May 2, 2022

Amorphology400x275Amorphology, a NASA spinoff company created from technology developed at the Jet Propulsion Laboratory (JPL) and the California Institute of Technology, has announced a partnership with Additive Technologies (AddiTech), which develops affordable multi-metal 3D printing systems. Together, the two companies are developing the additive manufacturing of multi-metal gear components for robotics.

Building on their previous collaboration of 3D printing large-scale strain wave gear flexsplines using directed energy deposition (DED), the partnership will now focus on developing multi-metal, functionally graded gear components that combine two different steels together within a single part. The three-inch diameter flexspline demonstrator is part of a zero backlash strain wave gearbox used in robotic arms and precision-motion mechanisms. 

“The thin-walled flexspline has competing requirements of wear resistance in the teeth and a fatigue-resistant body that motivates the use of two different materials during 3D printing,” the companies said. “The steel in the toothed region is a precipitation hardening martensitic stainless steel typically used in high-strength applications with an average hardness of 35 Rc. In contrast, the steel below the toothed region is known for high toughness with a lower average hardness. By combining the two steels strategically in a gear, it becomes possible to tailor the mechanical properties to take advantage of the benefits of each alloy.”

Amorphology said it is developing its intellectual property around multi-metal 3D printing, specifically functionally graded metals, which allows for the strategic transition between more than one medal during 3D printing to produce multi-functional parts that are free from cracks and unwanted phases. Developed more than 10 years ago at JPL, the core technology focuses on the design of multi-metal transitions to achieve predictable mechanical or physical properties in the printed part.

“Functional grading with multiple materials allows us to develop gear components for robotics that cannot be fabricated with conventional metallurgy,” said Glenn Garrett, chief technology officer at Amorphology. “The ability to tailor the properties of a gear via alloy composition gives us an entirely new design freedom when developing precision mechanisms. Whether it’s improving the wear resistance of gear teeth while maintaining toughness in the rest of the part, or using high-value steel in combination with low-cost steel to save cost, multi-material additive manufacturing is allowing us to innovate in the way that we approach gears for robotics. We can tailor properties for machinability, cost, hardness, strength, corrosion resistance, even density. For large gears where it makes sense to use additive manufacturing to save machining costs, this could be a real advantage.”

The two companies said future work will focus on different combinations of steels, and the development of localized heat-treating strategies to optimize the properties of each metal in the bi-metallic gear. Amorphology said it is actively developing other applications for functionally graded metals in applications such as thrusters, rockets, robotics, and gears, and is seeking partners for further development and licensing.

For more details on the technology, visit the Amorphology website here.

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