Recycled aluminium feedstock in metal additive manufacturing: A state of the art review.

Additive manufacturing has revolutionised the production of functional components and assemblies, offering a high degree of manufacturing flexibility. This review explores the latest advancements in additive manufacturing, focusing on its fusion-based and solid-state based technologies, and highlights the use of recycled aluminium as feedstock in these processes. The advantages and limitations of incorporating recycled materials are thoroughly analysed, considering factors such as material properties, sustainability, and process acceptance. While up to 14.4 kg CO2 per kg of aluminium is released during primary aluminium ingot production, solid-state based additive manufacturing, which is tolerant of feedstock contamination, can directly recycle aluminium. Meanwhile, fusion based additive manufacturing can readily utilise recycling pathways such as maintaining grade, upcycling, and downcycling, as well as powder reuse, providing opportunities for significant emissions reduction. The examination of feedstock manufacturing in this review, such as wire for WAAM and powder for PBF, indicates that this step indirectly increases the resource consumption of additive manufacturing. Finally, the alignment of aluminium recycling and additive manufacturing with Circular Economy principles and the UN's sustainable development goals are addressed, highlighting contributions to SDGs 3, 9, and 12.

Recording digital color information on transparent polyethylene films by thermal treatment.

This study characterizes the use of transparent low-density polyethylene laminate films for the purpose of recording digital information in the form of linear and color two-dimensional matrix codes that are distinguishable in polarized light. Color characteristics of multilayer laminated materials made from polyethylene and heat treatment methods for changing their coloring are examined. The contribution of the number of multilayer film interfaces to the lightness and color of the laminate is shown. Melt-extruded industrial polyethylene film heat treatment methods by convection, conduction, and radiation, to control their optical characteristics and color in polarized light, are studied.