Experimental Investigation and Optimization of Laser Parameters on Tensile Strength of Sintered PP and PP/CNT Composite in Selective Laser Sintering

Selective laser sintering (SLS) is an additive manufacturing technology whereby parts are built through selective consolidation of a powder by a laser beam. Recently, Polypropylene (PP) has been used in the SLS because of its appropriate mechanical performance as well as low cost and density. In the SLS, laser parameters are very effective on the mechanical properties of the sintered parts. In this study, the effects of the laser parameters including power, the laser scanning speed, and the laser scanning pattern on the tensile strength of the sintered samples were experimentally investigated. The PP and PP/CNT (carbon nanotube) composites were used as raw materials and the results were compared. Taguchi method was employed as the experimental design, and optimal levels of parameters were extracted using signal-to-noise analysis. The main effects of factors and interactions were considered in this paper. The results show that the laser scanning pattern and the laser power have the most effects on the tensile strength of the produced samples. In addition, the comparison between the results of the experiments demonstrates an increase in the tensile strength, which is 15% in maximum value, by adding CNT to PP.