Amorphology Inc., a NASA spinoff company founded from technology developed at the Jet Propulsion Laboratory (JPL) and the California Institute of Technology, has partnered with Additive Technologies (AddiTec), a founding partner of Meltio, an additive manufacturing company pioneering the development of affordable metal 3D printing systems. Together, Amorphology and AddiTec are developing the additive manufacturing of large steel strain wave gear flexsplines.
Strain wave gears are a compact and zero backlash gearbox used in robotic arms and precision-motion mechanisms. They transmit torque through a geared thin-walled cup, hat, or band, called a flexspline. The flexspline has precise gear teeth and a flexible wall, a combination of qualities that drives the manufacturing costs of a strain wave gearbox. Because of their complexity, strain wave gears can account for a substantial portion of the cost of a six-degree-of-freedom (6DOF) robotic arm.
“When you look at machining of flexsplines that are six to eight inches in diameter, the large steel feedstock may be reduced to as little as 10 percent of its original volume. This is a detriment from both cost and sustainability standpoints, as energy and material are wasted to produce a part which is a shell of the original stock. Additive manufacturing becomes a promising alternative since the machining costs can potentially be dramatically reduced while allowing for the cost-effective use of high-performance steels,” said Dr. Glenn Garrett, Amorphology CTO.
Amorphology and AddiTec together have demonstrated a 6-inch diameter prototype of a strain wave gear flexspline printed in high-performance 17-4 precipitation hardened steel. The prototype was fabricated on a Haas CNC hybrid system running the Meltio Engine. The printed part was removed from the build-tray and then CNC machined into the precision shape. The process also allows for flexible and on-time production of a variety of large flexsplines without having to keep many diameters of stock in house.
“AddiTec uses Meltio’s laser metal deposition with wire and/or powder (LMD-WP) technology (a form of DED). In LMD-WP process, lasers create a melt pool in which wire and/or powder is fed to create weld beads. These weld beads are then layered precisely to fabricate near-net shaped metal components. This technology can be used to create components from a CAD design or for part repair. In addition, the ability to integrate with a CNC machine makes it a hybrid system. Hybrid manufacturing is a ‘one-stop solution’ for seamless metal component production — it combines both additive and subtractive operations on one common platform, thereby reducing the overall cost and time for fabricating components,” said Brian Matthews, CEO of AddiTec.
Amorphology & AddiTec plan to develop this technology and expand their partnership to multi-material and functionally graded material flexsplines, which cannot be produced conventionally.
MORE INFO www.amorphology.com or www.additec.net
