【摘要】：MEMS技術(shù)的蓬勃發(fā)展,使具有微結(jié)構(gòu)特征的制件在眾多領(lǐng)域中獲得了更為廣泛的應(yīng)用。目前,雖然微注塑成型工藝可以實現(xiàn)微結(jié)構(gòu)制件的低成本、短周期、批量化生產(chǎn)的要求,可是隨著對微結(jié)構(gòu)成型質(zhì)量要求的不斷提高,通過單一的成型手段已經(jīng)無法滿足實際需求。在超聲技術(shù)迅速發(fā)展的基礎(chǔ)上,不少學(xué)者將目光投向了超聲振動在微注塑領(lǐng)域內(nèi)的應(yīng)用,并通過實驗研究證實了超聲振動在一定程度上可以降低聚合物熔體的粘度、提高其流動性能。因此本文選擇具有廣闊應(yīng)用前景的微流控芯片作為研究載體,對超聲振動在注塑成型中對微結(jié)構(gòu)成型質(zhì)量的影響進(jìn)行探索。首先,在討論了注塑成型中模具微結(jié)構(gòu)的填充方式之后,分析進(jìn)澆方向與模具微結(jié)構(gòu)分布方向的夾角對微流控芯片微溝槽的成型質(zhì)量造成的影響。在此基礎(chǔ)上,對微流控芯片的微溝槽分布樣式進(jìn)行了設(shè)計,以研究超聲振動對不同尺寸、不同分布情況模具微結(jié)構(gòu)的充模效果的影響。其次,在總結(jié)和歸納前人工作的基礎(chǔ)上,分析了不同作用方向和作用形式的超聲振動對注塑成型微結(jié)構(gòu)制品成型質(zhì)量的影響機理,提出了將整體作用式的超聲振動引入到注塑成型模具的型腔中,設(shè)計了包含不同振動方向的的超聲振動輔助微注塑成型模具,以期進(jìn)行型腔振動方向?qū)ξ⒘骺匦酒芗尚唾|(zhì)量影響的研究。最后,通過超聲振動輔助微注塑成型實驗,研究了超聲振動參數(shù)對PMMA材料微流控芯片成型質(zhì)量的影響。結(jié)果表明,在成型過程的不同階段對塑件施加超聲振動后,微流控芯片塑件的成型質(zhì)量會產(chǎn)生不同程度的變化。當(dāng)成型過程處于填充階段時,施加超聲振動后,隨著超聲功率的增加和振動時間在一定范圍內(nèi)的延長,微流控芯片微溝槽的上槽寬度會出現(xiàn)不斷縮小的跡象。但是當(dāng)振動時間延長到保壓階段結(jié)束以后時,微溝槽的上槽寬度將會開始出現(xiàn)增大的反彈現(xiàn)象,并容易引起微流控芯片塑件表面的振紋,振紋會隨著超聲功率的增加而逐漸地向塑件中央?yún)R聚。當(dāng)施加的超聲振動開始于保壓完成后的階段時,塑件表面上也會出現(xiàn)具有同樣變化規(guī)律的振紋。這一系列的現(xiàn)象說明,在注塑成型PMMA材料微流控芯片的過程中引入超聲作用時,超聲振動施加的階段和振動時間的選取,對塑件的成型質(zhì)量起著至關(guān)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.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN492

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本文編號：2147100