fixtures for composite laminate but also for some large-scale end-use assemblies, such as ground applications measuring up to five meters in length. In the future, the size of these parts could grow to lengths of six to 13 meters. Sand binder jetting systems are used for up to 2X-3X cost savings on tooling and washout, with the future goal of producing masters and increasingly customized printers to meet specific requirements.

AM is not the end goal (digital design and manufacturing is)

As everyone involved with AM knows very well, the implementation of a fully digital end-to-end manufacturing process that includes AM at its core is filled with challenges that still need to be overcome. The workflow must begin with design for function/AM/assembly, continue through printing and finishing, go on to rapid part inspection and quality and finally implement process integration to achieve full automation.

To address many of these challenges, GA-ASI formally partnered with Divergent Technologies, Inc. The company has developed a data-driven approach to design, fabricate and assemble vehicle structures called the Divergent Adaptive Production System (DAPS). GA-ASI is now looking to qualify and implement this capability to some of its UAS platforms.

The joint development program began in 2022 and led to a stronger strategic partnership on multiple platforms. The companies have already completed two projects leading to a fully integrated small (<500 lbs.) UAS aerostructure, leveraging model-based, AI-driven and topology-optimized designs. The integrated metal structure was 3D printed (with printing times below 13 hours per node), which led to the reduction of the part count integration by over 95% while meeting weight targets.

The DAPS process inspected each printed component by creating a full digital twin of the small UAS (SUAS) that was then applied to a fully automated, tool-less robotic assembly process that took less than 20 minutes to complete. This process enabled the team to go from a print-ready SUAS design to a fully assembled deliverable airframe in less than two days. GA-ASI anticipates this capability will enable near-theater ramp capacity in the future to support the warfighter.

This innovative approach to design and manufacturing leads to highly integrated weight and performance-optimized designs that are naturally, but not exclusively, leveraging AM technologies at a substantially lower airframe recurring cost, while providing a rapid tool-less iterative design approach for multiple platform variants. “Industrial production-level AM is possible for defense and civilian UAS, with a proper ecosystem applied to AM use,” Fournier concluded, “however, AM should not be the end goal but rather an enabling technology suite supporting a fully digital manufacturing process workflow.”