## 3 Feedstock
### Powder Production
This technique is primarily utilized in specialized industrial applications, particularly for lower-melting-point alloys, where concerns such as erosion of the spinning disk or cup are less pronounced. Centrifugal atomization is characterized by lower energy consumption, primarily due to its reduced reliance on energy-intensive inert gases, making it a more energy-efficient alternative [48; 49; 50]. In order to offer potential solutions to the environmental and economic limitations of traditional approaches, alternative techniques to produce metal powder for additive applications have been specifically developed. These innovative methods, though less commonly utilized, have been developed with a focus on minimizing energy consumption, reducing material waste, and optimizing overall resource efficiency, making them promising candidates for addressing the environmental and economic challenges associated with traditional approaches. The Cold Mechanically Derived (CMD) process has been developed as an energy-efficient, solid-state approach that enables local, on-demand production of AM feedstock. Metal Powder Works' DirectPowderTM process offers a sustainable alternative to traditional metal powder production by employing mechanical forces to convert feedstock into fine powder particles without the need for high-temperature atomization. This low-energy approach incorporates methods such as crushing, milling, and grinding, enabling efficient conversion of raw materials to powder with a 95% yield rate while conserving energy. By eliminating the energy-intensive melting stage, CMD can reduce CO\({}_{2}\) emissions by up to 90% compared to conventional atomization processes [51]. CMD powders are typically irregular and non-spherical in shape, which may affect flowability and packing density in specific AM applications. However, in a study by [PERSON] et al. [44], CMD powder was evaluated against conventional GA powder for Al7075 alloy. The results indicated that CMD powder is capable of achieving material properties comparable to those of wrought materials. Despite its non-spherical morphology, CMD powder demonstrated effective performance in PBF-LB/M applications, establishing it as a viable alternative to GA powder. Key benefits include reduced energy consumption and improved material availability, highlighting its potential for sustainable manufacturing solutions. Another effective approach to enhance the sustainability of powder production is spheroidization, a cutting-edge technique that outperforms traditional methods. Plasma spheroidization technology produces highly spherical particles with greater efficiency, improved performance, and reduced impurities, making it an ideal choice for modern manufacturing. In this process, high temperatures generated by plasma melt powder particles, causing surface tension to reshape them into spherical forms as they descend through the reactor chamber. This method is versatile, capable of spheroidizing a wide array of materials, and is particularly well-suited for diverse industrial applications [52]. The UniMelt(r) process developed by 6 K exemplifies this advanced spheroidization technology. Utilizing microwave-based plasma, it eliminates the need for high-velocity gases, significantly reducing the risk of gas entrapment and ensuring the production of highly dense, spherical particles. UniMelt(r) provides precise control over particle size distribution (PSD), resulting in yields close to 100% within the desired PSD range. Tailored for AM processes such as powder bed fusion, this technique optimizes powder flowability and density, thereby enhancing overall performance. In addition to its technical benefits, the UniMelt(r) process is highly sustainable. It converts feedstocks such as used powders, swarf, and scrap metal into high-value metal products. By offering competitive rates for clean scrap metal, it promotes recycling and supports the economic viability of sustainable manufacturing.