An inherent advantage of Stratasys 3D printing is
the ability to design beyond surface geometry.
While the design of internal structures now has a
much higher level of design freedom, it can be
in initiating engineering structures for aerospace.
Collaborating with Stratasys on the design enabled
Aurora to utilize topology optimization, a physics-based approach that replicates complex structures
found in nature, and show where internal material
is unnecessary and optimize the structure for a
For Aurora, Stratasys’ additive manufacturing
technology gave the team the design optimization
to produce a stiff, lightweight structure, while
also enabling the cost-effective development of a
customized, mission-specific aircraft.
In addition, the ability to consolidate assemblies
into single components allows complex designs to
become elegant and simple solutions. An example
on this aircraft is the fuel tank that combines
multiple components by having tubing printed on
the inside and outside, mounts that attach to the
fuel filter and fuel pump, as well as small clamps to
attach the fuel lines.
This design freedom allowed engineers to very
accurately position the center of gravity, a key
parameter for blended wing body aircraft.
Dan Campbell, Research Engineer at Aurora Flight Sciences, said, “Any change in the design causes issues to the center of gravity. However, since the additive process can easily control where material is put and where it isn’t, iterating designs has minimal impact elsewhere on the aircraft.” The build time for this aircraft was cut in half by using additive manufacturing technologies. Eliminating the need for tooling helped reduce lead times significantly. The core team of six engineers used GrabCAD, a Stratasys collaboration solution that helps engineering teams manage, view and share CAD files, to coordinate the project. This helped the two companies, in two different locations, design and produce the aircraft in the short time frame. The software acts almost as a social media site, tracking revisions, allowing messaging, and acting as a repository for working engineering documents such as the Bill of Materials. 3D printing flight-ready parts The major parts of the aircraft include:
• Two winglets
• Payload module
• Fuel tank
• Thrust vectoring mechanism
It has a 9.5ft (2.9m) wingspan and an airframe weight of just 14lbs (6.4kg). It consists of 34 total components, 26 of which were 3D printed and make-up about 80% of the aircraft airframe by weight. Using Stratasys Fortus® 3D Printers, the wings and fuselage were produced in ASA thermoplastic, to give the necessary strength and stiffness, but with low density.
The team also took advantage of Stratasys Direct Manufacturing, a full- service custom manufacturing center, which offers multiple additive manufacturing technologies and almost every material currently available. The fuel tank was produced using Laser Sintering (LS) of nylon, the exhaust duct cover was 3D printed using ULTEM 1010 resin thermoplastic and the thrust vectoring duct by Direct Metal Laser Sintering (DMLS) of INCONEL 718, necessary because of the high exhaust temperatures up to 1300°F (700°C).Design freedom for aircraft innovation.