用支撑材料直接墨水书写时的角精度
Corner accuracy in direct ink writing with support material
摘要：
能够控制嵌入颗粒的位置和取向的3D打印方法在细胞图案化和复合支架中具有很好的应用前景。基于挤出的增材制造技术，如熔融沉积成型和直接油墨写入，可能会在角落处出现颗粒图案化缺陷，这可能会阻碍角落处的细胞存活并产生意外的性能梯度。在这里，我们提出的模型，预测的行为沉积线在角落的中等粘度的油墨，这是由毛细作用和粘性耗散的影响。使用直接墨水书写与声电泳和基于Carbopol的支持凝胶，我们写多边形的牙科树脂为基础的复合油墨包含一个狭窄的分布在长丝的中心的微粒。拐角的内表面和外表面之间的拉普拉斯压力差驱动拐角平滑，其中拐角的内半径增加。双重沉积或在同一区域上印刷两次会导致角部膨胀，其中多余的油墨被转移到角部的外边缘。角部处的快速转弯产生振铃，其中载物台中的振动表现为打印路径中的振荡。在沉积后立即在角部处的颗粒分布中出现溶胀和振铃效应，而在打印结构有时间松弛后，平滑效应明显。当喷嘴返回写入相邻线时，它施加剪切应力，通过擦除松弛期间出现的缺陷来减轻角落处的微结构的不一致性。使用支撑浴代替逐层支撑抑制了微观结构角缺陷。
英文摘要：
3D printing methods which enable control over the position and orientation of embedded particles have promising applications in cell patterning and composite scaffolds. Extrusion-based additive manufacturing techniques such as fused deposition modeling and direct ink writing can experience particle patterning defects at corners which could hinder cell survival at corners and create unintended property gradients. Here, we propose models which predict the behavior of deposited lines at corners for moderate viscosity inks which are impacted by both capillarity and viscous dissipation. Using direct ink writing with acoustophoresis and a Carbopol-based support gel, we write polygons out of dental resin-based composite inks containing a narrow distribution of microparticles at the center of the filament. A Laplace pressure differential between the inner and outer surfaces of the corner drives corner smoothing, wherein the inner radius of the corner increases. Double deposition, or printing on the same area twice, drives corner swelling, wherein excess ink is diverted to the outer edge of the corner. Fast turns at corners produce ringing, wherein vibrations in the stage manifest in oscillations in the print path. Swelling and ringing effects are apparent in the particle distributions at corners immediately after deposition, while smoothing effects are apparent after the printed structure has had time to relax. When the nozzle returns to write a neighboring line, it imposes shear stresses which mitigate inconsistencies in microstructure at corners by erasing defects which appeared during relaxation. Using a support bath instead of layer-by-layer support suppresses microstructural corner defects.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
