Effects of processing on microstructure and properties of SLS Nylon 12

By H. Zarringhalam, N. Hopkinson, N. Kamperman, J. Vlieger. 2006

282 citations recorded by the source corpus.

There currently exists the requirement to improve reproducibility and mechanical properties of SLS Nylon parts for rapid manufacturing (RM). In order to achieve this, further fundamental research is needed and this paper addresses this need by investigating effects of potential sources of the lack of reproducibility and reports effects in relation to crystal structure, microstructure, chemical structure (molecular weight) and mechanical properties. Different γ crystal forms were identified and related to the unmolten particle cores and the melted/crystallised regions of the microstructure. The melt point of the γ-form varied depending on processing conditions. Observable differences were also present when comparing the microstructure of the parts. Molecular weight of parts was significantly higher than virgin powder but used powder also showed an increase in molecular weight. This was related to improved elongation at break of parts built from the used powder, consistent with previous studies. Tensile strength showed some increase with machine parameters selected for improved strength but Young's modulus values were broadly similar.

Subfields: Automotive Engineering, Biomaterials, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/46058160ebac8bc1bb19ea66c93df5e12540ee26

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In Automotive Engineering

Citations in the corpus

Recycling of polyamide 12 based powders in the laser sintering process (2009, background): “recycled powder thermal properties and molecular weight (Zarringhalam et al., 2006).”
The effect of process conditions on mechanical properties of laser‐sintered nylon (2011, background): “More recent studies of mechanical properties also do not fully explore the range of process parameters ( Zarringhalam et al. , 2006”
On the difference in material structure and fatigue properties of nylon specimens produced by injection molding and selective laser sintering (2013, background): “Also, the influence of various process parameters such as energy density, cooling rate, scan pattern, layer orientation, delay time, etc has been analysed to find an optimal set of production parameters [7, 8, 9, 10, 11].”
Performance Limitations in Polymer Laser Sintering (2014, methodology): “Other studies note a 2-3× increase in molecular weight with used powder, consistent with an increase in viscosity; see Dotchev and Yusoff (2009), and Zarringhalam et al. (2006).”