Cladding formation in laser-beam fusion of metal powder

grantor: University of TorontoOver the past decade, many novel layered-manufacturing techniques have been used successfully for building complex 3D parts. However, parts built by these Rapid Prototyping (RP) methods have been used either for checking fit and geometry, or as models for subsequent creation of fully-densed metal parts using investment casting. Due to increased market competition and, in turn, shortened product development cycles, there is a demand to rapidly create the functional fully-densed metal parts without hard tooling. A possible solution to this problem is layered Rapid Manufacturing (RM), for example, via laser-beam fusion of metal powder. The RM process proposed in this thesis is based on this approach. It involves selective laser-beam scanning of a predeposited metal-powder layer. The laser beam melts the powder locally, forming fully-densed claddings, as the basic building block of individual layers. This thesis specifically addresses only one of the fundamental issues of the proposed RM process, namely the fabrication of single claddings. The most important process parameter, in this context, is the laser-beam scanning speed. The influence of this process parameter on cladding's descriptive parameters was investigated for two possible laser-working modes: pulsed and continuous. (Abstract shortened by UMI.)M.A.Sc