Processing and properties of glass bead particulate-filled functionally graded Nylon-11 composites produced by selective laser sintering

This article investigates the fabrication of functionally graded materials (FGMs) by selective laser sintering (SLS) of Nylon-11 composites filled with different volume fractions of glass beads (0-30%). The investigation involved a combination of experimental studies, theoretical modeling and numerical analysis. Optimal processing parameters for each composition were developed by design of experiments (DOE). These parameters were then compared with parameters predicted by numerical modeling. Specimens for tensile and compressive testing for each composition and for a ID FGM composition were fabricated and tested. The experimentally measured tensile and compressive moduli were compared with moduli predicted by Halpin's theoretical model and were found to be in excellent agreement. The results showed that the tensile and compressive modulus increases while strain at break and strain at yield decreases as a function of glass bead volume fraction. A finite element model for the compressive properties of the ID FGM specimen showed good agreement with experimentally measured values. Finally, to demonstrate the SLS-based FGM approach, two components exhibiting a one-dimensional functional gradient of particulate-filled polymer composites were fabricated. (c) 2006 Elsevier B.V. All rights reserved.