Desenho de experiências - estratégicas

O desenvolvimento de produtos e processos pressupõe a realização de experiências que conduzam à sua optimização ao menor custo possível. As estratégias a utilizar na condução das experiências, bem como o tratamento estatístico dos resultados alcançados, deverão conduzir às melhores condições de realização dos ensaios necessários à prossecução deste objectivo. O método de Taguchi permite obter informação relevante, com um número reduzido de experiências, conforme se demonstra nos casos de estudo apresentados

Metallurgical evaluation of laser sintered M3/2 HSS powder

Direct Metal Laser Sintering (DMLS) is one of the leading commercial rapid tooling (RT) technologies that produce 3D fully functional parts and tools directly from a CAD model. High Speed Steels (HSS) have the desired combination of hot hardness, wear resistance and toughness needed for applications such as cutting tools, special tools, inserts and dies that can be successfully developed in a near net shape by DMLS. This paper presents a study of DMLS of commercial water atomized M3/2 powder with different apparent densities. The effect of apparent density and DMLS process parameters on the surface morphologies and microstructure of laser sintered M3/2 powder was analysed and the optimum processing conditions to reduce balling effect were identified. Laser sintered M3/2 HSS with energy densities between 2.4 and 12 J/mm2 produced a coarse roughness (Rz) ranging from 135 to 234μm. The lowest roughness (65μm) was obtained with 36J/mm2, the highest laser energy density value used. The microstructure of laser sintered M3/2 HSS consisted of austenite, martensite and a fine carbide structure