Using ultrasonic atomization to recycle aluminium bronze chips for additive laser directed energy deposition

Using ultrasonic atomization to recycle aluminium bronze chips for additive laser directed energy deposition

Description & AMAZEMET association

In the maritime industry, large-scale manufacturing processes, such as ship propeller production, generate significant waste in the form of milling and grinding chips. A novel recycling approach using AMAZEMET’s rePowder ultrasonic atomization system transforms this waste into high-quality aluminum bronze powder suitable for Laser Powder Directed Energy Deposition (LP-DED). The process, conducted in an inert Argon atmosphere, ensures exceptional sphericity and a balanced particle size distribution, enabling superior powder flow and material consistency.This sustainable process chain not only reduces waste but also produces additively manufactured specimens with higher strength, competitive densities, and enhanced hardness compared to conventional cast materials. By turning post-processing waste into valuable feedstock, this approach exemplifies a circular economy in maritime manufacturing, paving the way for greener, high-performance production methods.

Authors

Vinzenz Müller ^a, Janek Maria Fasselt ^a, Tobias Kruse ^b, Christian Klötzer ^b, Rafael Kleba-Ehrhardt ^c, Tomasz Choma ^d, Max Biegler ^a, Michael Rethmeier ^{e a f}

a Fraunhofer Institute for Production Systems and Design Technology IPK, Pascalstraße 8-9, 10587 Berlin, Germany
b Mecklenburger Metallguss GmbH, Teterower Str. 1, 17192 Waren, Germany
c Technische Universität Berlin, Institute of Material Science and Technology, Chair of Advanced Ceramic Materials, Straße des 17. Juni 135, 10623 Berlin, Germany
d Division of Construction and Functional Materials, Warsaw University of Technology, Krakowskie Przedmiéscie 26/28, 00-927 Warszawa, Poland
e Institute for Machine Tools and Factory Management, Technische Universität Berlin, Pascalstraße 8-9, 10587 Berlin, Germany
f Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany

Abstract

In the post-processing of large maritime components, a considerable amount of waste in the form of milling and grinding chips is produced. At the same time, additive manufacturing technologies have shown great potential in producing high-volume parts for maritime applications, allowing novel design approaches and short lead times. In this context, this study presents a sustainable approach to recycle and use aluminium bronze waste material, generated during post-processing of large cast ship propellers, as feedstock for laser-powder directed energy deposition. The recycling technology used to produce powder batches is inductive re-melting in combination with ultrasonic atomization. The derived metal powders are characterized using digital image analysis, powder flowability tests, scanning electron microscopy as well as energy dispersive X-ray spectroscopy. Compared to conventional metal powders produced by gas atomization, the recycled material shows excellent sphericity and a powder size distribution with a higher content of finer and coarser particles. Metallographic sections of deposited additively produced specimens show an increased hardness and reduced ductility, but also competitive densities and higher yield and ultimate tensile strength compared to cast material. The process chain shows high potential for the maritime sector to enable circular and sustainable manufacturing.