Sousa João, Teixeira Paulo F, Hilliou Loïc, Covas José A
Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal.
Micromachines (Basel). 2023 Jul 26;14(8):1496. doi: 10.3390/mi14081496.
The main objective of this work is to validate an in-line micro-slit rheometer and a micro-extrusion line, both designed for the in-line monitoring and production of filaments for 3D printing using small amounts of material. The micro-filament extrusion line is first presented and its operational window is assessed. The throughputs ranged between 0.045 kg/h and 0.15 kg/h with a maximum 3% error and with a melt temperature control within 1 °C under the processing conditions tested for an average residence time of about 3 min. The rheological micro slit is then presented and assessed using low-density polyethylene (LDPE) and cyclic olefin copolymer (COC). The excellent matching between the in-line micro-rheological data and the data measured with off-line rotational and capillary rheometers validate the in-line micro-slit rheometer. However, it is shown that the COC does not follow the Cox-Merz rule. The COC filaments produced with the micro-extrusion line were successfully used in the 3D printing of specimens for tensile testing. The quality of both filaments (less than 6% variation in diameter along the filament's length) and printed specimens validated the whole micro-set-up, which was eventually used to deliver a rheological mapping of COC printability.
这项工作的主要目标是验证一种在线微狭缝流变仪和一条微挤出生产线，二者均设计用于使用少量材料对3D打印用长丝进行在线监测和生产。首先介绍了微长丝挤出生产线，并评估了其操作窗口。在所测试的加工条件下，平均停留时间约为3分钟，产量范围在0.045 kg/h至0.15 kg/h之间，最大误差为3%，熔体温度控制在1℃以内。然后使用低密度聚乙烯（LDPE）和环烯烃共聚物（COC）对流变微狭缝进行了介绍和评估。在线微流变数据与离线旋转流变仪和毛细管流变仪测量的数据之间的出色匹配验证了在线微狭缝流变仪。然而，结果表明COC并不遵循Cox-Merz规则。用微挤出生产线生产的COC长丝成功用于3D打印拉伸试验样品。两种长丝的质量（沿长丝长度方向直径变化小于6%）和打印样品验证了整个微装置，最终该装置用于绘制COC可打印性的流变图。
