Chasing performance with additive manufacturing

A cross section of a turbine combustor
A cross section of a turbine combustor

Jon Porter, European business development director at VELO3D looks at how 3D printing affects the intriguing intersection of history, design intent, and technological hurdles common to the aerospace and Formula One racing industries.

 

Despite the unimaginable hardships of World War II, the manufacturing industry did learn - often the hard way - how to design and assemble products in far less time than before the global conflict. Aerospace engineers in particular developed the talent and skills needed to quickly produce fast, fuel-efficient engines and aerodynamic yet lightweight structures - even in very low quantities.

Jon Porter, European business development director at VELO3D
Jon Porter, European business development director at VELO3D

After the war, some of these engineers channelled their abilities in what many might consider an unusual direction: Formula One racing. In fact, most enthusiasts point to the Fédération Internationale de l'Automobile's (FIA) rules standardisation in 1946 as the birth of Formula One, with the first official event occurring just one year later.

It was during this time that former aerospace engineers began building lightweight cars to race on retired wartime airfields. The now legendary Silverstone Circuit here in the UK, for example, is built on the site of a Royal Air Force bomber station. It hosted the 1948 British Grand Prix, followed by the FIA-sanctioned World Championship of Drivers in 1950. Formula One was off to a flying start.

It’s not surprising. Fast cars and fast planes have a great deal in common. Both require powerful engines and the ability to endure extreme operating conditions for extended periods of time. The chassis, fuselage, and drivetrain - indeed everything about these vehicles and their many components - must be strong yet “with added lightness”, often made from materials that are difficult to manufacture via conventional means. In short, engineers in both industries chase performance in all its many forms, whatever the cost, convention be damned.

That’s why additive manufacturing (AM) received such a warm reception several decades ago, especially following the arrival in the last ten years or so of industrial-grade laser powder bed fusion (LPBF) metal AM. Suddenly designers of all teams could think about consolidating dozens of individual components into a single 3D printed metal structure, one boasting lower manufacturing costs, greatly accelerated development cycles, and far less weight than their legacy counterparts. For aircraft and race car makers alike, this progress meant taking their wares farther and faster than ever before. Unfortunately, the promise of AM all too often exceeded reality.

As is also the case with more traditional machining, casting, and plastic injection moulding, there remain a significant number of rules and constraints saddling most currently available LPBF systems. These include the need for extensive support structures, or anchors, to keep parts from distorting during the build process. Thin walls can also be problematic, as are process repeatability, consistent part accuracy, and predictable metallurgical properties. In addition, manufacturers must often make multiple test builds to "dial in" the build parameters, driving up project costs and extending lead-times.

Granted, metal AM - regardless of its constraints - offers far greater design freedom than many other manufacturing methods, and is therefore an increasingly important technology. But if the 3D printer and its supporting systems are unable to accomplish the designer’s full vision, that value proposition is limited. Workarounds ensue, frustration mounts and eventually the designer settles for less optimal components.

AM for design

It doesn’t have to be this way. Newer, advanced metal AM systems eliminate much of the Design for Additive Manufacturing (DfAM) pain felt by far too many in this industry. This next generation of metal 3D printers practically guarantees first-time build success. Part accuracy increases, just as correct and consistent metallurgical properties are assured. And while support structures are sometimes retained, they are minimal, easy to apply and easy to remove, thus simplifying the build process and reducing secondary post-processing costs. 

Advanced AM technology promises to democratise manufacturing
Advanced AM technology promises to democratise manufacturing

With such advanced capabilities, design engineers now have the freedom to overcome the constraints outlined earlier. Rather than designing for AM, they now have access to what I like to call “AM for design.” Aerospace firms and Formula One teams will certainly benefit from these systems, but so will any designer, manufacturer, or supplier who has previously had to sacrifice product performance in the name of DfAM.

Of course, success in these and other industries requires much more than highly capable metal AM systems. Engineers also need a fixed set of performance criteria that they can design against. They need 3D-printed material properties, approved processing parameters and application guidelines, failure modes and stress-strain thresholds, and all the other technical information available to traditional manufacturers. They need Design Allowables.

The aviation industry refers to this information as an MMPDS handbook, short for Metallic Materials Properties Development and Standardisation. It’s considered to be the most reliable source of aircraft materials data for aerospace materials selection and analysis. Unfortunately, the development of these standards requires significant investment, one that few AM equipment manufacturers are willing to make. It’s only those who are confident in their machinery and processes, and whose aim is the ability to transfer a single build file from machine to machine and produce an identical part each and every time, regardless of where or when it is built - these are the companies that are taking metal AM to the next, much-desired level.

An innovation combination

That’s because it’s the combination of MMPDS and advanced AM technology that will ultimately drive down cost and increase accessibility of metal 3D printing, making it the preferred process for volume manufacturing of parts that were once the stuff of designer’s dreams. It will also simplify the flight certification and approval process for 3D-printed components, not only for production uses but those required for MRO, saving the aircraft and automotive industries countless pounds in tooling costs, lost time, and waste.  

It’s an exciting time, to be sure. Advanced AM technology promises to democratise manufacturing in ways that were once thought impossible. It will level the playing field, allowing engineers to design parts with less concern over build constraints or whether the finished products will pass metallurgical muster. Moreover, the ability to print parts anywhere will serve to make manufacturing a more localised process, but one with a global reach. Perhaps best of all, this holds just as true for the aerospace and Formula One giants as it does the smallest of suppliers and design firms. Advanced metal AM, it seems, is becoming the great equaliser.

www.velo3d.com

Company

Velo3D [**]

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