Additive Manufacturing (AM) is not as sustainable as you might think. Click to our special feature from this very issue and you’ll find hot takes from myriad industry leaders on the intrinsic sustainability properties the technology can offer versus the areas where more consideration needs to be taken.
One of those voices is 6K Additive, a newcomer to the AM market who, despite its potential, claim AM to be no more efficient than subtractive manufacturing. In what it describes as “the dirty little secret of making powders for additive manufacturing”, whereby an estimated 70% of material is lost in the manufacture of powder and up to 40% lost in printing, 6K believes it has the ability to uniquely address this challenge and recapture that lost productivity value in a way that leverages certified scrap material from CNC millings and turnings that makes producing AM sustainable.
With a reported 1 million pounds of titanium powder capable of being upcycled per year at its dedicated ISO9001 facility, it would appear they may be onto something.
Designer material
For the longest time, post-processing has shouldered the guilt as AM’s “dirty little secret” but 6K, a company specialising in plasma technology with a dedicated focus on additive, says the onus belongs elsewhere.
According to research from The Barnes Global Advisors, powders are on track to become the single dominant cost of an AM part over the next five years. Using the example of a titanium component, as improvements in print technology and process improve, total part cost is expected to decrease dramatically by around 70%. As a result, by 2025 powders will foot the majority of the bill of an additive part at around 40% of the total cost.
But one person’s scrap is another person’s gold. Citing an inherent link between sustainability and cost, 6K, whose technology converts certified chemistry machined millings, turnings and other recycled feedstock sources into premium AM-ready metal powders, believes it has the solution, located inside a new 45-acre campus in Burgettstown, Pennsylvania.
Spinal implants 3D printed from reclaimed Ti-64.
Enter 6K’s UniMelt Plasma System, a first of its kind plasma-based system for advanced nanomaterials production, which aims to eliminate the waste that exists in today’s material production process by fine tuning powder to the needs of the 3D printer. Essentially, any machined alloy can now become a 3D printable powder.
Compared to plasma and gas atomisation techniques traditionally employed to manufacture AM powders, feedstocks processed via the UniMelt system are said to deliver up to four times the amount of usable powder for strong, high-density parts made by laser, EBM and binder jet processes. Feedstock is processed in a contamination-free inert atmosphere to create perfectly spherical, porosity free, high flowing powder in a single-pass continuous process which turns commodity feedstock into engineered particles in just two seconds with up to 100% yield. The resulting powder is said to provide “superior performance and versatility versus best-of-breed powders.” Operating at 6,000 degrees, the UniMelt process is capable of high throughput production of advanced materials including Onyx Ni718 and Onyx Ti64 AM powders and a wide range of ferrous alloys, nickel superalloys, cobalt-based alloys, refractory metals and beyond.
Impossible alloys
Back in June, 6K announced commissions of its first two commercial systems for the production of nickel super alloys and titanium powders, with plans to commission additional UniMelt systems throughout 2021. While nickel and titanium have been prioritised due to expected demand, for what comes next, 6K believes it’s important to look at where the value is. Sure, they could do stainless steel and aluminium if they wanted to, but 6K says it’s more interested in producing what others can’t.
“We have the ability to produce materials that you can't produce conventionally and haven't been produced additively,” 6K Additive’s Chief Marketing Officer Bruce Bradshaw explained, pointing to an example showcased at last year’s Formnext. This world-first High Entropy Alloy “Unobtanium” 3D printed part saw 6K alloy five unique elements, including two with melting temperatures ~900°C apart.
First ever High Entropy Alloy “Unobtanium” 3D printed part.
For industries like medical, automotive, and aerospace, these new material possibilities are thought to be opening up opportunities for products that were not otherwise achievable through conventional melt approaches. Whether it’s an oil & gas engine impeller printed using reclaimed Ni625 or rejuvenating powder for rocket propulsion as demonstrated in a recent partnership between Relativity Space, 6K’s UniMelt’s new process for producing premium powder in a sustainable way is setting a new mark in advanced materials.
“We’re getting a lot of folks approaching us to create materials that can’t be produced anyplace else,” Bradshaw said. “The aerospace market is looking for alloys that have unique characteristics; high temperature, different melting points, things along those lines for rocket engines [for example]. On the medical side, we’re working on a material that you commonly see as a coating, but it’s not produced as a full implant. This [material] has legs across the entire medical space, it won’t just be limited to one company, but this initial company will come out to market with their first product [using this material].”
Providing the example of the orthopaedics market, 6K says it can produce TiN powders for a revolutionary approach to 3D printed femoral components which could lead to a single material implant that’s half the weight of a typical industry standard design and 50% reduction in patient wait times.
As AM factories become a reality, 6K says it can also create long-term, value-based relationships through a circular supply chain. That means any waste generated by users through the likes of used powder, support structures or non-spec parts can be fed back into the UniMelt system to create new, virgin powder and unlock further value.
Additive manufacturing has the lead in terms of sustainability over conventional manufacturing, but clearly, as 6K has demonstrated, there are vast improvements on the materials production front that take AM to a whole new level of environmental impact and ultimately, enable additive to live up to its true sustainable potential.
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