Research Assistant Professor The Roux Institute at Northeastern Unviersity
Powder based additive manufacturing (AM) depends on feedstocks with tightly controlled particle size and high sphericity, attributes typically achieved through gas, plasma, or ultrasonic atomization. In contrast, mechanical recycling via comminution offers a solid-state pathway to transform metal scrap into AM ready powders. This perspective examines the role of comminution in recycling metals into AM feedstocks. We review established mechanical methods for breaking down metal into powders and highlight the resulting differences in particle size and morphology compared with atomized materials. The implications of these irregularly shaped feedstocks are discussed across different AM process types, including their effects on powder spreading (e.g. powder bed fusion) and deposition efficiency (e.g. cold spray). We then present a lab based demonstration using multi-stage planetary ball milling to convert metal swarf into feedstocks with AM suitable size and morphology. As proof of concept, the recycled powders are successfully deposited using cold spray. Our analysis includes characterization of the evolution of particle size, shape, crystallinity, and chemistry through successive milling stages. We conclude by discussing the advantages and challenges of mechanical recycling relative to atomization and highlighting opportunities for integrating comminution based methods into sustainable powder production workflows.
Learning Objectives:
Upon completion participants will understand what characteristics of powder feedstocks are important and recognize how how feedstock size distribution and shape can affect build quality.
Upon completion participants will recognize what hardware is available for mechanically breaking down metal scrap to additive feedstocks.
Upon completion, participants will understand the pros and cons of using mechanical comminution for making metal powders.
