Inside 6K Additive's automated metal 3D printing powder production plant

The company's 40,000-square-foot facility nears completion.


6K Additve

Timing is everything.

The perfect time to announce your company to the market is weeks before one of the industry’s biggest trade fairs; the opportune moment to unveil your first available materials are at said event with thousands walking the show floor; but slating the completion of your state-of-the-art production facility for Q1 2020, it turns out, would be less than ideal.

While 6K Additive may have planned to follow up its additive manufacturing trade show debut at Formnext, with a presence at spring-time events on home soil in North America, waxing lyrical to attendees about its newly operational 40,000-square-foot facility, it wasn’t to be. As all hands ought to have been on deck adding the finishing touches towards the end of winter, the spread of COVID-19 meant staff were working around the clock on more dispersed shifts, with more self-performing tasks being carried out, deep cleans conducted at the end of each work schedule and the company having to be patient for external contractors to complete electrical and drainage work.

But now, the company is nearly there.

“It’s been a challenge,” 6K Additive President Frank Roberts tells TCT, “I’m not going to say it hasn’t, but I’m really proud of the work we’ve done. We never 100% idled progress on construction and installation. We had to get very creative but continued to make pace and I think, as a group, we collectively minimised the impact pretty successfully.”

The facility is based, and not by accident, on a 45-acre campus in Burgettstown, Pennsylvania, allowing plenty of scope to expand should the business require it. It is here where 6K Additive will produce metal powders for companies in a host of vertical markets, with high-quality, low contamination and increased safety of employees the ends, and an extensively automated, ‘nearly lights out’ facility the means. Inside, there are multiple of the company's UniMelt microwave plasma platforms turning scrap metal into additive manufacturing material, each with the capacity to produce 100 tonnes of powder per year. But rather than employees carrying out the manual tasks, it will be pieces of technology doing the heavy lifting in isolated process cells, while staff monitor proceedings from a control room equipped with cameras and Programmable Logic Controller (PLC) systems.

“Automation is a key component to how we produce product,” Roberts says. “There will be minimal operators and material handlers coming into contact with the product; so, it’s automated feed systems and a lot of PLC controlling the process throughout, whether it be the sizing of the feedstock through the UniMelt and spiritisation steps through post-sieving and blending. It’s very much hands-off.”

6K has deployed a mechatronic system to control its mechanical equipment, with factory staff putting material into position and standing back as the material is automatically loaded and unloaded and other mechanical systems clamp containers into the correct position. The material is moved around the facility on conveyor and dumper systems, while 6K employees assume their position in the control room to keep check of things like air quality. This all happens not only to limit contamination within the powder, and to protect the quality of parts subsequently manufactured with the powder, but also to keep those in the facility as safe as possible.

6K Additive

In this spirit, the facility has been sectioned into two parts focusing on reactive and non-reactive materials. On the reactive side where 6K Additive will first focus on the Onyx Ti64 material unveiled at Formnext, there are flame and smoke detection cameras installed to catch any unwanted chemical reactions early. The non-reactive side will get started on 6K’s Onyx In718 nickel-based alloy, also debuted in Frankfurt. Here, 6K has already begun making powder, tested all aspects of the system and intends to attribute its learnings to the more volatile and dangerous section of the facility, where 6K has so far only been ‘striking plasma and monitoring the control elements of the reactor’ ahead of ramping up production of its titanium powder later this summer.

As production steps up in the coming months, and with 6K looking to ensure that its powder supply is secure, the company has also designed into its facility a way of shielding each reactor from the other. In the event of an unwanted chemical reaction on the reactive side of the building, all staff should be protected, and the rest of the facility can keep running and keep producing as planned.

“We have this compartmentalised philosophy of processing, so each reactor has its own cell,” explains Roberts. “On the titanium side, the reactive side, each cell is equipped with deflagration vents and glass doors so that in the event of a release, or something goes catastrophically wrong, you’ve got a deflagration system designed into the building that sends it out away from where you have any people. It’s a very, very different way of processing this type of material versus what you see in maybe some conventional gas atomised plasma processes.”

As the facility nears completion this summer, and despite the many disruptions the pandemic caused, 6K Additive announced at the end of June the first commissions of its UniMelt plasma technology. The first two, which were announced on June 24, were unnamed in the company’s press release, though 6K Additive is working in some capacity with companies such as Midwest Composites, Keselowski Advanced Manufacturing and Castheon. Aerospace and defence companies are said to have expressed their interest and are in early discussions with 6K Additive, while medical implant manufacturers have enquired about the availability of the company’s titanium powders, and Relativity Space became the first named customer on June 30.

This partnership with Relativity will look to turn the rocket company’s scrap metals into additive manufacturing powder for the manufacture of its rocket components, while also exploring the development of new materials designed to directly meet Relativity’s needs. The collaboration will be based at 6K Additive’s site with the material being developed in Burgettstown and delivered to Relativity HQ in Los Angeles. Per 6K Additive’s business model, this will be the case for most commissions of its technology, though exceptions may be made for larger organisations who wish to integrate the 6K technology and action a complete cycle within their facilities. In these instances, however, 6K Additive personnel would still run the UniMelt system onsite.

The idea is to enable more companies to use additive manufacturing in a much broader way.

As with Relativity, 6K will also work with these companies to add new materials to the portfolio based on their requirements for printed applications. The availability of the nickel and titanium materials has been prioritised because they have been deemed most likely to be required in higher volumes, but what comes next is likely to be specialty powders. At Formnext, 6K Additive highlighted its ability to alloy five unique elements – in which two of them had melting temperatures some 900°C apart – into a feedstock that can be put through the UniMelt platform and turned into powder. This powder has not been produced to necessarily be used for any given application, but instead to evidence the company’s capacity to tackle materials that can’t be developed elsewhere. To this end, 6K is already making progress.

“We’re getting a lot of folks approaching us to create materials that can’t be produced anyplace else,” 6K Additive’s Chief Marketing Officer Bruce Bradshaw notes. “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].”

The material being developed with the medical firm is not far from being introduced to the market, with testing for this product, and other powders, being carried out through the summer. This process not only includes assessments inside the 6K Additive facility in Burgettstown but also includes external third-party testing in both the EU and the US to satisfy the aerospace customers. 6K Additive is also harnessing some of the lab and testing facilities from 6K’s conventional manufacturing business.

It is from the very top of those conventional manufacturing operations, in the form of 6K CEO Aaron Bent, where the additive manufacturing business came to be. Before a rebranding last year, 6K was known as Amastan and 6K Additive as AL Solutions; two separate entities that partnered three years ago in a development project and later came together as the result of an acquisition, bringing AL’s titanium handling and ‘circular economy’ capabilities under the control of Amastan.

6K Additive

This, the two parties agreed, was the best way to penetrate the additive manufacturing space. And they do so with the promise of high throughput production of high-quality, and often specialty, metal powders. These materials are said to be ‘truly spherical, void of porosity and with better flowability’ and are to be produced at nearly 100% yield thanks to a highly uniform, zero contamination plasma zone within the company’s UniMelt technology. 6K Additive is not only wanting to turn scrap metal into processable powders that are superior to other products on the market but in doing so, reduce significantly the amount of waste generated in the second cycle of these materials. 

“We’re achieving size before we ever turn it into spherical powder. That’s the key to our success,” explains Roberts, “making sure that we’re only putting in the reactor exactly what we want to size and what the customer is looking for. The other key component is, by doing that, because you have this perfect particle size distribution, and going into the reactor already sized, it’s injected into our column of plasma in a very controlled way. So, each discrete particle sees this nice column of plasma with not much chaos, like you would typically see in gas atomisation or plasma atomisation, and you end up with those discrete particles falling through the plasma, melting and solidifying very, very quickly. You don’t see the formation of the satellites; you don’t see any porosity because you don’t have the high-velocity gases impacting that molten stream. That’s what ultimately gives us a very high yield.”

The company hopes this will give them a USP in a market that is increasingly competitive and gradually delivering higher and higher volumes of parts. With a fleet of UniMelt systems set to be installed in the 6K Additive plant, all capable of producing 100 tonnes of powder a year and all supplemented by state-of-the-art automation technologies, the company is looking to help address those high volume demands across a range of industries. On a 45-acre site, the room is there to grow, and as 6K Additive assesses the current rate of additive application, it believes, with regards to the company's arrival, its timing has been impeccable.

“The intent, here, is to ultimately enable larger scales,” Roberts says. “One UniMelt is 100 tonnes a year of capacity, we currently have two reactors coming online with space for two more in 2021 – the way we’re set up, we’re designed to expand pretty easily. The building is very modular in a way that we continue to just add bays and add reactors. The idea is to enable more companies to use additive manufacturing in a much broader way.”

“I think the timing for us is spot on,” Bradshaw adds, “because companies are looking to go to volume production. It’s not there yet, as we know, but it’s moving in that direction. For us, because our business model allows companies to scale to production volumes that others won’t have the ability to do, entry to market is timely on that front.”

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