以一种微流控微反应器塑件为对象, 提出了用于微塑件整平的等温热压工艺, 研究了等温热压工艺对平板微塑件的整平机理。建立了描述该工艺的弹塑性数学模型, 计算分析了外加压力和温度对塑件表面形貌的影响。综合考虑塑件整平效果和微结构保形, 开展等温热压整平工艺实验, 分析了关键工艺参数对器件整平精度的影响。研究结果表明: 与压力载荷相比, 热载荷对不平度的改善效果更明显; 由于塑件端部区域受力面积大, 其两端变形量均大于中间反应腔的变形量。在相同压力条件下, 70 ℃时平面度和不平度的变化率均为最高。通过工艺优化, 微反应器塑件平面度提高到了10 μm内, 最大变化率可达72.7%; 而不同区域的不平度变化率为3.50%~53.50%, 微结构尺寸变化可控制在5 μm 以下。本文研究成果对提高平板微塑件平整精度有借鉴作用。

An isothermally hot-embossing methodology was proposed for the flattening of plastic microreactors. The flattening principles of a plane plastic microreactor by the isothermally hot-embossing methodology were researched and an elastic-plastic model was established to describe the deformation process. The influences of temperature and pressure on the topography of plastic microparts were quantitatively analyzed. By considering the flattening effect and microstructure of the plastic microreactor, the effect of main technological parameters on the flattening accuracy was analyzed by the isothermally hot-embossing methodology. The result indicates that the influence of thermal load on flattening degree is more obvious than that of the external pressure. The deformations at the ends of microreactor are much larger than that of the middle chamber owing to the larger contact area at the ends. The changing rates of flatness and waviness come to the maximum value when the temperature is 70 ℃ at the same pressure. After optimization, the changing rate of flatness achieves to 72.7% and the flatness of the microreactor is improved within 10 μm by the hot embossing technology. Moreover, the changing rate of waviness ranges from 3.50% to 53.5% at different regions of plastic microparts and the deformation of the microstructure size is controlled within 5 μm. The study is beneficial to improrement of the precision of flat plastic microparts.