Selective laser melting for manufacturing of thin-walled porous elements

Selective laser melting (SLM) as additive manufacturing technology is studied in this paper for the generation of thin-walled elements with defined porosity characteristics. Building accuracy is studied and optimised regarding the manufacturing of thin walls. Leakage tests were performed to analyse the effect of wall thickness on gastightness. The influences of the SLM process parameters laser power, scan speed, and hatch distance on porosity and mechanical characteristics are investigated using a DoE approach. Porosity, permeability, pore size distribution, and tensile strength were analysed. Statistical significant regression models were found for porosity and tensile strength which allow tailored properties within the studied design space. A maximum porosity of 17.35% with a permeability of 2560 E-12 m2 was obtained. Macro pore sizes showed a unimodal pore size distribution with peaks between 7 and 16 μm.