Taguchi-based optimization of mechanical properties and dimensional accuracy of selective laser-sintered polyamide-12

Abstract

Studies found that parts produced using selective laser sintering (SLS) exhibit non-uniform surface morphology and lower physical properties. These characteristics are associated with decreased tensile strength and overall performance of polyamide-12 (PA-12) manufactured through conventional SLS. This study aims to extend existing knowledge by applying the Taguchi optimization method to investigate the effects of SLS process parameters on the mechanical properties and dimensional accuracy of PA-12. The study focuses on PA-12 material composition comprising virgin, reheated, and recycled powders. Laser power and layer thickness were also investigated, with layer thickness identified as the dominant processing parameter. The test specimens were produced using conventional SLS and tested for tensile strength, impact resistance, hardness, surface roughness, compression, torsion, surface morphology, and dimensional accuracy. Dimensional accuracy was evaluated using a coordinate measuring machine (CMM), and material bonding was checked using a scanning electron microscope (SEM). The optimum performance was obtained with 100% virgin PA-12, applying a laser power of 60 W and a layer thickness of 0.06 mm. The combination of parameters led to better mechanical and surface quality, as well as dimensional accuracy. Material Composition A1, mainly composed of virgin material, showed the best overall performance in the mechanical tests conducted. It was found that the most important parameters governing part performance were laser power and layer thickness. The recorded dimensional variations of 0.14 mm and 0.11 mm along the X and Y axes, respectively, were within the permissible tolerance range, demonstrating adherence and marginal improvement beyond the manufacturer's defined limits. The results show that the correct selection of material formulations and the optimization of processing parameters can significantly improve the accuracy, structural integrity and overall performance of SLS-fabricated PA-12 products.