[en] The uneven temperature field caused by the local instantaneous heating of the laser generates the thermal stress during the selective laser sintering. The stress causes the deformation of parts, affecting the precision and mechanical properties. However, it’s difficult to directly measure the stress history and deformation behavior during processing through experimental methods due to its ultra-high temperature and closed cavity. In this paper, the effects of laser power and scanning speed on the stress field and deformation of polyamide 6 by selective laser sintering were systematically investigated. The results showed that as the laser power increased or the scanning speed decreased, the z-direction stress and deformation of the specimens increased. Based on the inherent strain method, the deformation behavior of large-size parts was evaluated and in good agreement with experiments, which can guarantee the accuracy of the model and predict the deformation of parts. (paper)

[en] During the selective laser sintering process, the sintering behavior between powders is mainly affected by thermal effect. There are a large number of process parameters influencing the variation of temperature and molten pool, of which the laser density and scanning speed play a crucial role in determining the performance of the parts. In this paper, the effects of laser density and scanning speed on the precision and strength of polyamide 6 selective laser sintering parts were systematically investigated. The results show that with the increase of energy density, the positive dimensional deviation of the parts in three directions increases gradually, and the tensile strength increases at beginning and then decreases. When the laser power and scanning speed were changed, the tensile strength of the parts varied between 5.62 MPa and 58.74 MPa. (paper)