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  本文選題：薄壁注射成型　切入點(diǎn)：剪切速率　出處：《南昌大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：與常規(guī)塑件注射成型不同,在薄壁塑件注射成型中,由于薄壁塑件制品的較薄壁厚,聚合物熔體在充模過程中會很快冷卻,促使聚合物熔體更容易凝固凍結(jié),導(dǎo)致成型生產(chǎn)難度加大,容易產(chǎn)生各種成型質(zhì)量缺陷,嚴(yán)重影響了塑件產(chǎn)品的品質(zhì)質(zhì)量。聚合物注射成型過程是一種包含高度非線性、時變性的多工藝參數(shù)影響的復(fù)雜成型過程,其每個工藝參數(shù)對成型塑件產(chǎn)品質(zhì)量的好壞都具有程度各異的影響。因此分析研究注射成型生產(chǎn)過程中工藝參數(shù)條件對塑件產(chǎn)品的品質(zhì)質(zhì)量的影響并對工藝參數(shù)條件組合進(jìn)行優(yōu)化,是提高成型薄壁塑件產(chǎn)品質(zhì)量的一條行之有效的措施。本文采用聚合物注射成型模流仿真分析軟件Autodesk Moldflow Insight的流動分析模塊(Filling Packing,也可稱為Flow)對聚合物注射成型過程中聚合物熔體的充模流動行為進(jìn)行CAE有限元數(shù)值仿真模擬計算,研究了熔體溫度、模具溫度、注射時間和保壓壓力四個成型工藝參數(shù)對醫(yī)用注射器針筒成型時最大剪切速率分布場的影響,分析結(jié)果表明,在聚合物熔體充模流動方向上,靠近澆口位置附近處的剪切速率遠(yuǎn)大于其他位置的剪切速率,在距澆口0~10mm這段距離內(nèi),隨著距離的增加,最大剪切速率迅速減小。而從距離澆口10mm處至塑件產(chǎn)品的末端處,最大剪切速率的改變不甚明顯。在聚合物熔體充模厚度方向上,熔體芯層處的剪切速率最小,向表層方向逐漸增大,呈現(xiàn)比較畸形的“M”狀,在距離表面層大約0.1mm處到達(dá)剪切速率的最大值,接著再往表層減小直至表面層。最后基于最大剪切速率分布場結(jié)果對結(jié)晶度做出了預(yù)測。選取了熔體溫度、模具溫度、注射時間和保壓壓力為實驗的輸入設(shè)計變量,以垂直于裝配方向的最大體積收縮變形和最大型芯偏移為響應(yīng)輸出優(yōu)化指標(biāo),通過響應(yīng)曲面中心復(fù)合試驗設(shè)計方法耦合CAE有限元數(shù)值仿真模擬試驗,利用實驗數(shù)據(jù)分析軟件Design-Expert8.0對響應(yīng)實驗結(jié)果進(jìn)行非線性回歸擬合輸入設(shè)計變量與響應(yīng)變量之間的二次響應(yīng)曲面數(shù)學(xué)模型,研究分析了成型工藝參數(shù)條件對醫(yī)用注射器針筒成型質(zhì)量的影響顯著性及影響規(guī)律,對響應(yīng)輸出目標(biāo)進(jìn)行了多目標(biāo)優(yōu)化求解,獲取最優(yōu)成型工藝參數(shù)組合,在對其進(jìn)行仿真模擬驗證了準(zhǔn)確度后,將其應(yīng)用于實際生產(chǎn),成型出符合廠家質(zhì)量需求的醫(yī)用注射器針筒。
[Abstract]:Different from the conventional injection molding of plastic parts, in the injection molding of thin-walled plastic parts, because of the thicker thin-walled products, the polymer melts will be cooled quickly during the filling process, which makes the polymer melt solidify and freeze more easily. The process of polymer injection molding is a kind of highly nonlinear process, which leads to more difficulty in molding production and easy to produce all kinds of quality defects, which seriously affect the quality of plastic parts. The time-varying effects of multiple process parameters on the complex molding process, Each process parameter has different influence on the quality of plastic parts. Therefore, the influence of process parameters on the quality and quality of plastic parts in injection molding process is analyzed and studied. The condition combination is optimized, It is an effective measure to improve the product quality of forming thin-walled plastic parts. In this paper, the flow analysis module of polymer injection molding simulation software Autodesk Moldflow Insight is used in polymer injection molding process. The mold filling behavior of polymer melt was simulated by CAE finite element method. The effects of melt temperature, mold temperature, injection time and pressure holding pressure on the maximum shear rate distribution of the syringe were studied. The results showed that the polymer melt was filled in the direction of mold filling. The shear rate near the gate position is much higher than that near the other position, and the maximum shear rate decreases rapidly with the increase of the distance from the gate to the end of the plastic product, and from the gate to the end of the plastic product, the maximum shear rate decreases rapidly with the increase of the distance from the gate to the end of the plastic product. The change of the maximum shear rate is not obvious. In the direction of the filling thickness of polymer melt, the shear rate at the core layer of the polymer is the smallest, and gradually increases towards the surface layer, showing a more deformed "M" shape. The maximum shear rate is reached at a distance of about 0.1 mm from the surface layer, and then decreases to the surface layer. Finally, the crystallinity is predicted based on the results of the maximum shear rate distribution. The injection time and pressure holding pressure are the input design variables of the experiment. The maximum volume shrinkage deformation and the largest core offset perpendicular to the assembly direction are taken as the response output optimization index. The CAE finite element numerical simulation experiment is coupled by the complex test design method of the center of the response surface. A mathematical model of Quadric response surface between the input variables and the response variables is fitted by using the experimental data analysis software Design-Expert8.0. The influence of molding process parameters on the forming quality of syringe syringes is studied and analyzed. The multi-objective optimization solution of the response output target is carried out to obtain the optimal forming process parameters. After the accuracy is verified by simulation and simulation, the syringe syringe which meets the quality requirement of the manufacturer is formed by applying it to the actual production.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TH788;TQ320.662

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本文編號：1581245