Directed light fabrication of a solid metal hemisphere using 5-axis powder deposition

Directed light fabrication (DLF) is a direct metal deposition process that fuses metal powders, delivered by gas into the focal zone of a high-powered laser beam, to form a fully-dense metal deposit. Computer-based design and numerical controls are used in conjunction with the metal deposition process to guide the formation of 3D parts. This study demonstrates the ability to directly fabricate complex shapes using a 5-axis DLF machine. As an example, the production of a hemispherical shape is described, with the associated fabrication case study, metallographic examination and part characterization. The deposition of fully-dense stainless-steel components is achieved in all orientations, from horizontal to vertical, and dimensional comparisons between the DLF-deposited shape and the original part definition, illustrates that near-net shape tolerance levels are attainable within a 0.1 mm envelope. The single-step production of fully-dense, near-net shaped, 3D metal parts directly from a computer model is achieved without the use of forming dies, tooling or machining. As a result, significant process flexibility over conventional processing capabilities are recognized, with potentially lower productions costs and higher quality components. (C) 1998 Published by Elsevier Science S.A.