Creating products that deliver performance efficiencies is a top priority for manufacturers and the industries they serve who are putting a greater emphasis on green credentials. The aerospace industry is at the forefront, looking for opportunities to innovate with novel designs that ultimately help improve fuel efficiency. Additive manufacturing (AM) technologies are augmenting manufacturing workflows, transforming the way these design innovations are produced.

AM is a revolutionary technology that is changing the way many companies are designing and producing products – with the aerospace industry being a clear leader. As a tool, AM enables designers and engineers to create parts that cannot be expressed with traditional formative and subtractive methods. With AM, there is low correlation between complexity and cost – allowing engineers to design for function – utilizing Design for Additive Manufacturing (DfAM) philosophies. As a digital technology, AM also helps improve efficiency as traditional tooling is not required. This allows design teams to iterate rapidly, achieving a superior product faster than would be possible with formative tools and a subtractive method.

In aerospace, this rapid, minimally constrained design environment allows for step changes in design optimization. At a practical level, this is now enabling aerospace companies to design better, faster and more efficient platforms. Here are several significant advantages the aerospace industry can gain as a result of embracing the combined DfAM/AM approach to manufacturing.

Thales Alenia bracket for satellite antenna produced in Titanium using Direct Metal Printing resulted in a 25% lighter part than a traditionally manufactured bracket.

1. Design Simplification, Component Consolidation and Part Count Reduction

Historically, complexity, cost, time-to-market as well as end system reliability hold a close correlation to the number of subcomponents within an assembly. The fewer parts you have, the less assembly required and ultimately, the fewer points of failure. While a reduction in the number of parts as a design philosophy is not new, nor even exclusive to additive manufacturing, AM allows engineers to take it to a whole new level.

My favorite recent example was a direct metal component that was traditionally made from 12 separate castings and tubes, all welded into a single part. Aside from assembly labor, tools, jigs and fixtures – as well as a complex multi-vendor supply chain – it ultimately contained a quality control (QC) step where nearly 10 meters of weld lines had to be meticulously CT inspected for defects. When AM was applied, 12 parts became one – and jigs and fixtures, assembly and slow QC inspection of weld lines were no longer required. The resultant part was lighter, had fewer points of failure, was more cost-effective and efficient to source and produce, and yielded better performance.

2. Thermal Transfer

The fuel efficiency of jet engines is a function of multiple factors. One of these factors is system temperature. Typically, the hotter you can run the system, the more fuel-efficient it becomes. A 100-200°C increase in temperature can account for a 1-2 percent efficiency increase.

While that does not sound like much, it can equate to hundreds of millions of dollars in fuel savings for an airline when you look at thousands of engines flying many thousands of hours. Additive manufacturing allows engineers to integrate the design of exotic/conformal cooling structures into sub-components that ultimately allow the parts to maintain functional and structural integrity at these elevated temperatures.

Exhaust manifold traditionally made from multiple components can be designed and produced more efficiently as a single part for additive manufacturing. The AM part does not require tooling, does not require assembly and joint inspection, has fewer points of failure, is lighter, and yields better performance.

Similar principals of thermal transfer exist within rocket combustion systems, where temperature drives pressure. This, in turn, yields performance, as well as the rate of wear-and-tear/ablation, feeding the trend towards system reuse economics.

Practicing the principals of thermal transfer is occurring at the university level, enabling engineering students to iterate their designs and gain invaluable hands-on experiences that will serve them well in the field. Last summer, members of Stanford University’s Student Space Initiative completed a major liquid rocket project that required them to rethink their stainless prototype engine, which needed to withstand 4000° temperatures and still deliver optimal performance. With help from 3D Systems’ team, engineering students took advantage of a transition to nickel super alloy (IN718) plus advanced DfAM to yield a monolithic structure that achieved part count reduction, which required no assembly. The result was a successful full-burn duration of the engine, which surpassed previous power records.

3. Weight Reduction

Additive manufacturing holds huge potential benefits for the efficiency of spacecraft and satellites. Reducing the weight of parts that fly always yields improved fuel efficiency and performance. However, nowhere is this improvement realized more than space systems.

Hypersonic nozzle produced using additive manufacturing maintains functional and structural integrity at elevated temperatures.

Design-driven structural optimization, both manual and automatic, yields step changes in strength-to-weight ratios. Recent examples include Thales brackets for satellite antenna. Utilizing advanced structural algorithms, Thales was able to generate a bracket design that, when expressed in Direct Titanium printing, was 25 percent lighter, while maintaining the performance of a traditionally manufactured bracket. Further opportunities for optimization were identified based on transitioning to tubular structures, as we see in bicycle frames.

When it comes to strength-to-weight design efficiencies, tubular structures reinforced with integrated internal lattice (i.e., metallic foam) represent a significant opportunity for step changes in performance. Applications include: orbital lift, low inertia maneuverability in UCAV and missile systems, and systems requiring rapid acceleration and deceleration. To achieve that objective AM enables tubular structures for component design (e.g., brackets). Inspired by a bird’s bone structure, tubular architectures provide the performance needed, and when using titanium, do it to maximum effect.

Additive Manufacturing, the Efficiency Break-through

When you combine thermal transfer, component consolidation, and weight reduction, you can see how additive manufacturing has a large part to play in improving energy usage, efficiency and performance figures for the aerospace market. There are other benefits too, such as rapid iteration cycles leading to rapid time to deployment, low rate initial production (LRIP) design flexibility (Launch & Iterate), lean “on demand manufacturing” supply chains, sustained spares supply and legacy support.

As adoption of AM in the aerospace industry continues to accelerate, so too will the number of manufacturers utilizing AM as a standard mode of manufacture. AM is transforming how industry-leaders are creating new, improved products while gaining efficiencies that enable the step changes in performance required for future platforms to compete on the global stage.

This article was written by Patrick Dunne, Vice President, Advanced Application Development, 3D Systems (Rock Hill, SC). For more information, visit here .

Aerospace Manufacturing and Machining Magazine

This article first appeared in the December, 2020 issue of Aerospace Manufacturing and Machining Magazine.

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