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 hi gh-powered laser beam, to form a fully-dense metal deposit. Computer-b ased design and numerical controls are used in conjunction with the me tal 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 s hape is described, with the associated fabrication case study, metallo graphic examination and part characterization. The deposition of fully -dense stainless-steel components is achieved in all orientations, fro m horizontal to vertical, and dimensional comparisons between the DLF- deposited shape and the original part definition, illustrates that nea r-net shape tolerance levels are attainable within a 0.1 mm envelope. The single-step production of fully-dense, near-net shaped, 3D metal p arts directly from a computer model is achieved without the use of for ming dies, tooling or machining. As a result, significant process flex ibility over conventional processing capabilities are recognized, with potentially lower productions costs and higher quality components. (C ) 1998 Published by Elsevier Science S.A.