Methodology for mechanical property optimization of selective laser sintered parts using design of experiments

Selective laser sintering (SLS) is a form of additive manufacturing progressively used to manufacture end-use parts for industries including aerospace, automobile and biomedical. Machine settings, laser settings, and powder properties are all input parameters that affect the dimensional quality and mechanical properties of the produced SLS parts. A key challenge to successfully manufacturing SLS parts is learning how to control these parameters and finding the optimal settings such that desired mechanical properties are robustly achieved. This thesis proposes a design of experiments (DOE) based methodology to optimize mechanical properties of SLS parts. The study performs a DOE on three design variables (fill laser power, outline laser power, scan spacing) with three levels and measures six response variables (tensile strength, tensile modulus, tensile elongation-at-break, density, hardness, surface roughness). Experiments are performed using a work material of ALM PA 650 unfilled nylon 12 performance polyamide blend. The effects of the selected parameters on different part quality metrics are analyzed and discussed. A confirmatory test to prove the optimized model is performed and evaluated.