Cladding formation in laser-beam fusion of metal powder

Current commercial rapid prototyping systems can be used for fabricating layered models for subsequent creation of fully-dense metal parts using investment casting. Due to increased demand for shortened product development cycles however, there exists a demand to rapidly fabricate functional fully-dense metal parts without hard tooling. A possible solution to this problem is direct layered rapid manufacturing of such parts, for example, via laser-beam fusion of the metal powder. The rapid manufacturing process discussed herein is based on this approach. It involves selective laser-beam scanning of a predeposited metal-powder layer, forming fully-dense claddings as the basic building block of individual layers. This paper specifically addresses only one of the fundamental issues of the rapid manufacturing process under investigation at the University of Toronto, namely the fabrication of single claddings. Our theoretical investigation of the influence of the process parameters on cladding's geometrical properties employed thermal modeling and computer process simulation. Numerous experiments, involving fabrication of single claddings, were also carried out with varying process parameters. Comparisons of the process simulations and experimental results showed good agreement in terms of overall trends.