Mass Finishing of Parts Produced by Direct Metal Laser Sintering

This paper presents some practical considerations on finishing of parts made by direct metal laser sintering (DMLS). The main process capabilities limitations of this promising rapid tooling technique are in fact in the surface roughness of the produced parts. This fact hinders the introduction of DMLS as a widely employed industrial process, especially for what concerns the production of moulds and inserts and allows their use only as preseries tools in injection moulding of plastics, since the requirements for preseries tools are worse than those needed during the process. Barrel finishing, in turn, is a well established technique to improve the roughness of parts of complicated shape by means of a soft mechanical action over the surface. The results herewith presented show that it is possible to achieve roughness of the order of 1 μm R_a even when starting from initial roughness of the order of 15 μm R_a, i.e. those typically attained by DMLS.