Impact of inkjet printing parameters and environmental conditions on formation of 2D and 3D binder jetting geometries
Impact of inkjet printing parameters and environmental conditions on formation of 2D and 3D binder jetting geometries
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DOI：
10.1016/j.jmapro.2021.09.024
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发表时间：
2021-09-24
影响因子：
6.2
通讯作者：
Crane, Nathan B.
中科院分区：
文献类型：
--
作者：
Colton, Trenton;Inkley, Colton;Crane, Nathan B.
虽然粘合剂喷射增材制造（BJAM）具有巨大的潜力，但其实施受到成品零件缺陷的限制。需要更好地理解打印参数如何影响打印部件的质量。先前关于BJAM打印中的液滴/粉末相互作用的工作集中在单独的线上，这项工作表明，成功的层形成有利于比单独的线中可行的更大的液滴间距。当印刷层时，第一印刷层明显比铺展床粗糙，表明明显的粉末喷射。然而，在印刷1-4个附加层之后消除了这种差异。这些结果表明，之前的印刷层对液滴冲击和吸胀有很大影响，并且简单的液滴或线几何形状对于测试印刷参数无效。第一层的粗糙度可能有助于在层之间观察到的大孔。本文进一步研究了关键打印参数（包括层厚度、液滴/线间距和液滴到达间隔时间）对2D和3D零件的有效饱和度和表面粗糙度的影响。在测试条件下，液滴到达间隔时间（打印频率）对表面粗糙度和饱和度的影响可忽略不计。印刷层的表现类似的液滴间距值可比的液滴直径（44 μ m）。相比之下，60 μ m的液滴间距产生了显著较低的饱和度。有效饱和度通常随着层数的增加而增加。印刷过程中的环境湿度暴露被证明对印刷结果的影响可以忽略不计，尽管来自蒸汽暴露的较高水分水平显著改变饱和度。在涂布前干燥粉末减少了印刷部件的变化。所有试验均基于气体雾化的~ 22 μ m 316 SS粉末。
While Binder Jet Additive Manufacturing (BJAM) has great potential, its implementation is limited by defects in the finished parts. An improved understanding of how printing parameters impact the quality of the printed parts is needed. Prior work on the droplet/powder interactions in BJAM printing focused on individual lines, this work shows that successful layer formation favors larger droplet spacing than is viable in individual lines. When printing layers, the first printed layer was significantly rougher than the spread bed indicating significant powder ejection. However, this difference was eliminated after printing 1-4 additional layers. These results show that prior printed layers have a strong impact on droplet impact and imbibition and that simple droplet or line geometries are not effective for testing printing parameters. The roughness of the first layer may contribute to large pores observed between layers. This paper further examines the impact of key printing parameters including layer thickness, droplet/line spacing, and droplet inter-arrival time on the effective saturation and surface roughness of 2D and 3D parts. The droplet inter-arrival time (print frequency) had negligible impact on surface roughness and saturation under the conditions tested. Printed layers behaved similarly at droplet spacing values comparable to the droplet diameter (44 mu m). In contrast, droplet spacing of 60 mu m, produced substantially lower saturation. Effective saturation generally increases with increased number of layers. Ambient humidity exposure during printing is shown to have a negligible impact on printing outcomes though higher moisture levels from steam exposure dramatically alter saturation. Drying powder before spreading reduced variation in the printed parts. All tests were based on gas atomized -22 mu m 316 SS powder.