When Failure Is Not an Option
Credit “Star Trek” with solving a legitimate lunar problem for NASA’s Artemis program: the 238,900-mile supply chain back to Earth. In the “Star Trek” universe, a “replicator” is a matter-energy conversion machine that produces food, tools, ship components, and more. As long as a molecular file is in the database, the replicator can spit it out, which is not too different than loading a CAD file into a 3D printer.
The engineers at NASA’s Langley Research Center in Hampton, Va. recognized the value of the “replicator” solution two decades ago. With the imagination of people such as Karen Taminger, a senior materials research engineer and technical lead for metal additive manufacturing (AM) at Langley (Read Story), they developed Electron Beam Freeform Fabrication, or EBF3, a metal 3D printing process that uses an electron beam gun, a wire-feed system borrowed from welding technology, and computer controls.
The EBF3 process can be used to manufacture metallic structures for building parts or tools in hours, rather than days or weeks. Unlike direct metal laser sintering (DMLS), the continuously fed wire process does not require gravity to work. Even in a vacuum, capillary action enables precise placement of molten metal. EBF3 also enables printing large scale items – think top of rocket fuel tanks big. The process uses standard metal inert gas (MIG) welding wire, which is available in aluminum, titanium, stainless steel, NiCrMO3 (e.g., Inconel 625), and other high-strength, light-weight aerospace alloys.
Instead of shipping and stocking thousands of spare parts, EBF3 technology could enable a lunar base or orbiting space station to use an onsite automated 3D printer. Stocking perhaps a dozen different alloys could cover the majority of needs when the next generation of astronauts needs a left-handed torque wrench or a new truss segment for the port side photovoltaic array panels.
COSM Advanced Manufacturing Systems is working with Langley via a Small Business Innovation Research (SBIR) contract (see COSM press release) to move the technology forward and address one of the fundamental challenges with AM – verifying component quality.
“COSM’s experience enables integrated visualization and sensing in real time to control and inspect work being performed in remote areas,” says Taminger. “The ideal situation is that you have the electron beam, the wire and the substrate all converging at the same point in space,” she says. “The challenge is that the size and placement of the molten metal deposit naturally fluctuates. With our EBF3 system at Langley, our operator was part of the control loop, manually adjusting key variables. COSM’s automated electron beam wire-metal 3D printing technology will bring closed loop control, as well as build machine intelligence into the system.”
While electron beam gun might also sound like something out of “Star Trek,” electron beam welding was invented in 1949. The process works by creating a vacuum and uses electric and magnetic fields to accelerate a narrow beam of free electrons so that they convey large amount of kinetic energy. On the extreme opposite end of power scale, a scanning electron microscope (SEM, invented in 1937) uses very low power. When the electrons strike a surface, they produce secondary and backscattered electrons, which creates a high-resolution image.
Richard Comunale, president and CEO of COSM, says that COSM’s system finds a sweet spot between the high beam power required for 3D printing and the finely focused beam required for imaging (view video on Ebeams: History and Power).
“COSM’s patented process is unique because it uses an electron beam to simultaneously melt the wire and provide real-time control over the process. We can make quality parts the first time and provide the data that prove it,” says Comunale. “Technically, our system delivers direct, continuous monitoring and dynamic feedback control of the 3D printing process based on electron beam image analysis for predictive anomaly detection and thermal management” (view video on Data Collection and Forensics).
COSM’s first generation commercial system, with anticipated delivery to NASA in December 2022, will have at least a 10 Hz refresh rate for user-defined corrective actions, which is comparable to decision making speeds used by autonomous vehicles. It will have a “write volume” of 1m3.
With never-before possible in-situ control over quality and material properties, as well as the ability to address supply chain challenges for critical components, COSM hopes its electron beam wire-metal 3D printing technology will capture a slice of the $16 billion market for large-scale metal AM parts (view video on Market and System Sizes). Potential applications include jet and rocket engines, air frames, aircraft repair, tool and die, petrochemical, energy, automotive, military, and anywhere users place a high priority on quality or need a reliable supply chain in remote locations.
Learn more about additive manufacturing (AM), attend the webinar Starting a 3D Printing Company, on Thursday, Sept. 9, at 10 a.m. ET and get to know the 3D printing companies exhibiting in the AM Pavilion at IMTS 2022.
About the Author
Benjamin Moses is Director of Manufacturing Technology at AMT-The Association For Manufacturing Technology. He worked in design and manufacturing world for aerospace components for 16 years, developing new products and implementing new and lean processes for legacy products. Benjamin now works with AMT’s Manufacturing Technology team to gather information about the latest technology research, concepts, and trends. This includes academic research and adoption of new technologies in manufacturing facilities. Through strong relationships with AMT’s membership, universities, and other industrial partners, AMT is able to gather a broad view on the state of manufacturing technology.