Purpose

Selective laser sintering (SLS) has passed other techniques, thanks to its high print resolution, its ability to print microscale geometries without any additional support, its surface quality and its long-term thermal stability. However, despite the many advantages of SLS compared to fusion deposition modelling, there are still today some limitations on the materials to be printed. A limit critical from an industrial point of view is the aging of PA12 powder, i.e. the degradation of its physical and chemical performances, due to the high temperatures and the long printing cycles, thus involving a decrease of the mechanical properties of the printed parts. The purpose of this study was to charaterize mechanically and dimensionally specimens printed in PA12 through SLS by means of virgin or aged powder, i.e. powder just used for five printing cycles.

Design/methodology/approach

To achieve this aim, a set of specimens were designed, built, measured and mechanically tested; the obtained results were put into relationship with the values of the process parameters used to print them. Statistical tools to design the experiments and to analyse the obtained results were used.

Findings

The results show that the SLS process carried out through a Sintratec machine on PA12 powder has a good repeatability. To obtain the best dimensional and mechanical performances, it is needed to use virgin powder and place the part in the central zone of the printing area.

Originality/value

There are no scientific articles dealing with the influence of both the aging of the powder and the manufacturing parameters on the dimensional and mechanical characterization of specimens printed with SLS technique in PA12.

中文翻译：

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PA12选择性激光烧结的研究：尺寸精度和机械性能

目的

选择性激光烧结 (SLS) 已经超越了其他技术，这得益于其高打印分辨率、无需任何额外支持即可打印微尺度几何形状的能力、其表面质量和长期热稳定性。然而，尽管与熔融沉积建模相比，SLS 有许多优势，但今天要打印的材料仍然存在一些限制。从工业角度来看，一个关键的限制是 PA12 粉末的老化，即由于高温和长打印周期导致其物理和化学性能的退化，从而导致打印部件的机械性能下降。本研究的目的是通过原始或老化粉末通过 SLS 对 PA12 中打印的机械和尺寸样本进行表征，即

设计/方法/方法

为了实现这一目标，设计、建造、测量和机械测试了一组试样；获得的结果与用于打印它们的工艺参数值相关联。使用统计工具来设计实验和分析获得的结果。

发现

结果表明，通过 Sintratec 机器对 PA12 粉末进行的 SLS 工艺具有良好的重复性。为了获得最佳的尺寸和机械性能，需要使用原始粉末并将零件放置在打印区域的中心区域。

原创性/价值

没有科学文章涉及粉末老化和制造参数对在 PA12 中使用 SLS 技术打印的样品的尺寸和机械特性的影响。