PMMA微流控芯片注射成型多目标优化实验研究

Experimental study on multi-objective optimization of PMMA microfluidic chip injection molding

随着微流控技术的不断发展和聚合物材料的广泛应用,注射成型技术因其快速、低成本、大批量的生产等优势而成为聚合物微流控芯片成型制造的主要方式之一,但也存在微结构成型难、残余应力与宏观变形等问题。为表征聚合物微流控芯片成型能力、研究工艺参数对成型质量的影响,采用正交实验研究熔体温度、注射压力、注射速度、保压压力和保压时间对聚甲基丙烯酸酯(PMMA)微流控芯片微通道复制度、残余应力、宏观翘曲变形三种指标的影响规律,并利用灰色关联分析法对三种指标进行多目标优化得到最优工艺参数。研究结果表明:影响微通道复制度最主要的因素是注射速度和熔体温度,影响残余应力与翘曲变形最主要的因素是熔体温度;利用正交实验对三种指标优化得到的最优参数存在差异,而利用灰色关联分析方法进行多目标优化得到了微通道复制度高、残余应力小和翘曲变形小的高质量芯片。最优注射成型工艺参数如下:熔体温度为245℃、注射压力为160 MPa、注射速度为50 cm3/s、保压压力为70 MPa和保压时间为5 s。

With the continuous development of microfluidic technology and the wide application of polymer materials,injection molding technology has become one of the main ways of polymer microfluidic chip molding and manufacturing because of its advantages of fast speed,low cost and mass production.However,there are also some problems such as difficulty in forming microstructure,residual stress and macroscopic deformation.In order to characterize the molding ability of polymer microfluidic chip and study the influence of process parameters on molding quality,the influence of melt temperature,injection pressure,injection speed,holding pressure and holding time on microchannel complex system,residual stress and macroscopic warp deformation of polymethacrylate(PMMA)microfluidic chip was studied by orthogonal experiment.The optimal parameters were obtained by multi-objective optimization of the three indexes using grey correlation analysis method.The results show that the injection speed and melt temperature are the most important factors affecting the microchannel replication,and the melt temperature is the most important factor affecting the residual stress and warpage deformation.The optimum parameters of the three indexes are different from each other by orthogonal experiment,and the high quality chip with high complex microchannel system,low residual stress and small warpage deformation is obtained by multi-objective optimization using grey correlation analysis method.The optimal parameters are as follows.The melt temperature is 245℃,the injection pressure is 160 MPa,the injection speed is 50 cm3/s,the pressure holding pressure is 70 MPa and the pressure holding time is 5 s.