Free Form Fabrication of Metallic Components Using Laser Engineered Net Shaping (Lens)

Griffith, M. L.
Keicher, D. M.
Atwood, C. L.
Romero, J. A.
Smugeresky, J. E.
Harwell, L. D.
Greene, D. L.
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Solid free form fabrication is one ofthe fastest growing automated manufacturing technologies that has significantly impacted the length oftime between initial concept and actual part fabrication1 2. Starting with CAD renditions of new components, several techniques such as stereolithography3 and selective laser sintering4 are being used to fabricate highly accurate complex three-dimensional concept models using polymeric materials. Coupled with investment casting techniques, sacrificial polymeric objects are used to minimize costs and time to fabricate tooling used to make complex metal castings5 • This paper will describe recent developments in a new technology, known as LENSTM (Laser Engineered Net Shaping)6 7 8 9, to fabricate metal components directly from CAD solid models and thus further reduce the lead times for metal part fabrication. In a manner analogous to stereolithography or selective sintering, the LENSTM process builds metal parts line by line and layer by layer. Metal particles are injected into a laser beam, where they are melted and deposited onto a substrate as a miniature weld pool. The trace ofthe laser beam on the substrate is driven by the definition ofCAD models until the desired net-shaped densified metal component is produced.