Topology Optimization Key to Additive Manufacturing

Topology optimization, an industry term that Wikipedia defines as “A mathematical approach that optimizes material layout within a given design space,” could be a critical motivator to create industrial designs specifically for additive manufacturing.  In a captivating presentation at the Inside 3D Printing Conference in New York City, Jim Hassberger and Tony Norton from solidThinking explained how a technology inspired by bone structure research done over a century ago combined with the power of modern computing has led to a new way to optimize load-bearing structural designs.

The results of topology optimization are structures that have outward dimensions identical to normal load-bearing elements such as beams, yet have interior dimensions that look very different from traditionally manufactured parts.  In place of triangular or circular voids, these parts have remarkably organic, almost bone-like shapes.  The reason is, topology optimization software systematically analyzes the stresses on these shapes and then removes the most superfluous material from the design.  This process is repeated over and over by the optimization software, and by the end the computer design leaves only a skeletal interior structure.

Image from compumod.com.au

So what makes these specially designed parts so special?  Why design a part that is so complex?  The advantage of parts made with topology optimization is that the same strength characteristics can be created with less material, and this yields a greater strength to weight ratio, an important property across most industries related to transportation.  As a practical example, structural rib elements in an Airbus wing designed with topology optimization saved over 500kg in structural weight, which translates to significant cost savings.

The computing power to run topology optimization software became available in the 1990’s, but the technology did not spared as imagined by its creators.  Reflecting on its limited success twenty years ago today, Mr. Hassberger and Mr. Norton note that the real difficulty wasn’t in designing parts, but in producing them.  Three-dimensional designs created in such a way were often highly irregular with strange voids and curved interior surfaces, making them all but impossible to machine or cast using traditional manufacturing methods.  And that’s why they are so excited to reintroduce the technology today.  Additive manufacturing, a process in which “Complexity is free” according to 3D Systems CEO Avi Reichental, makes producing these highly complex forms as easy as producing straight, right-angled beams.

While there is still some cost associated with adopting topology optimization, not least of which is a software license starting around $6000, a process that used to be “by PhDs for PhDs” and almost prohibitive to manufacture can now be incorporated into designs after only four hours of training and access to additive manufacturing.  And as apparent proof of its value, these designs are already being incorporated into biomedical, Formula 1, UAV and traditional aerospace assemblies.

So will topology optimization be the latest catch phrase at the next Maker Faire you attend?  Probably not.  However it does promise to demonstrate to industry that additive manufacturing can bring even greater design optimization to existing products, and that is good news for everyone who hopes to see even wider adoption of this paradigm-shifting technology.

Authored by Brian H. Jaffe, founder of Mission St. Manufacturing and contributor to On 3D Printing.

Cover images from solidThinking.com