超声振动整体型腔式微流控芯片注塑成型研究

发布时间：2018-07-26 19:46

【摘要】：MEMS技术的蓬勃发展,使具有微结构特征的制件在众多领域中获得了更为广泛的应用。目前,虽然微注塑成型工艺可以实现微结构制件的低成本、短周期、批量化生产的要求,可是随着对微结构成型质量要求的不断提高,通过单一的成型手段已经无法满足实际需求。在超声技术迅速发展的基础上,不少学者将目光投向了超声振动在微注塑领域内的应用,并通过实验研究证实了超声振动在一定程度上可以降低聚合物熔体的粘度、提高其流动性能。因此本文选择具有广阔应用前景的微流控芯片作为研究载体,对超声振动在注塑成型中对微结构成型质量的影响进行探索。首先,在讨论了注塑成型中模具微结构的填充方式之后,分析进浇方向与模具微结构分布方向的夹角对微流控芯片微沟槽的成型质量造成的影响。在此基础上,对微流控芯片的微沟槽分布样式进行了设计,以研究超声振动对不同尺寸、不同分布情况模具微结构的充模效果的影响。其次,在总结和归纳前人工作的基础上,分析了不同作用方向和作用形式的超声振动对注塑成型微结构制品成型质量的影响机理,提出了将整体作用式的超声振动引入到注塑成型模具的型腔中,设计了包含不同振动方向的的超声振动辅助微注塑成型模具,以期进行型腔振动方向对微流控芯片塑件成型质量影响的研究。最后,通过超声振动辅助微注塑成型实验,研究了超声振动参数对PMMA材料微流控芯片成型质量的影响。结果表明,在成型过程的不同阶段对塑件施加超声振动后,微流控芯片塑件的成型质量会产生不同程度的变化。当成型过程处于填充阶段时,施加超声振动后,随着超声功率的增加和振动时间在一定范围内的延长,微流控芯片微沟槽的上槽宽度会出现不断缩小的迹象。但是当振动时间延长到保压阶段结束以后时,微沟槽的上槽宽度将会开始出现增大的反弹现象,并容易引起微流控芯片塑件表面的振纹,振纹会随着超声功率的增加而逐渐地向塑件中央汇聚。当施加的超声振动开始于保压完成后的阶段时,塑件表面上也会出现具有同样变化规律的振纹。这一系列的现象说明,在注塑成型PMMA材料微流控芯片的过程中引入超声作用时,超声振动施加的阶段和振动时间的选取,对塑件的成型质量起着至关重要的作用。
[Abstract]:With the rapid development of MEMS technology, microstructural parts have been widely used in many fields. At present, although the microinjection molding process can realize the requirements of low cost, short period and mass production of microstructural parts, but with the continuous improvement of the requirements for the quality of microstructural molding, Through a single molding method can no longer meet the actual needs. On the basis of the rapid development of ultrasonic technology, many scholars have turned their eyes to the application of ultrasonic vibration in the field of microinjection molding, and it has been proved that ultrasonic vibration can reduce the viscosity of polymer melt to a certain extent. Improve its fluidity. Therefore, the microfluidic chip with broad application prospect is selected as the research carrier in this paper, and the influence of ultrasonic vibration on the quality of microstructural molding in injection molding is explored. Firstly, after discussing the filling mode of mold microstructure in injection molding, the influence of the angle between the direction of injection pouring and the direction of distribution of die microstructure on the forming quality of microgroove of microfluidic chip is analyzed. On this basis, the microgroove distribution pattern of microfluidic chip is designed to study the effect of ultrasonic vibration on mold filling effect with different size and distribution. Secondly, on the basis of summarizing and summarizing the previous work, the influence mechanism of ultrasonic vibration of different action direction and action form on the molding quality of injection molding microstructural products is analyzed. In this paper, the integral ultrasonic vibration is introduced into the cavity of the injection mould, and the ultrasonic vibration assisted micro-injection molding mould with different vibration directions is designed. The purpose of this paper is to study the effect of cavity vibration direction on molding quality of microfluidic chip. Finally, the influence of ultrasonic vibration parameters on the molding quality of PMMA microfluidic chip was studied by ultrasonic vibration assisted microinjection molding experiment. The results show that the molding quality of the microfluidic chip will change in varying degrees after ultrasonic vibration is applied to the plastic parts in different stages of the molding process. When the molding process is in the filling stage, with the increase of ultrasonic power and the extension of vibration time in a certain range, the upper slot width of microfluidic chip microgroove will decrease continuously after the application of ultrasonic vibration. However, when the vibration time is extended to the end of the holding stage, the upper groove width of the microgroove will begin to increase, which will easily cause the vibration on the surface of the microfluidic chip. The vibration will gradually converge to the center of the plastic parts with the increase of ultrasonic power. When the applied ultrasonic vibration begins at the stage after the completion of the holding pressure, there will also appear the same pattern of vibration on the surface of the plastic parts. This series of phenomena shows that when ultrasonic action is introduced into the microfluidic chip of PMMA materials for injection molding, the selection of the stage of ultrasonic vibration and the selection of vibration time play an important role in the molding quality of plastic parts.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN492

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