Over the past decade, many novel layered-rnanufacturing techniques have ken used successfully for building compiex 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 fùllydensed metd parts using investment casting. Due to increased market cornpetition and, in tum, 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 pmblem is layered Rapid Manufacturing (RM), for example, via laser-bearn 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 rnelts 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.

The theoretical investigation of the process-parameter influence on cladding's geometricd properties employed computer modeling and process simulation. The commercial finite-difference, thermal-modeling software 1-DEAS TMG was used for the determination of the global temperature fields within the powder layer and the metal substrate due to the application of a laser-beam heat source. The cladding's expected geometry was reconstnicted using an algorithm based on surface analyticai geometry. The relationships between cladding's geornetrical properties, namely its width and height, and the scanning speed were detennined for both laser-working modes.

In order to verify the findings of the process simulations, numerous experiments, involving fabrication of single claddings, were carried out with varying process parameters. A generic experimental set-up, which can be used for both laser-working modes, was designed built and utilized for this purpose. Comparisons of the process simulations and experimental results showed good agreement in terms of overall trends.