The educational value of 3D printing cannot be ignored as academic institutions throughout the world are integrating additive workflows into existing curriculums. While many places of higher learning are just starting to catch on to the benefits of 3D printing, some schools have gotten a head start, giving students an advantage in the new additive workflows that will become standard for a range of industries.
One prime example is David Sheffler's "Jet Engine Manufacturing" course that has been taught at the University of Virginia since 2011.
Sheffler's class may be the first of its kind to have students build a working, one-quarter-scale replica of a Rolls-Royce AE3007 turbofan jet engine (found on the Air Force's RQ-4 Global Hawk UAV).
Ten years ago this sort of class project might have been impossible, but due to a combination of factors such as easy-to-learn software tools, affordable 3D printers, and the numerous engine blueprint schematics that can be found online, Sheffler and his students were able to break down the AE3007 part-by-part and recreate the engine at 1/4 scale.
To initiate the project, Sheffler gave the students 43 CAD (computer-aided design) files representing the various components of the AE3007. The students could not simply print the parts out to build the engine. Sheffler required his students to use real-world aerospace manufacturing tolerances. In order to meet those tolerances many of the parts had to be machined after printing for the final engine assembly to work. The goal was to have students treat the plastic, printed parts as if they were metal and bring the classroom in line with real-world manufacturing processes.
Mind you, this engine is not flight worthy (if you ignited fuel within the thermoplastic replica it would, of course, melt) but Sheffler's class illustrates how the most sophisticated mechanisms can be recreated with a 3d printer and current software tools. As additive metal manufacturing sees increased industry growth it will only be a matter of time for the real engines themselves to be manufactured completely by additive means. For example, it is GE's hope that their LEAP engine will consist of, almost entirely, additive parts in about 10 years.
Since 2011, Sheffler's class has created variations in the initial jet engine design. In 2012 and 2013, students explored turbo prop and turbo jet designs. The most recent class added a working air compressor. This design evolution would not be possible without 3D printing. If students were to build an engine using traditional means, it would set Sheffler back $250,000, a huge sum for a university class. Instead Sheffler's engine project cost $3000 – an affordable price made possible with the department's Stratasys Fortus 400mc.
The engine itself actually spins at 2000 RPM. For testing and design the students used- a combination of Solidworks and Autodesk Inventor. With Autodesk Inventor, the class uses finite element analysis (FEA) to test the stiffness and stress of an added copper manifold (one of the only non-3D printed parts on the engine). Also, some of plastic parts are analyzed using FEA and given the properties of titanium to test out the replica as if it were a real engine.
Sheffler's engine class caught the attention of Mitre, which asked if it was possible to 3D print something that was flight worthy. More specifically, could Sheffler and his class 3D print a UAV (unmanned aerial vehicle).
Put to test, Sheffler and his students took on the challenge to create a flight worthy UAV for under $5000. Sheffler's UAV design was based on the army's Raven. The army's version cost $35,000. By leveraging 3d printing, off-the-shelf equipment, the Android operating system, servos, and batteries (nothing was special ordered) Sheffler's version cost $2000.
The intended purpose for Sheffler's UAV will be agriculture and water monitoring. If all goes as planned it will be an autonomous system for agricultural research with a spectral testing system to analyze chlorophyll, algae plumes and other ecological issues.
The project has been in ongoing development for two years in consortium with various agencies in Virginia beach. Mitre played a supporting role funding the project, which has become a summer job for Sheffler's independent study students.
Aerospace manufacturers in need of talent should take notice of Sheffler's students. With their hands-on knowledge of 3D printing, they are poised to become industry leaders for the future of aerospace additive manufacturing.