Has a new producer of powders for additive manufacturing (AM) done the improbable, not just once but twice?
6K, formerly Amastan Technologies, North Andover, Mass., said its UniMelt microwave-based plasma technology can take metallic, alloyed and ceramic industrial scrap and turn it into premium powders for AM and other uses. Not only that, the company said it can make an infinite number of alloy powders for 3D printing.
“We can take specific ratios of different metal elements with vastly different melting temperatures, put them together to create a powder, and then print that powder, allowing companies to essentially design an alloy for their application,” said Aaron Bent, CEO of 6K.
To prove the point, 6K made a demonstration high-entropy alloy, Onyx HEA1000, a combination of iron and nearly identical ratios of chromium, cobalt, copper and nickel, and showed off a part made from it at a recent trade show.
The part was printed via laser powder bed fusion by Castheon Inc., Thousand Oaks, Calif., an AM R&D and service company.
The company’s first commercialized AM powder, Onyx In718, is expected this quarter. In late 2019, 6K and aerospace manufacturers were already working on getting the Onyx In718 powder qualified for use in production applications. A second powder, Ti64, is scheduled to hit the market in the third quarter of 2020.
In addition to its HEA part, the company demonstrated more than a dozen ceramic and metal powders and parts made from them at the show. 6K’s powder can also be used for more traditional manufacturing processes, such as metal injection molding and hot isostatic pressing. It also develops materials for silicon wafers, LED lighting, lithium-ion batteries and thermal coatings.
The UniMelt system uses materials that otherwise would be discarded from subtractive manufacturing, such as fines, turnings, and swarf, as well as supports, rejected parts and used feedstock from AM. The company uses these materials to create powders with high sphericity, zero porosity, no satellites, and high flowability and tap density, said Bent.
Not only is UniMelt capable of recycling what would otherwise be waste, it turns 100 percent of raw materials into usable powder, said Bent.
“Additive manufacturing is generally thought of as a clean technology, a sustainable technology, and in many ways it is,” Bent said. “But powder production is one of the industry’s dirty little secrets because of how inefficient and how wasteful it is.”
The yield resulting from gas atomization, one way metal powders are made, is only about 25 percent usable because of variances in the size of the powder spheres produced, he said.
“If you think about the energy and the cost of making an ingot, shipping it to a powder producer, melting it in a gas atomization system, making powder and throwing 75 percent of it away, it’s a massively inefficient process,” he said.
The company wants to contribute to a fully circular economy where 100 percent of the materials that enter the AM supply chain are used, and where manufacturers insist their parts be made from sustainable powders.