Effect of anisotropy in the build direction and laser-scanning conditions on characterization of short-glass-fiber-reinforced PBT for laser sintering

Copolymer poly(butylene terephthalate) with 30- wt% short glass fiber (SGF) added was used to evaluate the dependence of the properties of specimens manufactured by selective laser sintering (SLS) and the influence of laser-irradiation conditions on build direction. The degree of orientation of SGFs in SLS is ranked in descending order of roller-movement direction, vertical direction in the powder-bed plane, and direction of lamination-layer thickness. Moreover, the influence of fiber orientation on mechanical properties, thermal properties, and shrinkage ratio was found to be remarkable. In the case of the double-scan method, in comparison to the single-scan case, while thermal degradation was suppressed, porosity was reduced, and mechanical properties were improved. In addition, degree of crystallinity of the SLS specimens increased, and heat-deflection temperature increased slightly. Furthermore, in regard to roller-movement direction and lamination-layer thickness direction, the trends of shrinkage ratio differ in the cases of the single- and double-scan scanning methods.