Investigations on Mechanical Properties of Polyamide Parts Fabricated by Selective Laser Sintering Process

Duraform polyamide, a polymeric material, has grown extensive application in the fabrication of complex, light weight and solid parts for the aerospace and automotive industries. These end use parts require higher surface quality, strength, temperature capability and wear resistance. These parts can be easily fabricated with the use of selective laser sintering (SLS) and the adequacy of these selective laser-sintered parts for different applications depends on the mechanical properties. The mechanical properties of these parts can be governed by the setting of input parameters. In the present study, Duraform polyamide is used to fabricate different parts. A face-centered central composite design is used to optimize the process parameters in selective laser sintering. This design consists of five factors: laser power, bed temperature, layer thickness, scan spacing and orientation. With different set of experiments, the ultimate tensile strength (UTS), % elongation, yield strength (YS) and young’s modulus (YM) are measured as response measures. A set of different mathematical models are established using statistical analysis. ANOVA is employed to verify the feasibility of the different models. The optimal sintering parameters to enhance the mechanical properties are recognized with the application of desirability approach. Scan spacing was recognized as best relevant parameter that influences the UTS, % elongation, YS along with YM most significantly. From the experimentation, it can be further observed that parts fabricated with laser power of 40.71 W, bed temperature of 176°C, layer thickness of 0.09 mm, scan spacing of 0.15 mm and orientation of 90° will generates the parts having the maximum UTS, % elongation, YS and YM, respectively, and can be used as solid parts for the aerospace as well as the automotive industry.