ASME IAM3D Challenge Case Study: Applications of Additive Manufacturing for Unmanned Aerial Vehicle

By Joshua Olesker/ASME Public Information

Aaron Inouye of BYU (left) and Eli Cohen of Purdue (center) speaking with ASME President J. Robert Sims (right)

Eli Cohen of Purdue University and Aaron Inouye of Brigham Young University represented the multi-institutional team that won the Best Overall title at the November 2014 Innovative Advanced Manufacturing (IAM3D) Challenge in Montreal.  Watching them present you might not have guessed that before coming to Montreal to compete, the young engineers – the first a young faculty member, the second an undergraduate student – had never met in person.

“One major demand of engineering in this day and age is working around the globe,” said Inouye in a post-competition interview.  “Never meeting any of my teammates until after the project was done -- that was a challenge.  Yesterday was the first time that Eli and I were ever in the same room together.” 

Aaron Inouye of BYU and Eli Cohen of Purdue presenting at IAM3D Challenge Finals

The IAM3D Challenge calls on Mechanical Engineering and multi-disciplinary engineering undergraduates around the world to re-imagine existing products or create new designs to minimize energy consumption and/or improve efficiency by applying Additive Manufacturing technologies to their production.  To win, a team must demonstrate exceptional creativity and ingenuity as well as mastery of engineering design principles and their successful application.

Eli and Aaron’s team – made up of students and advised by faculty from Purdue and Brigham Young Universities – leveraged the opportunities of 3D-printing to produce an Unmanned Aerial Vehicle.  While UAVs, or “drones,” may be best known for their military use, potential civilian applications range from packaged-goods delivery to emergency medicine to weather monitoring and beyond. According to estimates cited in their team’s business case, the market for small UAVs is expected to expand to as much as $11 billion annually over the next decade. 

The Purdue/BYU aircraft itself

Till now, a significant barrier to this growth of the UAV market has been the high costs of conventional manufacturing.  But the Purdue/BYU team used Additive technology to eliminate that barrier.  “What we did with this aircraft allowed different people to contribute their different skills but still take the manufacturing out of the equation,” Cohen said. “People could spend all their time up in their brains, thinking ‘how can I make this a better product?’ And then we hit PRINT -- and we had it.”


The Aircraft

The Purdue/BYU UAV weighs 12lbs and is, according to Cohen and Inouye, the world’s largest 3D-printed aircraft.  Its purpose: to aid farmers in monitoring crop health over large areas quickly and with high accuracy.  The craft’s body combines additively manufactured parts with a few high-strength reinforcements and commercial, off-the-shelf avionics.  To reduce drag and simplify design, the team used a “Blended Wing Body” (BWB) design in which the main aircraft body and the outer wings blend seamlessly into each other. Its wings consist of just four component pieces each which fit together “out of the box”; In other words, according to Cohen and Inouye’s presentation, the craft can be easily assembled by “anyone who can build IKEA furniture.” 

Illustration of "blended wing" structure with launcher inset

3D Printing Expertise and Choices

To achieve an accurate outer mold line (OML) for the surface of the aircraft, Purdue/BYU printed its parts with the span aligned along a vertical axis. This allowed their printer to lay the outline of the wing (the airfoil) in one continuous motion and avoid the creation of problematic jagged edges.  Internal wing ribs were designed to lie within 45 degrees of the vertical, which allowed them to print without support material. Using less support material allowed the team to save production time, lower manufacturing costs, and reduce waste.

The pair pointed out that larger printers can generate structures built of fewer parts. Fewer parts require fewer interfacing subassemblies, greater structural integrity, and less overall weight. For aircraft manufacture, weight reduction is vital. 

To Cohen and Inouye, Additive technology had clearly not eliminated the need for production expertise; rather, it had demonstrated the importance of a whole new production expertise.

“I’ve got to toot Aaron’s horn a little bit here,” Cohen said, clearly pleased by Inouye’s contribution. “Through this project, he really became one of very few people in the world who deeply understands the intricacies of 3D printing really efficient high-performance structures.” 

He went on: “Anyone can draw up a block or a cube or sphere and print it out and say ‘Hey, I printed something.’ But to really understand how to utilize the machine and how it builds a part, what the strength of that part will be, how the parts will fit together is rare.  What Aaron did meant we only needed one model printed. There was no iteration -- no second draft. It arrived in a box and took effectively no time to assemble -- and it just flew.”