Direct manufacturing of metal prototypes and prototype tools

Due to the limited mechanical characteristics of the materials which can currently be processed using industrially available Rapid Prototyping machines, a lot of research is focused on the development of techniques which allow for a direct manufacturing of metallic parts. These include Selective Laser Sintering and Controlled Metal Build Up Both methods produce the workpiece not by removal of material but by a layerwise deposition and local melting or sintering of a powder material without part-specific tooling. Controlled Metal Build Up is a new Rapid Prototyping technique similar to Fused Deposition Modeling combining laser generating/welding with conventional 2 1/2 dimensional milling. Due to the excellent surface quality and high dimensional and form accuracy achievable with Controlled Metal Build Up, this technology offers an interesting alternative to the conventional time consuming processes for the manufacture of prototype tools required for limited production runs. With respec t to Selective laser Sintering, a test facility was developed for experimental investigations into the direct sintering of low and high melting metallic powders without the use of a polymer binder as well as ceramic powders. Great potential is expected from Selective Laser Sintering concerning the prototyping of molds and dies. This paper will discuss current developments for these two techniques as well as point out possible applications and future developments.