Optimum sintering region for laser sintered nylon-12
Optimum sintering region for laser sintered nylon-12
复制标题
激光烧结尼龙 12 的最佳烧结区域
DOI：
10.1177/0954405411414994
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
N. Hopkinson
中科院分区：
文献类型：
--
作者：
M. Vasquez;B. Haworth;N. Hopkinson
众所周知，激光烧结尼龙-12的力学性能随着外加能量的增加而提高。然而，性能可以达到最大值，在此之后，附加能量的应用可能导致部分性能下降。据认为，这种下降的原因是额外的能量导致聚合物链降解或分子结构的其他变化。本文旨在利用热重分析（TGA）研究尼龙-12在加工过程中高能量密度条件下的热降解，并解释其力学性能的退化。主要发现是应用建模方法来预测尼龙-12激光烧结过程中达到的温度。结果表明，激光烧结机内的温度可达到300℃以上。TGA数据显示，在这些温度下，会发生质量损失，并可能导致机械性能崩溃。这项实际工作结合了差示扫描量热法和热重分析仪作为识别材料热转变的手段。术语“稳定烧结区”被提出作为激光烧结界的一个新概念，并且可以更好地理解工艺参数如何影响机器内构建的部件。此外，该概念可用于筛选潜在新聚合物的材料选择过程。与其他聚合物工艺（如注射成型）相比，激光烧结的一个局限性是对机器参数和零件性能之间关系的理解有限。这项工作旨在通过讨论暴露在高激光参数下的聚酰胺的热行为模式（包括降解）来提高这种理解。
It is well known that the mechanical properties of laser sintered Nylon-12 improve with increased applied energy. However properties can reach a maximum after which, the application of additional energy can a lead to a decline in part properties. It is thought that the reason for this decline is that the additional energy causes polymer chain degradation or other changes in molecular structure. This paper aims to use thermogravimetric analysis (TGA) to investigate the thermal degradation of nylon-12 and explain the deterioration of mechanical properties when high energy density conditions are applied during processing. The key findings are the application of modelling methods to predict the temperatures achieved during laser sintering of nylon-12. It is shown that temperatures in the laser sintering machine can achieve levels above 300°C. At these temperatures, TGA data show that mass loss occurs and could cause mechanical property breakdown. This practical work coupled differential scanning calorimetry and TGA as a means of identifying thermal transitions in the material. The term ‘stable sintering region’ is proposed as a novel concept for the laser sintering community, and can have implications for better understanding of how process parameters can affect parts built in the machine. In addition, the concept could be used in the material selection process when screening potential new polymers for the process. One limitation of laser sintering, compared to other polymer processes such as injection moulding, is the limited understanding of the connection between machine parameters and part properties. This work aims to improve that understanding by discussing the pattern of thermal behaviour, including degradation, seen in polyamide exposed to high laser parameters.
影响因子：
10.6
作者：
Majewski, C. E.;Hobbs, B. S.;Hopkinson, N.
通讯作者：
Hopkinson, N.