Additive manufacturing, or 3D printing, is still in its infancy when it comes to understanding the impact of subtle differences in manufacturing methods on the properties and capabilities of resulting materials. The Defense Advanced Research Projects Agency’s (DARPA’s) Open Manufacturing program seeks to solve this through efforts exploring three different materials and technological advances, such as in the fabrication of orthotic devices.
“The Open Manufacturing program is fundamentally about capturing and understanding the physics and process parameters of additive and other novel production concepts, so we can rapidly predict with high confidence how the finished part will perform,” said Mick Maher, program manager in DARPA’s Defense Sciences Office. “The reliability and run-to-run variability of new manufacturing techniques are always uncertain at first, and as a result we qualify these materials and processes using a blunt and repetitive ‘test and retest’ approach that is inevitably expensive and time-consuming, ultimately undermining incentives for innovation.”
The challenge with additively manufactured parts is that they are typically composed of countless micron-scale weld beads piled on top of each other. Even when well-known and trusted alloys are used, the additive process produces a material with a much different “microstructure,” endowing the manufactured part with different properties and behaviors than would be expected if the same part were made by conventional manufacturing. Moreover, parts made on different machines may be dissimilar enough from each other that current statistical qualification methods won’t work. Accordingly, each “new” material must be precisely understood-and the new process controlled-to ensure the required degree of confidence in the manufactured product.
To achieve this enhanced manufacturing control, Open Manufacturing is investigating rapid qualification technologies that could be applied not just to additive manufacturing, but to any of a range of potentially new manufacturing methodologies. The program comprises three efforts-two focusing on metal additive processes and one on bonded composite structures.
One concept being advanced is demonstrating a framework for affordable, rapid manufacturing of customized orthoses, such as leg supports for injured veterans, in quantities of one. This effort would transform the current approach for making customized orthoses-where each device is custom-crafted by a specialist-to an automated process allowing greater patient access, rapid device modifications, and improved durability, according to the DARPA press release.
“Historically, U.S. military advantages were supplied by breakthroughs in materials and manufacturing,” Maher said. “More recently, the risks that come along with new manufacturing have caused a lack of confidence that has stifled adoption. Through the Open Manufacturing program, DARPA is empowering the advanced manufacturing community by providing the knowledge, control, and confidence to use new technology.”
