Impact of controlled prewetting on part formation in binder jet additive manufacturing
Impact of controlled prewetting on part formation in binder jet additive manufacturing
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DOI：
10.1016/j.addma.2023.103619
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发表时间：
2023-05-25
影响因子：
11
通讯作者：
Crane，Nathan B.
中科院分区：
文献类型：
--
作者：
Inkley，Colton G.;Lawrence，Jacob E.;Crane，Nathan B.
粘合剂喷射是通过喷墨打印选择性地沉积粘合剂来粘合粉末的增材制造工艺。然后通过烧结和/或渗透提取和致密化该部件。该工艺提供了低成本和快速构建速率，但由于烧结后的残余孔隙率，性能可能很差。喷墨印刷工艺可通过产生大孔而促成这种残余孔隙率。液滴动能将一些粉末颗粒从床层中逐出，并重新排列其他粉末颗粒。粒子喷射和重排理论上创建粘合剂喷射零件的多孔区域。在这项工作中，少量的水分被添加到打印前的传播粉末和零件形成的影响，部分属性，并与不同的液滴间距，液滴速度和打印频率测量的打印参数。通过在层铺展和粘合剂印刷之间向粉末施加雾化流体混合物来添加水分。流体混合物部分蒸发，但留下稳定的残余物以增加凝聚力并增强渗吸。添加到粉末中的水分增加了用于线形成的液滴间距范围，同时减少了颗粒喷射、粉末重排以及层和多层部件中的球化。过多的水分添加会降低打印线的有效饱和度，但3D部件中的饱和度受到的影响较小。在印刷品的前几层中增加的表面粗糙度也通过预润湿来减轻。高速X射线成像验证预湿减少颗粒喷射和重排。
Binder jetting is an additive manufacturing process that bonds powder through selectively depositing binder by inkjet printing. The part is then extracted and densified by sintering and/or infiltration. The process offers low costs and fast build rates, but properties can be poor due to residual porosity after sintering. The inkjet printing process may contribute to this residual porosity by creating large pores. The droplet kinetic energy ejects some powder particles from the bed and rearranges others. Particle ejection and rearrangement are theorized to create porous regions in binder-jetted parts. In this work, small amounts of moisture are added to the spread powder before printing and the impact on part formation, part properties, and printing parameters measured with varied droplet spacing, droplet velocity, and print frequency. Moisture is added by applying an atomized fluid mixture to the powder between layer spreading and binder printing. The fluid mixture partially evaporates but leaves a stable residue to increase cohesion and enhance imbibition. Moisture addition to the powder increases the range of droplet spacings for line formation while reducing particle ejection, powder rearrangement, and balling in layer and multilayer parts. Excessive moisture addition decreases the effective saturation of printed lines, but saturation in 3D parts is less impacted. Increased surface roughness in the first few layers of a print was also mitigated with prewetting. High-speed X-ray imaging verified prewetting reduction in particle ejection and rearrangement.