Investigation into the Crystalline Structure and sub-Tpm Exotherm of Selective Laser Sintered Polyamide 6

Selective Laser Sintering (SLS) has achieved a wide acceptance for direct manufacture of complex functional components. However, the performance of SLS part still needs to be improved, in which the crystalline structure plays an important role. Every crystalline form has specific properties, and the whole material behaviors have great relationships with the various species and crystalline structure. Therefore, this paper investigates crystalline structure of laser sintered Polyamide 6 (PA6) and quantifies the different HT-α and LT-α phases using thermal analysis. The results show that the sintered parts are uniformly characterized by a relatively stronger (2 0 0) and a weaker (0 0 2) diffraction peak. This crystalline structure variation is basically consistent for all SLS parts and independent of laser power. In addition, the sub-Tpm crystallization transition concerning α phase was found for SLS PA6 part, which is derived from the release of strain energy absorbed during SLS processing.