Recent Progress on 3D Printing of Lightweight Metal Thin-Walled Structures.

Metal thin-walled structures are ubiquitous in various industrial applications and fabricating them through additive manufacturing (AM) enables intricate thin-wall geometries with no assembly required. However, additively manufactured metal thin walls suffer from increased heat accumulation and reduced structural stability, making it difficult to print geometrically accurate thin walls with minimal distortion and defects. Thin-walled structures also experience different thermal histories and solidification conditions compared to bulk structures, leading to drastic differences in the microstructure and mechanical properties. In this review article, the AM processing of metal thin-walled structures will be introduced. An in-depth discussion on the design strategies of additively manufactured metal thin walls will be presented regarding the restrictions imposed by the AM technology, the integration of thin walls in lightweight structures, and novel design ideation through topology optimization. The effects that the thin wall design has on the geometrical accuracy, microstructure, and mechanical properties will then be elucidated. The utilization of AM for fabricating metal thin walls across various industries will also be summarized. Finally, this review article will close on some perspectives and future work on the AM of metal thin-walled structures.