Lifting 3D Printing to New Heights

DMLS executes design configurations impractical for conventional machining to undertake.

Whether it’s through 3D printing jet engine fuel nozzles by the thousands or validating metal rocket injectors for space flight, aerospace has consistently proven itself to be on the cutting edge of the technology. 3D printing is making such an impact on aerospace manufacturing that Stratasys Direct Manufacturing CEO Joe Allison predicts that within 10 years every commercial aircraft will have 3D-printed parts on them.

Fused-deposition modeling ULTEM 9085 thermoplastics have been FAA certified for flight in multiple applications, from interior components to internal small ducting units.

Also known as additive manufacturing (AM), 3D printing is helping aerospace make these types of advancements on a nearly daily basis.

Like early adopters of revolutionary technologies in any industry, those in aerospace who first embraced 3D printing had initially placed emphasis on what the technology could do to build better parts. As aerospace has moved toward larger-scale adoption, other critical factors have come into play, including: recruitment and development of skilled talent, diversification in types of companies investing, and increased customization and complexity. All have an impact on expanding AM adoption across the aerospace industry.

The next wave of engineering talent

Today’s young engineers have grown up fluent in digital design programs, including CAD, and are already learning how to take advantage of AM rather than just converting traditionally manufactured parts into AM parts. They also seem to embrace the iterative design process afforded by AM when costly tooling and set up charges are not involved.

This shift represents something akin to a changing of the guard, with young engineers championing the technology as a process integral to a manufacturer’s production line.

The 2015 Wohlers Report highlights the importance of education and training for up-and-coming engineers, stressing that the earlier these designers are introduced to AM training and processes, the better, as this early exposure can help them think about designing parts specifically for AM vs. being boxed in by the limitations of traditional manufacturing.

While AM is a new concept in K-12 schools, colleges and universities have used the technology to support engineering, design, and other programs for years. However, the report also notes there’s a worldwide shortage of educational and training resources, which will have to be addressed for the technology to realize its full potential.

Diversification comes with standardization

Diversification is another major progression underway. While aerospace giants such as Boeing, NASA, and Airbus have been responsible for much of the industry’s early 3D printing innovation and production, we’re expecting to see an increasing amount of smaller players begin implementing the method into their manufacturing processes. 3D printing methods deliver high performance thermoplastics created via a process that allows for reduced program development costs and economically produce one-off and low volume parts–perfect for smaller manufacturer needs.

A couple key hurdles that that must be jumped for more companies to invest in 3D printing is standardization and FAA accepted design allowables. Efforts in developing the technology and process specifications are fragmented and have been the domain of larger aerospace companies. Since there is not yet an established guideline to ensure 3D-printing processes can reliably produce parts with consistent, known mechanical characteristics, there is still something of a “wait-and-see” approach for smaller companies when it comes to investing in 3D printing.

Additive manufacturing opens up new ways to think about designs and assemblies.

However, initiatives such as those through America Makes, ASTM, and SAE International are underway to develop terminologies, test methods, and process improvements; these standards will collaboratively help companies and users work under consistent 3D printing guidelines to consistently produce a well-defined product.

Complex and customizable parts

3D printing is that rare process that can significantly simplify intricate parts through consolidation, allowing multiple subassemblies to be combined into and built as a single component. This could cut down on the overall use of fasteners, adhesive, and welds, thus reducing potential failure modes associated with joints. This also minimizes assembly time and simplifies bill-of-material and inventory management, thereby decreasing costs and increasing productivity.

NASA’s exploration into 3D printing as an alternative manufacturing method for their rocket injectors is a prime example of how the technology has led to incredible reduction in manufacturing labor and time. Stratasys recently worked with NASA’s Marshall Space Flight Center on a functional prototype injector that originally contained 163 individual components, making them NASA’s most complex rocket engine parts ever designed. But with 3D printing, the team was able to create those same parts as two-piece functional prototypes that also passed hot fire, static, and strenuous mechanical property tests.

3D printing can also add complexity where it’s beneficial. Those who have drawn up parts on a drafting table can tell you that it’s much easier to create simple geometries made up of straight lines and circles; but simpler parts also simplified the fabrication methods needed to produce those parts. For example, when there are stress concentrations, engineers will often opt for using overall thicker stock material, sacrificing weight-savings. 3D printing could also allow growing localized strengthening features such as honeycomb lattice structures in those areas while at the same time removing material in sections with little or no load.

Airlines and completion centers are also realizing the customization benefits of 3D printing, which can create low volume parts at a much more cost-effective rate than traditional manufacturing. To get the aesthetic finishes these high-end applications demand, many customers and users turn to 3D printing processes such as DMLS (direct metal laser sintering) and SLS (selective laser sintering). They can also reach out to service providers who offer finishing techniques that provide a polished, smooth finish, in addition to creating parts through conventional and additive manufacturing methods.

These developments and innovations make for an exciting time in the aerospace industry. As 3D printing continues to become more widely adopted, and an increasing number of engineers are process champions, the next groundbreaking advancement is always just a day away. The technology makes the seemingly impossible, possible.

This article was written for Aerospace Engineering by Ed Yuh, Project Engineering Manager, Stratasys Direct Manufacturing.