Vijayan Sindhu, Parthiban Pravien, Hashimoto Michinao
Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
Digital Manufacturing and Design Centre, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
Micromachines (Basel). 2021 Mar 13;12(3):302. doi: 10.3390/mi12030302.
PolyJet™ 3D printers have been widely used for the fabrication of microfluidic molds to replicate castable resins due to the ease to create microstructures with smooth surfaces. However, the microstructures fabricated by PolyJet printers do not accurately match with those defined by the computer-aided design (CAD) drawing. While the reflow and spreading of the resin before photopolymerization are known to increase the lateral dimension (width) of the printed structures, the influence of resin spreading on the vertical dimension (height) has not been fully investigated. In this work, we characterized the deviations in both lateral and vertical dimensions of the microstructures printed by PolyJet printers. The width of the printed structures was always larger than the designed width due to the spreading of resin. Importantly, the microstructures designed with narrow widths failed to reproduce the intended heights of the structures. Our study revealed that there existed a threshold width (') required to achieve the designed height, and the layer thickness (a parameter set by the printer) influenced the threshold width. The thresholds width to achieve the designed height was found to be 300, 300, and 500 μm for the print layer thicknesses of 16, 28, and 36 μm, respectively. We further developed two general mathematical models for the regions above and below this threshold width. Our models represented the experimental data with an accuracy of more than 96% for the two different regions. We validated our models against the experimental data and the maximum deviation was found to be <4.5%. Our experimental findings and model framework should be useful for the design and fabrication of microstructures using PolyJet printers, which can be replicated to form microfluidic devices.
由于PolyJet™ 3D打印机易于制造具有光滑表面的微结构，因此已被广泛用于制造微流控模具以复制可浇铸树脂。然而，PolyJet打印机制造的微结构与计算机辅助设计（CAD）图纸定义的结构并不完全匹配。虽然已知光聚合前树脂的回流和铺展会增加打印结构的横向尺寸（宽度），但树脂铺展对垂直尺寸（高度）的影响尚未得到充分研究。在这项工作中，我们对PolyJet打印机打印的微结构在横向和垂直尺寸上的偏差进行了表征。由于树脂的铺展，打印结构的宽度总是大于设计宽度。重要的是，设计宽度较窄的微结构未能再现结构的预期高度。我们的研究表明，存在一个达到设计高度所需的阈值宽度（'），并且层厚（打印机设置的一个参数）会影响阈值宽度。对于16、28和36μm的打印层厚，达到设计高度的阈值宽度分别为300、300和500μm。我们进一步针对该阈值宽度以上和以下的区域开发了两个通用数学模型。我们的模型对两个不同区域的实验数据的表示精度超过96%。我们根据实验数据对模型进行了验证，发现最大偏差<4.5%。我们的实验结果和模型框架对于使用PolyJet打印机设计和制造微结构应该是有用的，这些微结构可以复制以形成微流控装置。
