The challenge of producing high-quality additive manufacturing powders

Additive manufacturing may be transforming industries such as aerospace, automotive, healthcare and tooling; but a major challenge persists - how can companies produce additive powders of a robust and repeatable quality?

The Manufacturer’s Marc Hauschild caught up with Eddie Andrews, of Swiss-based technology pioneer Oerlikon, to learn how controlling the ‘additive value chain’ could hold the key.

Metal 3D printer (DMLS) Additive Manufacturing - image courtesy of Depositphotos.
How can companies produce additive powders of a robust and repeatable quality – image courtesy of Depositphotos.

Oerlikon provides a range of additive manufacturing processes technology and services, and has focused its key business areas on creating an end-to-end ‘additive value chain’.

The company has been producing metallic powder – through powder atomisation – for more than 60 years and has gained a significant amount of expertise in this area over that time.

Oerlikon is also known for its range of advanced coatings, such as thermal spray and laser cladding coatings which are typically used in critical high-heat aerospace applications.

More recently, it has become a world-leader in additive manufacturing – drawing on its knowledge of advanced materials, processes and technology.

Oerlikon’s unique position enables it to offer full turn-key solutions, from supplying the powder alloy and additive manufacturing processing, to heat treatment and surface engineering. This vertical integration of the entire ‘additive value chain’ means the business benefits from far greater control over quality, transparency and traceability.

Eddie Andrews, additive manufacturing business development manager at Oerlikon, explained to The Manufacturer: “We started [our transformation into an additive company] quite slowly four years ago with some R&D machines in North America.

“However, the companies first significant additive milestone was an investment in the German additive manufacturing company, Citim GmbH, in 2017. The company was centred around the automotive industry and it created an additive company in North America in Atlanta.”

Since its acquisition of Citim, Oerlikon has made further acquisitions, including Scoperta (a simulation rapid alloy development company based in San Diego) and DTI (an additive company that previously part of GE Medical).

Oerlikon has also invested in two new facilities:

  • An additive powder gas atomisation facility in Michigan with both Electrode Induction Melting Gas Atomisation (EIGA) and Vacuum Inert Gas Atomisation (VIGA), which is expected to produce up to 1,000 tonnes of ‘atomised’ powder each year. EIGA and VIFA allow Oerlikon to achieve the high-quality requirements associated with aaerospace for both reactive (titanium and aluminium) and non-reactive alloys (steel and Nickel). The facility will reportedly be operational by August 2018.
  • A 125,000 sqft  additive manufacturing facility capable of managing every process from receipt of powder to fully finished components. The facility will reportedly be supported by big data analytics to achieve the operational efficiencies required for production. At full production, the facility has the capacity to house between 100 and 120 machines with full post-processing, capable of handling 10 tonnes of metal powder every day.

Achieving robust and repeatable quality

When it comes to working with OEMs, the first challenge for an additive manufacturing firm is guaranteeing quality of supply.

Andrews noted: “We invest a lot in quality testing processes for every part that we manufacture to validate the quality in the components, however, this gives us quite a high scrap rate.”

Oerlikon is also known for its range of advanced coatings - image courtesy of Oerlikon.
Oerlikon is also known for its range of advanced coatings – image courtesy of Oerlikon.

The second issue, Andrews continued, is commercial viability. Factors such as high scrap rates and significant quality testing of each part means the process currently carries a high cost.

“We need to invest a lot of money in high quality, repeatable, robust process testing until we get to the point where we are confident that the quality of the material is good.  The fundamental challenge of additive industrialisation is that the prime engine and airframe OEM’s first need to invest in qualifying the additive process and technology.

“At the same time, the supply chain needs to invest in the facilities and capacity to support it. These two factors are dependent on each other and therefore risk-sharing partnerships between OEM’s and supply chains are required.”

Does data hold the key?

The data Oerlikon collects from its qualification programmes is sent to the FAA (Federal Aviation Administration) and the CAA (Civil Aviation Authority) to validate and sign off the processes.

Andrews explained: “Additive manufacturing qualification started more than 10 years ago with the OEM’s using ‘single part qualification’. Whereby, we validate the quality of the parts we build each time with destructive and non-destructive testing techniques. While robust, the increased validation is expensive, and it doesn’t really tackle the associated high scrap costs.”

Earlier this year, Oerlikon announced a five-year partnership with Boeing to co-create standard materials and processes for metal-based additive manufacturing.

Additively manufactured metal bracket for space applications - image courtesy of RUAG.
Additively manufactured metal bracket for space applications – image courtesy of RUAG.

The pair aim to use the data from this collaboration to support the qualification of additive manufacturing suppliers to produce metallic components using a variety of machines and materials; as well as review non-destructive testing methods and, where possible, validate quality through ‘live’ statistical data.

Andrews concluded: “Having our own powder atomisation, additive printing and heat treatment capability, we control all the data throughout the core process of creating a material.

“This helps to understand the key process variables and the stable operating window each key process variable needs to operate within to achieve repeatable quality.”

He continued: “The interesting bit for me is that we are embracing these processes with big data analytics. We are developing tools with the likes of Boeing, enabling us to communicate data to validate components without having to do traditional validations of destructive testing and non-destructive testing.

“This adds both efficiencies to the manufacturing process, while making the manufacturing more cost-effective. The data insights also give us more confidence. We only have to inspect something if there is an anomaly in the data which does not fit into the process window.”

The Manufacturer also spoke with Eddie Andrews about the company’s partnership with Lufthansa Technik and the collaboration between Oerlikon and RUAG Space.