【作者】 汪洋；

【导师】 陈云飞； 吕晓俊；

【作者基本信息】 东南大学 ， 机械工程（专业学位）， 2021， 硕士

【摘要】 复杂三维微纳结构在微机电系统、生物医疗、能源动力、智能穿戴、卫生保健等领域有着巨大的产业需求。然而现有的微纳3D打印系统无论在打印精度方面,还是在打印质量、效率、成本、材料等方面还难以满足高精度、低成本、批量化制造复杂三维微纳结构的工业级应用的需求。投影微立体光刻技术是一种低成本、高效率的增材制造技术,能够制造具有微米级结构和亚微米精度的各种高度复杂的三维结构。为突破现有3D打印系统的打印精度,本文着重对投影微立体光刻系统的水平打印精度和垂直打印精度进行了研究。在水平打印精度方面,基于DMD动态掩膜设计出了满足高精度固化要求的照明系统和投影系统,其中投影系统的光学分辨力达到亚微米尺度;在垂直打印精度方面,通过仿真和实验研究了液态光敏树脂在微米级层厚下的自由液面流平特征,在此基础上提出了约束液面流平方案,即通过设置压模模块来平整树脂液面,并在机械结构上予以实现,解决了自由液面流平方案中层厚不理想的问题。此外,本文还对投影微立体光刻系统中的控制系统进行了初步设计,并完成了实验样机的搭建。最后通过实验对样机的打印性能进行了验证。根据光学系统的设计参数和微位移平台的定位精度,理论上实验样机的水平打印精度和垂直打印精度均可以达到1μm,在实际打印过程中,打印精度不可避免地会受到树脂的物理化学特性、温度、曝光时间、机械误差等多方面因素的影响。为探究样机的实际打印精度,实验中对不同宽度的长板特征和不同厚度的横梁特征进行了打印。根据实验结果可知,理想线宽为5μm的长板在水平方向上的尺寸误差最小为1.8μm,理想厚度为10μm的横梁在垂直方向上的尺寸误差最小为2.6μm。在此打印精度条件下,本文尝试性打印出最小特征尺寸为10μm的蜂窝结构,初步验证了所研制样机对复杂三维微纳结构的制造能力。更多还原

【Abstract】 Complex three-dimensional(3D)micro/nanostructures have huge industrial demands in the fields of micro-electro-mechanical system(MEMS),biomedicine,new energy,wearable devices,healthcare and so on.However,the existing 3D printing system is still difficult to meet the requirements of industrial applications for high-precision,low-cost,and batch manufacturing of complex 3D micro/nanostructures in terms of printing resolution,print quality,speed,cost,and materials.Projection micro-stereolithography(PμSL)is a low cost,high throughput additive fabrication technique capable of manufacturing a variety of highly complex,3D structures with microscale architecture and submicron precision.In order to break through the printing resolution of the existing 3D printing system,the horizontal printing resolution and vertical printing resolution of the PμSL system were studied.In terms of the horizontal printing resolution,the optical system consisting of the illumination system and projection system was designed based on the digital micromirror device(DMD)to meet the requirements of highprecision imaging.The optical resolution of the designed projection system reaches submicron.In the aspect of vertical printing resolution,the leveling characteristics of the free liquid surface were studied when the thickness of the resin layer is tens of microns through simulation and experiment.An effective scheme for leveling resin surface by constraining resin surface was proposed and realized on the mechanical structure,which solved the problem of unsatisfactory layer thickness in the former scheme.In addition,the control system of the PμSL system was designed preliminarily,and the experimental prototype was constructed.Finally,the printing performance of the prototype was verified by experiments.According to the design parameters of the optical system and the positioning accuracy of the micro-displacement platform,the printing resolution of the PμSL system can reach 1um in both horizontal and vertical directions theoretically.In the actual manufacturing process,the printing resolution will inevitably be affected by many factors such as the physical-chemical characteristics of resin,temperature,exposure time,mechanical error,etc.In order to explore the actual printing accuracy of the prototype,long plates of different widths and beams of different thicknesses were printed in the experiment.According to the experimental results,the minimum size error of the long plate with an ideal width of 5μm in the horizontal direction is1.8μm,and the minimum size error of the beam with an ideal thickness of 10μm in the vertical direction is 2.6μm.Based on the current printing accuracy,a honeycomb structure with a minimum feature size of 10μm was successfully printed,which preliminarily verified the manufacturing capability of the constructed prototype for the complex 3D micro/nanostructures.更多还原