Experimental Evaluation of Polyphenylsulfone (PPSF) Powders as Fire-Retardant Materials for Processing by Selective Laser Sintering

Abstract

Additive manufacturing has progressed rapidly, and the unique attributes of the layer-wise material consolidation are attracting ever increasing application potentials in critical sectors such as medical and aerospace industries. A lack of materials options has been the main bottleneck for the much wider uptake of these promising new technologies. Inventing new material alternatives has been central to most of the research attention in additive manufacturing in recent times. The current research is focused on evaluating the polyphenylsulfone polymer powders for the first time as fire-resistant candidate materials for processing by selective laser sintering, the most promising additive processing method for polymeric material systems. Experimental evaluations were undertaken based on a selective laser sintering test bed. Single layer and multi-layer samples were produced for microstructural and mechanical characterisations. The microstructural evaluations and the mechanical property results indicate sufficient intra- and inter-layer consolidation together with reasonable tensile property responses. The lower viscosity and thermal conductivity characteristics rendered lower tensile strengths, which will require some further attention in the future, for better consolidation and mechanical properties.

Thermal Intra-Layer Interaction of Discretized Fractal Exposure Strategies in Non-Isothermal Powder Bed Fusion of Polypropylene

“…In contrast, the occurrence of a consolidation phase in non-isothermal LPBF [3,6] is inherently restricted due to a considerable supercooling and the corresponding rapid crystallization of the polymer melt [3,6], depending on the emerging cooling rate [25]. Existing research on support-bound LPBF at reduced build chamber temperatures is predominantly based on parameter adaptions of existing linear exposure strategies [7][8][9]26,27]. To allow for support-free non-isothermal LPBF of polymers, the proposed application of fractally sequenced, locally quasi-simultaneous exposure strategies has been described [3,6], representing the foundation for extending the consolidation phase in non-isothermal processing based on the repetitive exposure of distinct segments.…”