The Additive Manufacturer Green Trade Association (AMGTA) has released a report outlining the passivation requirements for metal powder bed melting condensate waste for transportation and recycling.

Developed by AMGTA members Sintavie and KBM Advanced Materials, the new process mixes the powder condensate with a removable resin to make the waste non-hazardous and shippable to a recycling plant. The removable resin is supplied by KBM.

Metal condensate – the term used for the excess soot and powder that is expelled from a build plate during the powder bed fusion 3D printing process – is considered a hazardous material and is therefore costly to eliminate. Currently, Sintavia passivates its condensate waste by mixing it with silicon oil and sand, which makes transport possible without the risk of flammability, but the metal powder cannot be recovered economically. Through its collaboration with KBM, Sintavia is testing alternatives to passivate the powder condensate and enable the reuse and/or recycling of the metal powder.

During testing of the condensate passivation process using KBM resin, the powdered condensate was mixed with the resin using a plastic spoon to form a paste, before being left to dry on a wooden tray. foil with parchment paper to prevent sticking. Using EOS RFS 1.0 H282 and EOS RFS 2.0 IN718, the following three scenarios were evaluated:

250g RFS 1.0 H282 + 5g KBM resin + 80ml solvent

1kg RFS 1.0 H282 + 15g of KBM resin + 150ml of solvent

237g RFS 2.0 IN718 + 5g resin + 40ml solvent

While all scenarios formed a dense paste that dried after a few hours, scenarios #1 and #2 were not completely solid and became crumbly after applying light pressure, while scenario #3 was completely solid. No hazardous situations were reported and air quality remained within acceptable limits. Sintavia and KBM are about to carry out additional trials with different types of powder condensate, but have gained confidence from initial trials that the procedure works.

“Today’s report is essential reading for any company involved in laser powder bed fusion metal additive manufacturing,” commented Sherri Monroe, Executive Director of AMGTA. “Not only does this new process reduce transportation costs, it is also reversible, meaning metal recyclers can have unsullied access to the underlying powder once it is received – allowing the potential to recycle waste that previously had to be put in a hazardous waste landfill.

“I hope other companies will adopt this new process as it will reduce their transportation costs since the underlying material is no longer hazardous,” added Brian Neff, Chairman of AMGTA and CEO of Sintavia. “This report is a great example of AMGTA’s leadership role in developing sustainable use practices for additive manufacturing.”

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