Statistical Evaluation of Laser Energy Density Effect on Mechanical Properties of Polyamide Parts Manufactured by Selective Laser Sintering

Selective laser sintering (SLS) is a rapid manufacturing technology that builds layer-by-layer solid object from particulate materials. Nowadays there are materials that are used to produce prototypes and end-user parts. Powders might be made from metals, ceramics, polymers, and composites. The union or fusion of the particles is made by the energy provided by a heated environment and a laser beam. Parts are built based on data extracted from its CAD design. The process has many variables that directly affect the mechanical properties of the parts. One important and direct processing parameter is laser energy density. This work evaluated the effect of the variation of the energy density in the mechanical properties of a polymeric material by changing laser beam speed and average power. The analyzed variables were stress at 10% of elongation, flexural modulus, and density of the samples built with polyamide 2200 (PA2200-EOSINT) using a CO2 laser (10 W). Specimens obtained by combination of different laser powers (2.7, 3.4, and 4.1 W) and laser scan speeds (39.0, 44.5, and 50.0 mm/s) were submitted to flexural tests. Additionally, volumetric density was calculated with mass and physical dimensions of specimens, and micrograph were taken using scanning electron microscope to analyze the changes of the sintering degree. The results indicated that laser power had more influence over density and mechanical properties than scan speed. The microstructures presented good correlation with the statistical results. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 2910-2919, 2009