Influence of forming conditions on the titanium model in rapid prototyping with the selective laser melting process

In order to evaluate the titanium model to be used for medical purposes in rapid prototyping with the selective laser melting process, the influence of forming conditions on the mechanical properties is investigated. The density and mechanical properties such as tensile and fatigue strengths of the model are measured. In the selective laser melting process, a pulsed yttrium aluminium garnet (YAG) laser with average power of 50 W and maximum peak power of 3 kW is used. The specimens for measuring density and mechanical properties are made from commercial pure titanium powders (grade 1) in a controlled atmosphere with argon gas. It is found that the relative density of the model is higher than 92 per cent and some powder particles remain within the solidified model. The scan speed affects the tensile strength strongly and the tensile strength is around 120 per cent of the standard value of the solid pure titanium when the scan speed is appropriate. However, the fatigue strength is low, about 10 per cent of the solid one, which is still to be improved by post-processing.