Ai Jia-Ruey, Vogt Bryan D
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 USA.
Prog Addit Manuf. 2022;7(5):1009-1021. doi: 10.1007/s40964-022-00275-w. Epub 2022 Feb 24.
Print conditions for thermoplastics by filament-based material extrusion (MatEx) are commonly optimized to maximize the elastic modulus. However, these optimizations tend to ignore the impact of thermal history that depends on the specimen size and print path selection. Here, we investigate the effect of size print path (raster angle and build orientation) and print sequence on the mechanical properties of polycarbonate (PC) and polypropylene (PP). Examination of parallel and series printing of flat () and stand-on () orientation of Type V specimens demonstrated that to observe statistical differences in the mechanical response that the interlayer time between printed roads should be approximately 5 s or less. The print time for a single layer in XY orientation is much longer than that for a single layer in orientation, so print sequence only impacts the mechanical response in the orientation. However, the specimen size and raster angle did influence the mechanical properties in orientation due to the differences in thermal history associated with intralayer time between adjacent roads. Moreover, all of these effects are significantly larger when printing PC than PP. These differences between PP and PC are mostly attributed to the mechanism of interface consolidation (crystallization vs. glass formation), which changes the requirements for a strong interface between roads (crystals vs. entanglements). These results illustrate how the print times dictated by the print path layout impact observed mechanical properties. This work also demonstrated that the options available in some standards developed for traditional manufacturing will change the quantitative results when applied to 3D printed parts.
The online version contains supplementary material available at 10.1007/s40964-022-00275-w.
基于长丝材料挤出（MatEx）的热塑性塑料打印条件通常会进行优化，以最大化弹性模量。然而，这些优化往往忽略了热历史的影响，而热历史取决于试样尺寸和打印路径选择。在此，我们研究了尺寸打印路径（光栅角度和构建方向）以及打印顺序对聚碳酸酯（PC）和聚丙烯（PP）力学性能的影响。对V型试样的平面（）和直立（）方向的平行和串联打印进行检查表明，要观察到力学响应的统计差异，打印道之间的层间时间应约为5秒或更短。XY方向单层的打印时间比方向单层的打印时间长得多，因此打印顺序仅影响方向的力学响应。然而，由于相邻道之间层内时间相关的热历史差异，试样尺寸和光栅角度确实会影响方向的力学性能。此外，打印PC时所有这些影响都比打印PP时大得多。PP和PC之间的这些差异主要归因于界面固结机制（结晶与玻璃形成），这改变了道之间强界面的要求（晶体与缠结）。这些结果说明了打印路径布局所规定的打印时间如何影响观察到的力学性能。这项工作还表明，一些为传统制造制定的标准中可用的选项应用于3D打印部件时会改变定量结果。
在线版本包含可在10.1007/s40964-022-00275-w获取的补充材料。
